text:
List of codecs

The following is a list of compression formats and related codecs.

Non-compression

 * Linear pulse-code modulation (LPCM, generally only described as PCM) is the format for uncompressed audio in media files and it is also the standard for CD-DA; note that in computers, LPCM is usually stored in container formats such as WAV, AIFF, or AU, or as raw audio format, although not technically necessary.
 * FFmpeg
 * Pulse-density modulation (PDM)
 * Direct Stream Digital (DSD) is standard for Super Audio CD
 * foobar2000 Super Audio CD Decoder (based on MPEG-4 DST reference decoder)
 * FFmpeg (based on dsd2pcm)
 * Pulse-amplitude modulation (PAM)

Lossless compression

 * Actively used
 * Most popular
 * Free Lossless Audio Codec (FLAC)
 * libFLAC
 * FFmpeg
 * Apple Lossless Audio Codec (ALAC)
 * Apple QuickTime
 * libalac
 * FFmpeg
 * Apple Music
 * Monkey's Audio (APE)
 * Monkey's Audio SDK
 * FFmpeg (decoder only)
 * OptimFROG (OFR)
 * Tom's verlustfreier Audiokompressor (TAK)
 * TAK SDK
 * FFmpeg (decoder only)
 * WavPack (WV)
 * libwavpack
 * FFmpeg
 * True Audio (TTA)
 * libtta
 * FFmpeg
 * Windows Media Audio Lossless (WMAL)
 * Windows Media Encoder
 * FFmpeg (decoder only)
 * Other
 * DTS-HD Master Audio, also known as DTS++ and DCA XLL
 * libdca (decoder only)
 * FFmpeg (decoder only)
 * Dolby TrueHD – Standard for DVD-Audio in Blu-ray (mathematically based on MLP)
 * FFmpeg
 * Meridian Lossless Packing (MLP), also known as Packed PCM (PPCM) – Standard for DVD-Audio in DVD
 * FFmpeg
 * MPEG-4 Audio Lossless Coding (MPEG-4 ALS)
 * SSC, DST, ALS and SLS reference software (ISO/IEC 14496-5:2001/Amd.10:2007)
 * FFmpeg (decoding only)
 * MPEG-4 Scalable Lossless Coding (MPEG-4 SLS) – Parts of it are used in HD-AAC.
 * SSC, DST, ALS and SLS reference software (ISO/IEC 14496-5:2001/Amd.10:2007)
 * RealAudio Lossless
 * RealPlayer
 * FFmpeg (decoding only)
 * BFDLAC (BFD Lossless Audio Compression). Ongoing development.
 * FXpansion's BFD3 drum software. (2013-2017)
 * L2HC - Huawei
 * Huawei Music
 * NearLink
 * Huawei FreeBuds
 * Oddball
 * ATRAC Advanced Lossless (AAL) – Extremely unpopular
 * FFmpeg (lossy decoder only)
 * Direct Stream Transfer (DST) - Only used for Direct Stream Digital
 * SSC, DST, ALS and SLS reference software (ISO/IEC 14496-5:2001/Amd.10:2007)
 * FFmpeg (decoder only)
 * Original Sound Quality (OSQ) - Only used in WaveLab
 * FFmpeg (decoding only)
 * Discontinued
 * Lossless Audio (LA) – No update for 10+ years
 * Shorten (SHN) – Officially discontinued.
 * libshn
 * FFmpeg (decoding only)
 * Lossless Predictive Audio Compression (LPAC) – Predecessor of MPEG-4 ALS
 * Lossless Transform Audio Compression (LTAC) – Predecessor of LPAC
 * MPEG-1 Audio Layer III HD (mp3HD) – Officially discontinued
 * RK Audio (RKAU) – Officially discontinued
 * FFmpeg (decoding only)

Lossy compression

 * Discrete cosine transform (DCT)
 * Modified discrete cosine transform (MDCT, used in most of the audio codecs listed below)

General/Speech hybrid

 * Unified Speech and Audio Coding (USAC, MPEG-D Part 3, ISO/IEC 23003-3)
 * exhale (encoder only; open source)
 * IETF standards:
 * Opus (RFC 6716) – based on SILK vocoder and CELT codec
 * libopus
 * FFmpeg (decoding and experimental encoding)
 * IETF Internet Draft
 * IPMR Speech Codec - used in Spirit DSP's TeamSpirit Voice&Video Engine

Neural audio codecs

 * Lyra (codec) - used in Google Duo
 * Lyra V2 - based on SoundStream neural codec
 * Satin (used by Microsoft Teams)
 * Facebook EnCodec

General

 * Adaptive differential pulse-code modulation (ADPCM, also called adaptive delta pulse-code modulation)
 * Adaptive Transform Acoustic Coding (ATRAC, used in MiniDisc devices)
 * FFmpeg (decoder only)
 * ATSC/ETSI standards:
 * Dolby Digital (AC3, ATSC A/52, ETSI TS 102 366)
 * FFmpeg
 * liba52 (decoder only)
 * Dolby Digital Plus (E-AC-3, ATSC A/52:2012 Annex E, ETSI TS 102 366 Annex E)
 * FFmpeg
 * DTS Coherent Acoustics (DTS, Digital Theatre System Coherent Acoustics, ETSI TS 102 114)
 * FFmpeg
 * libdca (decoder only)
 * Dolby AC-4 (ETSI TS 103 190)
 * Impala Blackbird audio codec
 * ITU standards:
 * G.719
 * G.722
 * FFmpeg
 * G.722.1 (subset of Siren7) and G.722.1 Annex C (subset of Siren14)
 * libg722_1
 * libsiren (part of libmsn and msn-pecan)
 * G.722.2
 * 3GPP TS 26.173 – AMR-WB speech Codec (C-source code) –  reference implementation
 * opencore-amr (decoder)
 * VisualOn AMR-WB encoder
 * FFmpeg (decoding only)
 * EVS
 * MPEG-1 Audio and MPEG-2 Audio
 * layer I (MP1) (MPEG-1, MPEG-2 and non-ISO MPEG-2.5)
 * FFmpeg (decoder only)
 * layer II (MP2) (MPEG-1, MPEG-2 and non-ISO MPEG-2.5)
 * FFmpeg
 * tooLame (encoding only)
 * twoLame (encoding only)
 * layer III (MP3) (MPEG-1, MPEG-2 and non-ISO MPEG-2.5)
 * FFmpeg (decoding only)
 * LAME (encoding only)
 * Advanced Audio Coding (AAC) (MPEG-2 Part 7)
 * FAAC (encoder) and FAAD (decoder)
 * FFmpeg
 * iTunes
 * Nero AAC Codec
 * VisualOn AAC Encoder (a.k.a. libvo_aacenc)
 * Fraunhofer FDK AAC
 * libaacplus
 * MPEG-4 Audio
 * Advanced Audio Coding (AAC, MPEG-4 Part 3 subpart 4), HE-AAC and AAC-LD
 * FAAC, FAAD2
 * FFmpeg
 * iTunes
 * Nero AAC Codec
 * MPEG-4 AAC reference software (ISO/IEC 14496-5:2001)
 * Harmonic and Individual Lines and Noise (HILN, MPEG-4 Parametric Audio Coding)
 * MPEG-4 reference software (ISO/IEC 14496-5:2001)
 * TwinVQ
 * MPEG-4 reference software (ISO/IEC 14496-5:2001)
 * FFmpeg (decoding only)
 * BSAC (Bit-Sliced Arithmetic Coding)
 * MPEG-4 reference software (ISO/IEC 14496-5:2001)
 * MPEG-H
 * MPEG-H 3D Audio
 * Musepack (a.k.a. MPEGplus)
 * Musepack SV8 Tools
 * FFmpeg (decoding only)
 * NICAM
 * AT&T Perceptual Audio Coder
 * Precision Adaptive Subband Coding (PASC; a variant of MP1; used in Digital Compact Cassette)
 * QDesign (purchased by DTS)
 * QDesign Music Codec – used in Apple QuickTime
 * FFmpeg (decoding only)
 * PictureTel (purchased by Polycom)
 * Siren 7
 * libg722_1
 * libsiren (part of libmsn and msn-pecan)
 * FFmpeg (decoder only)
 * Siren 14
 * libg722_1
 * vgmstream (decoder only)
 * Siren 22
 * NTT TwinVQ
 * FFmpeg (decoder only)
 * NTT TwinVQ Encoder, NTT TwinVQ Player
 * Voxware MetaSound (a variant of NTT TwinVQ)
 * Windows Media Player (voxmsdec.ax)
 * FFmpeg (decoder only)
 * Vorbis
 * aoTuV
 * FFmpeg
 * libvorbis
 * Tremor (decoder only)
 * Windows Media Audio (WMA)
 * Windows Media Encoder
 * FFmpeg

AES3

 * SMPTE 302M
 * FFmpeg (decoder only)
 * Dolby E
 * FFmpeg (decoder only)

Bluetooth

 * Bluetooth Special Interest Group
 * Low Complexity Subband Coding (SBC)
 * BlueZ's SBC library (libsbc)
 * Fluoride Bluetooth stack (successor of BlueDroid)
 * FFmpeg
 * CVSD 8 kHz - used in Hands-Free Profile (HFP)
 * modified SBC (mSBC) - used in Hands-Free Profile (HFP)
 * BlueZ's SBC library (libsbc)
 * Fluoride Bluetooth stack
 * FFmpeg
 * SBC XQ
 * PulseAudio's bluetooth stack (encoder only)
 * PipeWire's bluetooth stack (encoder only)
 * LC3 (Low Complexity Communication Codec)
 * Google's liblc3 (open source) - used in Android 13 and later
 * ETSI
 * LC3plus (ETSI TS 103 634)
 * Google's liblc3 (open source)
 * Qualcomm Technologies International (formerly CSR)
 * aptX (a.k.a. apt-X)
 * Qualcomm libaptX
 * FFmpeg
 * aptX HD
 * Qualcomm libaptXHD
 * FFmpeg
 * aptX Low Latency
 * aptX Adaptive
 * FastStream - a variant of SBC codec for bi-directional audio transmission
 * Sony
 * LDAC
 * libldac (encoder only) - used in Android Oreo
 * libldacdec (decoder only)
 * HWA Alliance/Savitech
 * LHDC
 * HWA encoder/decoder
 * LLAC
 * HWA encoder/decoder
 * HiBy
 * Ultra Audio Transmission (UAT)
 * Samsung
 * Samsung HD/UHQ-BT codec
 * Samsung Scalable codec
 * Samsung Seamless codec
 * MQA
 * MQair

Digital radio

 * Hybrid Digital Coding - used in HD Radio (a.k.a. NRSC-5)
 * NRSC-5 receiver for rtl-sdr (decoder only)

Voice
(low bit rate, optimized for speech)
 * Linear predictive coding (LPC, used in most of the speech codecs listed below)
 * Code-excited linear prediction (CELP)
 * Algebraic code-excited linear prediction (ACELP)
 * Xiph.Org Foundation
 * Speex, patent free
 * libspeex
 * FFmpeg (decoder only)
 * Dialogic ADPCM (VOX)
 * FFmpeg (decoder only)
 * ITU standards:
 * G.711 (a-law and μ-law companding; 64 kbit/s), also known as PCM of voice frequencies
 * Sun Microsystems's public domain implementation
 * FFmpeg (libavcodec)
 * G.711.0 (G.711 LLC)
 * G.711.1 (Wideband extension for G.711; 64/80/96 kbit/s)
 * G.711.1D (Super-wideband extension for G.711.1; 96/112/128 kbit/s)
 * G.718 (8/12/16/24/32 kbit/s)
 * G.718B (Super-wideband extension for G.718; 28–48 kbit/s)
 * G.719
 * G.721 (superseded by G.726; 32 kbit/s)
 * Sun Microsystems's public domain implementation
 * G.722 (SB-ADPCM; 48/56/64 kbit/s)
 * FFmpeg
 * G.722B (Super-wideband extension for G.722; 64/80/96 kbit/s)
 * G.722.2 (AMR-WB)
 * 3GPP TS 26.173 – AMR-WB speech Codec (C-source code) –  reference implementation
 * opencore-amr (decoder)
 * FFmpeg (decoder only)
 * G.723 (24 and 40 kbit/s DPCM, extension to G.721, superseded by G.726)
 * Sun Microsystems's public domain implementation
 * G.723.1 (MPC-MLQ or ACELP; 5.3/6.3 kbit/s)
 * FFmpeg
 * G.726 (ADPCM; 16/24/32/40 kbit/s)
 * Sun Microsystems's public domain implementation
 * FFmpeg (libavcodec)
 * G.727
 * Sun Microsystems's public domain implementation
 * G.728 (LD-CELP; 16 kbit/s)
 * G.729 (CS-ACELP; 8 kbit/s)
 * FFmpeg (decoder only)
 * G.729a
 * G.729b
 * G.729ab
 * G.729d (6.4 kbit/s)
 * FFmpeg (decoder only)
 * G.729e (11.8 kbit/s)
 * G.729.1 (G.729 Annex J; Wideband extension for G.711; 8–32 kbit/s)
 * G.729.1E (Super-wideband extension for G.729.1)
 * Google
 * internet Speech Audio Codec (iSAC)
 * WebRTC
 * Nellymoser Asao Codec
 * FFmpeg (libavcodec)
 * PictureTel PT716, PT716plus
 * PictureTel PT724
 * RTAudio – used by Microsoft Live Communication Server
 * SVOPC – used by Skype
 * OpenLPC – created by Future Dynamics
 * HawkVoice (libHVDI)
 * ANSI/SCTE
 * ANSI/SCTE 24-21 2006 (BroadVoice16)
 * BroadVoice Speech Codec Open Source C Code
 * ANSI/SCTE 24-22 2013 (iLBCv2.0)
 * ANSI/SCTE 24-23 2007 (BroadVoice32)
 * BroadVoice Speech Codec Open Source C Code
 * IETF RFCs:
 * Internet Low Bit Rate Codec (iLBC, RFC 3951) – developed by Global IP Solutions/Google
 * WebRTC
 * IETF Internet Draft
 * SILK (used by Skype)
 * CELT (developed by Xiph.Org Foundation)
 * libcelt
 * MPEG-4 Audio
 * MPEG-4 CELP
 * MPEG-4 HVXC
 * Skyphone MPLP
 * Inmarsat
 * INMARSAT-M IMBE
 * Inmarsat Mini-M AMBE

Microsoft DirectPlay
Those codecs are used by many PC games which use voice chats via Microsoft DirectPlay API.
 * Voxware MetaVoice
 * Windows Media Player (voxmvdec.ax)
 * Truespeech
 * Windows Media Player (tssoft32.acm)
 * FFmpeg (decoder only)
 * MS GSM
 * Windows Media Player (msgsm32.acm)
 * libgsm
 * FFmpeg (decoder only)
 * MS-ADPCM
 * Windows Media Player (msadp32.acm)
 * FFmpeg

Digital Voice Recorder

 * International Voice Association (IVA) standards:
 * Digital Speech Standard / Standard Play (DSS-SP)
 * FFmpeg (decoding only)
 * Digital Speech Standard / Quality Play (DSS-QP)
 * Sony LPEC
 * Truespeech Triple Rate CODER (TRC) –  used in some pocket recorders
 * Intermetall MI-SC4 - used by voice recorders such as RadioShack Digital Recorder and HyperHyde
 * FFmpeg (decoder only)

Generation 2

 * European Telecommunications Standards Institute (ETSI) GSM
 * Full Rate (GSM 06.10, RPE-LTP)
 * libgsm
 * FFmpeg (decoder only)
 * Half Rate (GSM 06.20, VSELP 5.6 kbit/s)
 * Enhanced Full Rate (GSM 06.60, ACELP 12.20 kbit/s, compatible with AMR mode AMR_12.20)
 * Telecommunications Industry Association (TIA) IS-95 (a.k.a. cdmaOne)
 * IS-96A (QCELP 8 kbit/s)
 * IS-127 (EVRC 8 kbit/s)
 * IS-733 (QCELP 13 kbit/s)
 * Telecommunications Industry Association (TIA) IS-54/IS-136 (a.k.a. Digital AMPS)
 * IS-85 (VSELP 8kbit/s)
 * ITU-T G.191's IS-54 implementation
 * IS-641 (ACELP 7.4 kbit/s, compatible with AMR mode AMR_7.40)
 * Association of Radio Industries and Businesses (ARIB) RCR STD-27 (PDC)
 * PDC-HR (PSI-CELP 3.45 kbit/s)
 * PDC-FR (VSELP 11.2 kbit/s)
 * PDC-EFR CS-ACELP 8 kbit/s (a.k.a. G.729)
 * PDC-EFR ACELP 6.7 kbit/s (compatible with AMR mode AMR_6.70)

Generation 3/4

 * 3rd Generation Partnership Project (3GPP)
 * Adaptive Multi-Rate (AMR)
 * AMR-NB
 * 3GPP TS 26.073 – AMR speech Codec (C-source code) –  reference implementation
 * opencore-amr (one may compile ffmpeg with—enable-libopencore-amrnb to incorporate the OpenCORE lib)
 * FFmpeg (by default decoder only, but see above the compiling options to incorporate the OpenCORE lib)
 * AMR-WB
 * 3GPP TS 26.173 – AMR-WB speech Codec (C-source code) –  reference implementation
 * opencore-amr (decoder), from OpenCORE (one may compile ffmpeg with—enable-libopencore-amrwb to incorporate the OpenCORE lib)
 * vo-amrwbenc (encoder), from VisualOn, included in Android (one may compile ffmpeg with—enable-libvo-amrwbenc to incorporate the VisualOn lib)
 * FFmpeg (by default decoder only, but see above the compiling options).
 * AMR-WB+
 * 3GPP TS 26.273 – AMR-WB+ speech Codec (C-source code) –  reference implementation
 * Enhanced Voice Services (EVS)
 * 3GPP TS.26.443 – Codec for Enhanced Voice Services (EVS) – ANSI C code (floating-point)
 * 3rd Generation Partnership Project 2 (3GPP2)
 * Enhanced Variable Rate Codec (EVRC, a.k.a. IS-127) – based on RCELP
 * FFmpeg (decoder only)
 * Enhanced Variable Rate Codec B (EVRC-B)
 * QCELP (Qualcomm Code Excited Linear Prediction)
 * QCELP-8 (a.k.a. SmartRate or IS-96C)
 * FFmpeg (decoder only)
 * QCELP-13 (a.k.a. PureVoice or IS-733)
 * FFmpeg (decoder only)
 * Selectable Mode Vocoder (SMV)
 * Variable Multi Rate – WideBand (VMR-WB)

Professional mobile radio

 * APCO
 * Project 25 Phase 2 Enhanced Full-Rate (AMBE+2 4400bit/s with 2800bit/s FEC)
 * Project 25 Phase 2 Half-Rate (AMBE+2 2450bit/s with 1150bit/s FEC) – also used in NXDN and DMR
 * mbelib (decoder only)
 * Project 25 Phase 1 Full Rate (IMBE 7200bit/s)
 * mbelib (decoder only)
 * European Telecommunications Standards Institute (ETSI)
 * ETS 300 395-2 (TETRA ACELP 4.6kbit/s)

 * TETRAPOL
 * RPCELP 6 kbit/s
 * D-STAR Digital Voice (AMBE 2400bit/s with 1200bit/s FEC)
 * mbelib (decoder only)
 * Professional Digital Trunking System Industry Association (PDT Alliance) standards:
 * NVOC – used in China
 * Spirit DSP RALCWI
 * DSPINI
 * SPR Robust
 * TWELP Robust
 * Codec2
 * libcodec2
 * RL-CELP (used in Japanese railways )

Military

 * U.S. Department of Defense (DoD) Federal Standard:
 * FS-1015 (a.k.a. LPC-10)
 * HawkVoice (libHVDI)
 * FS-1016 (CELP)
 * HawkVoice (libHVDI)
 * FS-1023 (CVSD 12kbit/s)
 * United States Military Standard (MIL-STD)
 * MIL-STD-188 113 (CVSD 16 kbit/s and 32 kbit/s)
 * SoX (libsox)
 * MIL-STD-3005 (a.k.a. MELP)
 * Texas Instruments' 2.4 kbit/s MELP Proposed Federal Standard speech coder
 * NATO
 * STANAG 4198 (a.k.a. LPC-10e)
 * SpanDSP (open source)
 * STANAG-4591 (a.k.a. MELPe)
 * Microsoft Speech coder
 * BBN NRV – developed in DARPA program

Video games

 * Bink Audio, Smacker Audio
 * FFmpeg (decoder only)
 * Actimagine (Nintendo European Research & Development) FastAudio
 * MobiclipDecoder (decoder only)
 * FFmpeg (decoder only)
 * Nintendo GCADPCM (a.k.a. DSP ADPCM or THP ADPCM) - used in GameCube, Wii and Nintendo 3DS.
 * vgmstream (decoder only)
 * VGAudio
 * FFmpeg (decoder only)
 * Sony VAG (a.k.a. Sony PSX ADPCM)
 * vgmstream (decoder only)
 * FFmpeg (decoder only)
 * Sony HEVAG - used in PS Vita.
 * vgmstream (decoder only)
 * Sony ATRAC9 - used in PS4 and PS Vita.
 * VGAudio (decoder only)
 * FFmpeg (decoder only)
 * Microsoft XMA - WMA variants for Xbox 360 hardware decoding.
 * FFmpeg (decoder only)
 * Xbox ADPCM
 * vgmstream (decoder only)
 * CRI ADX ADPCM
 * vgmstream (decoder only)
 * VGAudio
 * FFmpeg
 * CRI HCA/HCA-MX - used in CRI ADX2 middleware.
 * vgmstream (decoder only)
 * VGAudio
 * FFmpeg (decoder only)
 * libcgss
 * HCADecoder (decoder only)
 * FMOD FADPCM
 * vgmstream (decoder only)

Text compression formats

 * BiM
 * Continuous Media Markup Language (CMML)
 * MPEG-4 Part 17 (e.g. 3GPP Timed Text)
 * ttyrec

Non-compression

 * RGB 4:4:4 (only linear, transfer-converted and bit-reduced also sort of compression up to about 3:1 for HDR)
 * YUV 4:4:4/4:2:2/4:1:1/4:2:0 (all lower 4:4:4 is spatially compressed up to 2:1 for 4:2:0 with specific colour distortions).
 * Intel IYUV
 * 10-bit uncompressed video
 * Composite digital signal - used by SMPTE D-2 and D-3 broadcast digital videocassettes
 * Avid DNxUncompressed
 * V210

Analog signals

 * PAL broadcast signal
 * Pyctools-PAL (open source)

 * NTSC broadcast signal
 * gr-ntsc (open source)

 * LaserDisc RF signal
 * ld-decode (open source)
 * VHS / S-VHS / U-Matic RF signal
 * VHS-Decode (open source)
 * Composite Video Baseband Signal (CVBS)
 * VHS-Decode's CVBS-Decode (open source)

Lossless video compression

 * ITU-T/ISO/IEC standards:
 * H.264 lossless
 * x264 (encoder only)
 * FFmpeg (decoder only, uses x264 for encoding)
 * H.265 lossless
 * x265 (encoder only)
 * UHDcode (decoder only, uses x265 to read HEVC encoded files)
 * FFmpeg (decoder only, uses x265 for encoding)
 * Motion JPEG 2000 lossless
 * libopenjpeg
 * JPEG XS lossless
 * FastTICO-XS
 * IETF standards:
 * FFV1 (RFC 9043) –  FFV1's compression factor is comparable to Motion JPEG 2000, but based on quicker algorithms (allows real-time capture). Written by Michael Niedermayer and published as part of FFmpeg under GNU LGPL.
 * FFmpeg
 * SMPTE standards:
 * VC-2 HQ lossless (a.k.a. Dirac Pro lossless)
 * libdirac
 * libschroedinger

 * Alparysoft Lossless Video Codec (Alpary)
 * Apple Animation (QuickTime RLE)
 * QuickTime
 * FFmpeg
 * ArithYuv
 * AV1
 * libaom
 * AVIzlib
 * LCL (VfW codec) MSZH and ZLIB
 * FFmpeg
 * Autodesk Animator Codec (AASC)
 * FFmpeg (decoder only)
 * CAI Format
 * CamStudio GZIP/LZO
 * FFmpeg (decoder only)
 * Chennai Codec (EVX-1)
 * Cairo Experimental Video Codec (open source)
 * Dxtory
 * FFmpeg (decoder only)
 * FastCodec
 * Flash Screen Video v1/v2
 * FFmpeg
 * FM Screen Capture Codec
 * FFmpeg (decoder only)
 * Fraps codec (FPS1)
 * FFmpeg (decoder only)
 * Grass Valley Lossless
 * Grass Valley Codec Option
 * FFmpeg (decoder only)
 * Huffyuv Huffyuv (or HuffYUV) was written by Ben Rudiak-Gould and published under the terms of the GNU GPL as free software, meant to replace uncompressed YCbCr as a video capture format. It uses very little CPU but takes a lot of disk space. See also ffvhuff which is an "FFmpeg only" version of it.
 * FFmpeg
 * IgCodec
 * Intel RLE
 * innoHeim/Rsupport Screen Capture Codec
 * FFmpeg (decoder only)
 * Lagarith A more up-to-date fork of Huffyuv is available as Lagarith
 * Lagarith Codec (VfW codec)
 * FFmpeg (decoder only)
 * LOCO - based on JPEG-LS
 * FFmpeg (decoder only)
 * MagicYUV
 * MagicYUV SDK
 * FFmpeg
 * Microsoft RLE (MSRLE)
 * FFmpeg
 * MSU Lossless Video Codec
 * MSU Screen Capture Lossless
 * - based on PNG
 * FFmpeg
 * ScreenPresso (SPV1)
 * FFmpeg (decoder only)
 * ScreenPressor - a successor of MSU Screen Capture Lossless
 * FFmpeg (decoder only)
 * SheerVideo
 * FFmpeg (decoder only)
 * Snow lossless
 * FFmpeg
 * TechSmith Screen Capture Codec (TSCC)
 * EnSharpen Video Codec for QuickTime
 * FFmpeg (decoder only)
 * Toponoky
 * Ut Video Codec Suite
 * libutvideo
 * FFmpeg
 * VBLE
 * FFmpeg (decoder only)
 * VMnc VMware screen codec - used by VMware Workstation
 * FFmpeg (decoder only)
 * VP9 by Google
 * libvpx
 * FFmpeg (decoder only)
 * YULS
 * ZeroCodec
 * FFmpeg (decoder only)
 * ZMBV (Zip Motion Block Video) Codec - used by DOSBox
 * FFmpeg

Lossless game codecs

 * DXA
 * ScummVM Tools (encoder only)
 * FFmpeg (decoder only)

Lossy compression

 * Discrete cosine transform (DCT, used in Digital Betacam and most of the video codecs listed below)

General

 * ITU-T/ISO/IEC standards:
 * H.120
 * H.261 (a.k.a. Px64)
 * FFmpeg H.261 (libavcodec)
 * Microsoft H.263
 * MPEG-1 Part 2 (MPEG-1 Video)
 * FFmpeg
 * MainConcept MPEG-1
 * TMPGEnc
 * H.262/MPEG-2 Part 2 (MPEG-2 Video)
 * Canopus ProCoder
 * Cinema Craft Encoder
 * FFmpeg
 * InterVideo Video Decoder
 * MainConcept MPEG-2
 * Microsoft H.263
 * TMPGEnc
 * H.263
 * FFmpeg H.263 (libavcodec)
 * MPEG-4 Part 2 (MPEG-4 Advanced Simple Profile)
 * 3ivx
 * DivX
 * libavcodec
 * HDX4
 * Nero Digital
 * Xvid
 * H.264/MPEG-4 AVC or MPEG-4 Part 10 (MPEG-4 Advanced Video Coding), approved for Blu-ray
 * CoreAVC (decoder only; limited to below Hi10P profile)
 * MainConcept
 * Nero Digital
 * QuickTime H.264
 * Sorenson AVC Pro codec, Sorenson's new implementation
 * OpenH264 (baseline profile only)
 * x264 (encoder only; supports some of Hi422P and Hi444PP features)
 * FFmpeg (decoder only)
 * MPEG-4 AVC variants:
 * MPEG-4 Web Video Coding or MPEG-4 Part 29 – a subset of MPEG-4 AVC baseline profile
 * XAVC
 * HEVC (High Efficiency Video Coding, H.265, MPEG-H part 2)
 * x265 (encoder only)
 * Versatile Video Coding (H.266, VVC)
 * VVC Test Model (VTM reference software for VVC; open source)
 * Fraunhofer Versatile Video Decoder (open source; decoder only)
 * Fraunhofer Versatile Video Encoder (open source; encoder only)
 * FFmpeg (decoder only)
 * Video Coding for Browsers (VCB)/VP8 (MPEG-4 Part 31, ISO/IEC 14496-31, RFC 6386)
 * libvpx
 * FFmpeg
 * Internet Video Coding (ISO/IEC 14496-33, MPEG-4 IVC)
 * Essential Video Coding (EVC; MPEG-5 Part 1; under-development)
 * eXtra-fast Essential Video Encoder (open source; encoder only)
 * eXtra-fast Essential Video Decoder (open source; decoder only)
 * LCEVC, MPEG-5 Part 2 (Low Complexity Enhancement Video Coding)
 * IETF Internet Draft (NETVC)
 * xvc
 * Divideon's reference implementation (open source)
 * Thor (forms the basis of AV1)
 * Cisco's reference implementation (open source)
 * SMPTE standards:
 * VC-1 (SMPTE 421M, subset of Windows Media Video)
 * FFmpeg (decoder only)
 * Dirac (SMPTE 2042-1)
 * Schrödinger
 * dirac-research
 * FFmpeg (decoder only)
 * Alliance for Open Media
 * AV1 (AOMedia Video 1)
 * libaom
 * SVT-AV1
 * rav1e (encoder only)
 * dav1d (decoder only)
 * libgav1 (decoder only)
 * Xiph.Org Foundation
 * Daala (under development, basis (alongside other formats) of AV1)
 * libdaala (open source)
 * Theora (based on VP3)
 * FFmpeg (decoding only)
 * libtheora (open source)
 * Apple Video (Apple RPZA)
 * QuickTime
 * FFmpeg
 * Blackbird FORscene video codec
 * Firebird Original FORscene video codec
 * Digital Video Interactive standards:
 * RTV 2.1 (a.k.a. Indeo 2)
 * FFmpeg (decoder only)
 * PLV (Production Level Video)
 * ActionMedia II driver (decoder only)
 * Indeo 3 /4/5
 * FFmpeg (decoder only)
 * Microsoft Video 1 (MSV1, MS-CRAM, based on MotiVE)
 * FFmpeg (decoder only)
 * Open Media Commons standards:
 * OMS Video (based on H.261)
 * On2 Technologies TrueMotion VP3/VP4, VP5, VP6, VP7; under the name The Duck Corporation: TrueMotion S, TrueMotion 2, TrueMotion RT 2.0
 * FFmpeg (decoder only)
 * RealVideo 1, G2, 8, 9 and 10
 * FFmpeg
 * RealMedia HD SDK
 * RealVideo Fractal Codec (a.k.a. Iterated Systems ClearVideo)
 * FFmpeg (decoder only)
 * RealMedia HD (a.k.a. RealVideo 11)
 * RealMedia HD SDK
 * Snow Wavelet Codec
 * Sorenson Video, Sorenson Spark
 * FFmpeg
 * VP9 by Google; VP10 was not released and instead was integrated into AV1
 * libvpx
 * FFmpeg
 * Windows Media Video (WMV)
 * WAX (Part of the Windows Media Series)
 * FFmpeg
 * Guobiao standards (GB/T)
 * Audio Video Standard (AVS)
 * AVS1-P2 (GB/T 20090.2-2006) - used in China Blue High-definition Disc.
 * FFmpeg (decoding only)
 * AVS1-P7 (AVS-M; under-development)
 * AVS2-P2 (GB/T 33475.2-2016, IEEE 1857.4 (draft))
 * uAVS2 Encoder
 * xavs2 (encoder only)
 * davs2 (libdavs2; decoder only)
 * AVS3-P2 (draft, IEEE1857.10)
 * uavs3e (encoder only)
 * uavs3d (decoder only)

Scalable
VP8, VP9, AV1, and H.266/VVC support scalable modes by default.

 * Scalable Video Coding (H.264/SVC; an extension of H.264/MPEG-4 AVC)
 * Scalable High Efficiency Video Coding (SHVC; an extension of H.265/HEVC)

Intra-frame-only

 * Motion JPEG
 * FFmpeg
 * Morgan Multimedia M-JPEG
 * Pegasus PICVideo M-JPEG
 * MainConcept M-JPEG
 * ISO/IEC standard
 * Motion JPEG 2000 (ISO/IEC 15444-3, ITU-T T.802)
 * libopenjpeg
 * FFmpeg
 * Morgan Multimedia M-JPEG2000
 * Morgan Multimedia dcpPlayer (decoder only)
 * JPEG XS (ISO/IEC 21122) Lightweight Low latency video codec
 * intoPIX fastTICO-XS
 * DV (IEC 61834)
 * FFmpeg
 * MPEG-4 SStP (ISO/IEC 14496-2)
 * FFmpeg
 * Motion JPEG XR (ISO/IEC 29199-3, ITU-T T.833)
 * Animated JPEG XL (ISO/IEC 18181)
 * libjxl
 * Apple ProRes 422/4444
 * FFmpeg
 * Apple Intermediate Codec
 * FFmpeg (decoder only)
 * Apple Pixlet
 * FFmpeg (decoder only)
 * AVC-Intra
 * x264 (encoder only)
 * FFmpeg (decoder only)
 * AVC-Ultra – a subset of MPEG-4 AVC Hi444PP profile
 * XAVC-I
 * CineForm HD
 * CineForm-SDK –  developed by GoPro (open source)
 * FFmpeg
 * SMPTE standard
 * VC-2 SMPTE standard (a.k.a. Dirac Pro. SMPTE ST 2042)
 * Schrödinger
 * dirac-research
 * VC-2 Reference Encoder and Decoder –  developed by BBC (open source)
 * FFmpeg (the encoder only supports VC-2 HQ profile)
 * VC-3 SMPTE standard (SMPTE ST 2019)
 * Avid DNxHD
 * FFmpeg
 * VC-5 SMPTE standard (SMPTE ST 2073; a superset of CineForm HD)
 * Grass Valley HQ/HQA/HQX
 * Grass Valley Codec Option
 * FFmpeg (decoder only)
 * NewTek NT25
 * NewTek SpeedHQ - used in Network Device Interface (NDI) protocol
 * NewTek Codec
 * FFmpeg

Stereoscopic 3D

 * Multiview Video Coding

Security and surveillance cameras

 * Guobiao standards (GB/T)
 * AVS-S-P2 (suspended )
 * SVAC (GB/T 25724-2010)
 * Infinity CCTV Codec (IMM4/IMM5/IMM6)
 * FFmpeg (IMM4 and IMM5 decoder only)

CD-ROM or CD-related video codecs

 * CDXL codec
 * FFmpeg (decoder only)
 * Cinepak (a.k.a. Apple Compact Video)
 * FFmpeg
 * Photo CD codec
 * FFmpeg (decoder only)
 * MotionPixels - used in MovieCD
 * FFmpeg (decoder only)
 * CD+G (CD+Graphics) codec
 * FFmpeg (decoder only)
 * VLC (decoder only)
 * CD+EG (CD+Extended Graphics) codec

Network video codecs

 * SMPTE RDD
 * LLVC (Low Latency Video Codec; SMPTE RDD 34) - used in Networked Media Interface (NMI; SMPTE RDD 40)
 * HEVC-SCC (Screen Content Coding Extensions)
 * ZRLE (RFC 6143 7.7.6) - used by VNC
 * Sun Microsystems's CellB video (RTP playload type 25) - used in Solaris's SunVideo Plus and Lawrence Berkeley National Laboratory's vic (Video Conferencing Tool)
 * Xerox PARC's Network Video (nv; RTP playload type 28) - used in Xerox's nv and Lawrence Berkeley National Laboratory's vic (Video Conferencing Tool)
 * CU-SeeMe video codec
 * GoToMeeting codec
 * FFmpeg (decoder only)

Bayer video codecs

 * CinemaDNG (created by Adobe; used in Blackmagic cameras)
 * Redcode RAW (used in RED cameras) – a modified version of JPEG 2000
 * libredcode
 * ArriRaw (used in Arri cameras)
 * Cineform RAW (used in Silicon Imaging cameras)
 * CineForm-SDK
 * Blackmagic RAW (used in Blackmagic cameras)
 * Blackmagic RAW SDK
 * Cintel RAW (used in Cintel Scanner )
 * FFmpeg (decoder only)
 * Apple ProRes RAW
 * intoPIX TICO RAW
 * intoPIX fastTICO-RAW SDK & TICO-RAW FPGA/ASIC libraries
 * Canon CRX - used in Canon Cinema Raw Light movie
 * Canon RAW Plugin for Avid Media Access
 * LibRaw (decoder only; open source)

Video games

 * Bink Video, Smacker video
 * FFmpeg
 * libavcodec
 * Nintendo Mobiclip video codec
 * FFmpeg (decoder only)
 * CRI Sofdec codec - a MPEG variant with 11-bit DC and color space correction; used in Sofdec middleware
 * CRI P256 - used in Sofdec middleware for Nintendo DS
 * Indeo Video Interactive (aka Indeo 4/5) - used in PC games for Microsoft Windows
 * FFmpeg (decoder only)
 * Intel Indeo Video

Real-time

 * RivaTuner video codec (RTV1/RTV2)
 * FFmpeg (RTV1 decoder only)
 * Hap/Hap Alpha/Hap Q
 * VIDVOX hap codec
 * FFmpeg
 * DXV Codec
 * Resolume DXV Codec
 * FFmpeg
 * NotchLC
 * FFmpeg (decoder only)
 * VESA Display Stream Compression (DSC)
 * VESA Display Compression-M (VDC-M)

title: List of codecs


text:
Category:Polyforms

In recreational mathematics, a polyform is a plane figure constructed by joining together identical basic polygons. The basic polygon is often (but not necessarily) a convex plane-filling polygon, such as a square or a triangle. More specific names have been given to polyforms resulting from specific basic polygons, as detailed in the table below. For example, a square basic polygon results in the well-known polyominoes.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Category:Polyforms


text:
Category:2-10-2 locomotives

Locomotives classified 2-10-2 under the Whyte notation of locomotive axle arrangements.
 * The equivalent UIC classification of locomotive axle arrangements is 1′E1′ locomotives.

title: Category:2-10-2 locomotives


text:
Wikipedia:Articles for deletion/Shmuck

Shmuck
Shmuck was proposed for deletion. This page is an archive of the discussion about the proposed deletion. This page is no longer live. Further comments should be made on the article's talk page rather than here so that this page is preserved as an historic record. The result of the debate was delete.

Pointless dicdef. Luigi30 23:54, 9 Dec 2004 (UTC)

 * Delete wrong spelling Aviationwiz 17:57, 10 Dec 2004 (UTC)

 * Delete (speedy?), possibly move to Wiktionary. --MarkSweep 00:29, 10 Dec 2004 (UTC)
 * Delete - link to existing Wiktionary entry under correct spelling, Schmuck. Guybrush 00:44, 10 Dec 2004 (UTC)
 * Delete. P Ingerson 01:44, 10 Dec 2004 (UTC)
 * Delete: Incorrect duplicate. Geogre 01:49, 10 Dec 2004 (UTC)
 * Delete. create redirect in Wiktionary. Gsd97jks 18:53, 14 Dec 2004 (UTC)

This page is now preserved as an archive of the debate and, like other '/delete' pages is no longer 'live'. Subsequent comments on the issue, the deletion or on the decision-making process should be placed on the relevant 'live' pages. Please do not edit this page.

title: Wikipedia:Articles for deletion/Shmuck


text:
Máire Ní Chathasaigh

Máire Ní Chathasaigh (born 1956) is an Irish harpist, composer and singer.

Biography
She was born in Bandon, County Cork, Ireland, in a musical family. She learned to playthe harp when she was eleven. She created new harp ornamentation techniques that made its stylistically accurate performance possible. Having won All-Ireland (Fleadh Cheoil na hÉireann) harp competitions at under-fourteen and under-eighteen levels, she then, in the mid-1970s, won the Senior All-Ireland competition three years in succession. She also won the Pan-Celtic Harp Competition at junior and senior levels.

She was the 2001 recipient of TG4 Gradam Ceoil Ceoltóir na Bliana / Musician of the Year, awarded "for the excellence and pioneering force of her music, the remarkable growth she has brought to the music of the harp and for the positive influence she has had on the young generation of harpers".

In 1985 she recorded The New-Strung Harp, the first harp album to concentrate primarily on traditional Irish dance music. Her stylistic innovations made her famous in the Celtic music scene.

Her partnership with English guitarist Chris Newman made its début on the main stage at the 1987 Cambridge Folk Festival. Since then they have toured as a duo all over Europe, North America, Australasia and Japan.

In 1988 they recorded The Living Wood, their first duo album, and since then they have recorded six further duo albums and a quartet album, Heartstring Sessions, with Ní Chathasaigh's sister Nollaig Casey and Nollaig's husband Arty McGlynn (all four toured together in Europe, North America and Australasia as the Heartstring Quartet). In 2015 Ní Chathasaigh recorded a trio album, Sibling Revelry, with her sisters Nollaig Casey and Mairéad Ní Chathasaigh. All albums were critically-acclaimed.

She features on the cover of the book Bringing It All Back Home and the June–July 2017 issue of Germany's Folk Magazin and of Comhaltas Ceoltóirí Éireann's magazine, Treoir. She and Chris Newman were featured on the cover, and in an article within, the April / May 2021 issue of The Living Tradition magazine.

She is profiled in Celtic Women in Music by Mairéad Sullivan, The Rough Guide to Irish Music and a number of magazine and newspaper articles.

A TV documentary programme about Ní Chathasaigh and her sister Nollaig (also featuring their sister Mairéad, together with Chris Newman and Nollaig's late husband Arty McGlynn) was originally broadcast on TG4 on November 29, 2020, and re-broadcast 13 February 2022, as part of its  'Sé mo Laoch series. It can currently be watched on the TG4 Player here.

Máire has been giving masterclasses and disseminating her ideas and techniques in Ireland, the UK, Europe, North America and Australasia since the mid-1970s. Her arrangements have been published in two books, ''The Irish Harper Vols. I and II'', and she has an honours degree in Celtic Studies from University College Cork.

Albums

 * The New Strung Harp (Temple Records, 1985)
 * The Living Wood (first released by Green Linnet, 1988; reissued by Black Crow 1989; re-mastered and reissued by Old Bridge Music 1995, OBMCD07) - with guitarist Chris Newman
 * Out Of Court (Old Bridge Music OBMCD03, 1991) - with guitarist Chris Newman
 * The Carolan Albums (Old Bridge Music OBMCD06,1991) - with guitarist Chris Newman
 * Live In The Highlands (Old Bridge Music OBMCD08,1995) - with guitarist Chris Newman
 * Dialogues / Agallaimh (Old Bridge Music OBMCD014, 2001) - with guitarist Chris Newman
 * Firewire (Old Bridge Music OBMCD017, 2007) - with guitarist Chris Newman
 * Heartstring Sessions (Old Bridge Music OBMCD018, 2008) - with guitarist Chris Newman, fiddler / singer Nollaig Casey and guitarist Arty McGlynn
 * Christmas Lights (Old Bridge Music OBMCD20, 2013) - with guitarist Chris Newman
 * Sibling Revelry (Old Bridge Music OBMCD22, 2015) - with her sisters, fiddler / composer / singer Nollaig Casey and fiddler / singer Mairéad Ní Chathasaigh (The Casey Sisters)

Books

 * The Irish Harper (Vol. 1 and Vol. 2)

title: Máire Ní Chathasaigh


text:
User talk:Wikiwikifresh

Welcome to the Wikipedia
Here are some links I thought useful:

 * Tutorial
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Feel free to contact me personally with any questions you might have. The Village pump is also a good place to go for quick answers to general questions. You can sign your name by typing 4 tildes, like this: ~.

Be Bold!

[[User:Sam Spade|Sam Spade Wants you to vote!]] 23:56, 9 Dec 2004 (UTC)

title: User talk:Wikiwikifresh


text:
1814 in rail transport

July events

 * July 25 – George Stephenson puts his first steam locomotive in service, the Blücher for Killingworth Colliery on Tyneside in England.

January births

 * January 21 – Wendel Bollman, American designer of the Bollman Truss Railroad Bridge (d. 1884).
 * January 30 – Ferdinand Schichau, German mechanical engineer and founder of locomotive manufacturing company Schichau-Werke, is born (d. 1896).

May births

 * May 26 – Wilhelm Engerth, German steam locomotive designer (d. 1884).

September births

 * September 11 – John Ramsbottom, superintendent of the Manchester and Birmingham Railway (d. 1897).

Unknown date births

 * Andrew Barclay, Scottish steam locomotive builder (d. 1900).

title: 1814 in rail transport


text:
User talk:Timmenzies

Unverified images
Hi! Thanks for uploading the following image:

 * Image:Im0108aS.jpg

I notice it currently doesn't have an image copyright tag. Could you add one to let us know its copyright status? (You can use if you release it under the GNU Free Documentation License,  if you claim fair use, etc.) If you don't know what any of this means, just let me know where you got the imagesand I'll tag them for you. Thanks so much. [[User:Poccil|Peter O. (Talk, automation script)]] 23:58, Dec 9, 2004 (UTC)

P.S. You can help tag other images at User:Yann/Untagged_Images. Thanks again.

title: User talk:Timmenzies


text:
Talk:Switchblade

Definitions
Is a flick-knife a switchblade or a gravity knife? That is to say, is it a "flick" knife because it flicks out when the button is pushed (implies switchblade), or because you need to give it a flick to make it work (implies gravity knife)? I am grateful that I have no direct knowledge of this subject: can any experts here clarify which is the correct term? -- Karada 23:58, 9 Dec 2004 (UTC)

 * I'm certainly no expert but to me as a speaker of British English a flick-knife is a knife which opens by means of a spring released by pressing a button, intended as a weapon. OED is perhaps ambiguous but Merriam-Webster, Collins, Chambers and Longman all agree with the above. Harry 02:20, 10 Dec 2004 (UTC)

I would like to point out that "Switchblade" is a perjorative term for an automatic opening knife. That is the actual term for these types of knives, in the spirit of accuracy this article should probalby have its title changed to Automatic Opening knife, with Switchblade redirecting to it and being noted as a perjorative term. In Britain a flick knife is almost exclusively, a folding knife with a spring driven opening mechanism. The type of spring opening knife where the blade comes straight out the end is more commonly known as a stilleto.--Ykraps (talk) 15:12, 31 October 2010 (UTC)
 * Stilettos are not very common in Europe because they frequently go wrong and are difficult to fix. They are however ambidextrous whereas the side opening knife is not. The folding variety can be opened with the other hand but the button has to be depressed with the side of the forefinger as opposed to the thumb. This is much trickier to do.--Ykraps (talk) 15:28, 31 October 2010 (UTC)

Should the "Ger." behind "Sprenger" stand for German? If so, I will gladly put in a correct German word :) --dp  — Preceding unsigned comment added by 178.203.22.233 (talk) 14:19, 24 June 2011 (UTC)
 * It's more a difference in spelling of Schrade's pushbutton knife, called Springer or Sprenger based on various references. I have edited it.Dellant (talk) 16:14, 8 July 2011 (UTC)

Legality
Shouldn't there be something here about the legality of switchblades? I'm not sure what the actual laws are, but it's worth noting. Eldamorie 01:29, 1 May 2005 (UTC)
 * I agree. I had thought three was something at Knife, but it's just "Automatic knives (switchblades) are almost universally banned from civilian carry if not possession" which is better than nothing and sufficient for the entry Knife, but it would be good to have something more detailed at this more specific headword (Switchblade). Flapdragon 20:15, 1 May 2005 (UTC)
 * I'm working on an add on of the legality of switchblades in the U.S on a state by state basis: Do you all think that it would be appropriate to include in this article?
 * The legality section should probably be removed or edited down severely. Wikipedia is not an authoritative source on law and trying to keep this article current on individual state laws shouldn't be within the scope of the article not to mention could possibly open up liability issues. My suggestion is instead have the table provide links to the state departments that WOULD be the authoritative source. 69.134.162.135 (talk) 21:47, 21 December 2011 (UTC)

Legality Section needs Encyclopedic tone
Legality section seems to be written in the first person, and needs a more formal encyclopedic tone of voice. Gryffon 01:58, 24 March 2007 (UTC)

Nevada legality

 * I think that including the legality of switchblades in the US by state would be a great idea! If possible, find out the legality in other countries as well. Have at it! Boneheadmx 02:57, 31 December 2005 (UTC)

California legality
California Penal Code states that switchblades of length 2" and less are legal, however all swithcblades are banned from import, and must be fabricated in California. Also, perhaps include information on how assisted-opening folding knives (such as knives that use S.O.G.'s SAT technology) are not considered to be switchblades?  There's plenty of information here: http://www.equalccw.com/knifelaw.html#SECTION%20ONE 05:03, 17 March 2006 (UTC)

Soviet Union and Russian Federation legality
illegal —Preceding unsigned comment added by 178.184.160.85 (talk) 16:27, 6 November 2010 (UTC)

United Kingdom Legality
I've corrected the section on UK switchblade knife law. The maximum legal for a (folding, non-locking) knife to be legal to carry in public is 3", not 4". Wardog
 * "And also all knifes over 1 inch are taken out of the hands of the people as well as all blowguns and firearms.(totaly unfair)" - From the Australian legality section, really should be removed.

In the UK section it reads "although the knife would have to be pre-1959 vintage or its acquisition would be illegal." I note that neither the Restriction of Offensive Weapons Act 1959, nor the CJA 1988 explicitly outlaws the buying (or borrowing) of such a knife. How would its aquisition be illegal? I guess that buying such a knife could be regarded as the offence of inciting another person to illegally sell it...Also, I am not sure I agree 100% with "as long as it is held within the home". Certainly there are very few "reasonable excuses" for carring one in public, given that (under UK law) such knives are generally regarded as having no purpose other than as a weapon. But if you happen to own one, there are some circumstances when it might be reasonable (and therefore legal) to take it outside your home (some examples: moving house; putting your possessions into storage; transporting the knife to the police for destruction). But maybe these situations are to obscure to bother with... I agree that in general it would be a serious offence to have such a knife in a public place. TomH 01:39, 6 August 2007 (UTC) Also, I have made some minor changes to the links to UK laws. The links are now mostly to the actual legislation itself (on a government website) rather than to a third-party website which attempts to "explain" the law. I have removed the reference to the Knives Act 1997, which does not "ban" anything (it just restricts the way in which knives may be marketed). The 1959 Act does however outlaw the sale which effectively prohibits acquiring one in a legal circumstance after 1959. Perhaps it could be possible if inherited but having not looked into that angle I couldn't give any useful comment.TomH 02:03, 6 August 2007 (UTC)
 * A: The Restriction of Offensive Weapons Act 1959 (amended 1961) makes it illegal for anyone who " manufactures, sells or hires or offers for sale or hire, or exposes or has in his possession for the purpose of sale or hire or lends or gives to any other person" a automatic-opening (flick) knife or gravity knife as described in the Act, as of the date the legislation went into effect (13 June 1959). Under this law, any automatic opening or gravity knife given, sold, hired out to, exposed for sale, or lent to another after 13 June 1959 is an illegal act, and any offer of sale or hire of such a knife is illegal.  Addtionally, importation of such knives into the United Kingdom after 13 June 1959 is prohibited. Under a strict interpretation of the Act, it is not illegal to possess an automatic-opening or gravity knife as long as it the owner purchased it in the U.K. before 13 June 1959 and keeps the knife within the home or other private property, and does not transfer (sell, give, hire, lend) the knife to any other person. As the penalty provisions of the Act apply to the prior owner of the knife, not to the inheritor or subsequent purchaser, it is possible that a person living in the U.K. could acquire a automatic-opening or gravity knife made after June 1959 and keep it at home or on other private property without penalty to the new owner.  But, good luck convincing the Metropolitan Police with that interpretation.  They've even been seizing and destroying lock knives with manual thumb studs as "flick knives". Dellant (talk) 00:35, 30 October 2011 (UTC)
 * With the 2019 Amendments to the UK ROWA, this discussion is moot. Possession of a switchblade or flick knife, anywhere, including at home, is illegal within the United Kingdom. Dellant (talk) 21:17, 28 March 2022 (UTC)

Germany legality
Does anybody know when the law in Germany came into force? I was there in 1981 and purchased one with a 5.5" (140mm) blade quite legitimately.--Ykraps (talk) 16:06, 31 October 2010 (UTC)

Connecticut legality
The Connecticut law that is mentioned in the article says in no uncertain terms that switchblades are illegal to carry. The table then lists Connecticut as a state in which both possession and carrying are legal. There is something wrong, either the law is out of date or the table is wrong, I don't know which. Draganta 19:16, 30 September 2007 (UTC)
 * Second this. appears to indicate that it is illegal. Jochenroth 17:26, 23 October 2007 (UTC)
 * CT law has no restrictions on the mere possession or ownership of a switchblade, and it does not address sales or purchases. However, CT Code Sec. 943-53-206 defines certain knives as dangerous weapons and, with minor exceptions, makes it illegal to carry them on one's person or in a vehicle. Under the law, dangerous weapons are (1) dirk knives, (2) switch knives, (3) stilettos, (4) any knife that has an automatic spring release device that releases a blade from the handle longer than one and one-half inches, and (5) any knife that has a blade with an edged portion four inches or longer. Dellant 18:29 15 April 2019

Pennsylvania legality
I have updated Pennsylvania's possession column in the State table to reflect that automatic knives are legal if owned solely as curios per PCS Title 18, Chapter 9, Section 908 (Prohibited Offensive Weapons): "It is a defense under this section for the defendant to prove by a preponderance of evidence that he possessed or dealt with the weapon solely as a curio or in a dramatic performance..."

Florida legality
Thanks to Jeb Bush and Florida staute 790.225, F.S., Florida allows for people to carry switchblades.
 * http://election.dos.state.fl.us/laws/03laws/ch_2003-082.pdf
 * http://www.hsmv.state.fl.us/Bulletins/dec.pdf
 * http://www.flsenate.gov/data/session/2003/House/bills/billtext/pdf/h1227er.pdf --68.207.206.69 07:19, 9 January 2007 (UTC)
 * Switchblades weren't illegal in FL, except for a brief time after State of Florida v. Darynani set bad case law precedent for the state, on appeal. It was decided to be best to have the Legislation make 790.225 more explicit so activist judges couldn't again claim the law implied something it didn't. The original wording of 790.225 only banned possession of "self-propelled" knives (a term coined by the FL lawmakers), with a description of what are generally called "ballistic" knives. The use of the word "projectile" in the original wording would have made it impossible for a rational person to believe a common switchblade fit the description, but the appellate court obviously had a personal agenda. — Preceding unsigned comment added by WeaponGuy (talk • contribs) 23:31, 16 February 2011 (UTC)

Arizona legality
IANAL, but I seriously doubt that the Arizona courts consider a switchblade to be a "pocket knife" as meant in ARS 13-3102. If they don't, then one would have to have a concealed weapons permit to carry one concealed, as in Florida (open carry would require no permit.) 68.226.29.49 (talk) 20:56, 24 August 2009 (UTC)
 * AZ Statute 13-105 (Definitions) 15. "Deadly weapon" means anything designed for lethal use, including a firearm. Nowhere in AZ or FL statutes is a switchblade described as a "deadly weapon". This assumption by people (mostly police) that switchblades are intrinsically "deadly weapons" makes no sense. AZ doesn't require the carrier to be 21 and FL doesn't require a permit if concealed, despite the claims by many who speak from opinion rather than knowledge. Please cite any AZ law that even mentions "switchblade", a synonymous term, or some definition that describes a switchblade. Of course, there is no law that will grant permission to carry a switchblade, which is usually the required evidence of people who invent laws in their own minds. Laws don't work that way: They tell you what you must do and what you can't do; almost never what you can do if you want. — Preceding unsigned comment added by WeaponGuy (talk • contribs) 23:15, 16 February 2011 (UTC)
 * Your analysis is not entirely correct. In many states (including Arizona prior to 2010), poorly-drafted criminal statutes with broadly-defined and overly inclusive terms like "deadly weapon" (A.R.S. 13-105(15): "a deadly weapon is ANYTHING designed for lethal use, including a firearm") can easily result in a prosecution for carrying concealed in public a knife with arguably offensive features, such as a dagger or a stiletto switchblade; appellate arguments that such overly inclusive terms are unconstitutionally vague have gone nowhere in most jurisdictions.  Furthermore, Arizona case law contains numerous examples where the State Supreme Court freely borrowed commonly-accepted definitions of terms from the case law of other states or even the dictionary to determine their accepted meaning (see State v. Knapp, 114 Ariz. 531, 543, 562 P.2d 704, 716 (1977).  Given this practice, it would not be unforseeable for the Arizona State Supreme Court prior to 2010 to uphold a definition of a dagger- or stiletto-type knife such as the stiletto switchblade (a knife design with admittedly few practical uses besides that of weapon) as a 'deadly weapon.'   Fortunately, there is no need to debate this any further, since Arizona criminal statutes pertaining to the carrying of knives as concealed deadly weapons (13-3102, 13-105, and 13-3112) were changed dramatically by the passage of legislation in 2010 (S.B. 1108) authorizing the carrying of concealed deadly weapons without a permit (see: Arizona S.B. 1108).  The new law permits concealed carry of knives that MIGHT conceivably be deemed by an Arizona prosecutor or court to be deadly weapons under the very broad definition of A.R.S. 13-105(15) by those over 21 years of age.  To qualify for this exemption, the owner must be an adult and not be engaged in the commission of a serious offense, violent crime, or felony, must not be a prohibited possesssor (convicted felon or person court ordered for mental health treatment whose right to possess firearms has not been legally restored), must not carry the deadly weapon onto certain properties (schools, nuclear and hydroelectric power plants, polling places, public establishments and events prohibiting the carrying of deadly weapons, etc.), must not knowingly possess a defaced deadly weapon, must not use the weapon in the commission of any felony or in furtherance of an act of terrorism, and must accurately disclose that he is carrying a concealed weapon when asked by a law enforcement officer.  With these statutory changes the argument over whether an automatic knife or switchblade could be construed by a aggressive prosecutor as a 'deadly weapon' instead of a 'pocket knife' should largely be resolved. Dellant (talk) 14:26, 21 June 2011 (UTC)

Virginia Legality
It says "Illegal for black people" and gives a link to the section of law. However, it does not say that at all in the law cited. Methinks someone is having fun by putting that in there —Preceding unsigned comment added by BarbarianPhilosopher (talk • contribs) 04:57, 17 March 2009 (UTC)

Colorado legality
Only 49 states? —The preceding unsigned comment was added by 206.53.16.70 (talk) 04:54, 12 May 2007 (UTC).

Massachusetts legality
I was just reading through the MA law, and I wonder if "illegal" is a proper interpretation as the law clearly states: "No person having in effect a license to carry firearms for any purpose, issued under section one hundred and thirty-one or section one hundred and thirty-one F of chapter one hundred and forty shall be deemed to be in violation of this section." My reading of that doesn't jive with simply saying "illegal" —Preceding unsigned comment added by 97.107.131.163 (talk) 17:19, 15 July 2009 (UTC)

South Dakota legality
The Law cited For South Dakota In This Article Pertains To Ballistic Knives, Which Are Illegal In All 50 States Under Federal Law. Switchblades Are Perfectly Legal In South Dakota And Are Sold In Many Knife Shops All Over The State. —Preceding unsigned comment added by 24.230.47.21 (talk) 05:04, 12 May 2010 (UTC)
 * The Article For South Dakota Has Been Changed From Illegal To Legal, Based On Review Of South Dakota Law Pertaining To This Type Of Weapon, The Ballistic Knife Is The Only Knife On Record As Actually Being Illegal In This State, Butterfly Knives, Stiletto, Gravity, OTF Knives, And Pantographic Knives Are Also Legal And Sold In The State Of South Dakota. —Preceding unsigned comment added by 24.230.47.21 (talk) 06:16, 12 May 2010 (UTC)

Ohio legality
The state laws table in the article says "Legal - only ballistic knives are addressed in state law - State Code: § 2923.12". However, this is incorrect. From ORC § 2923.20 "Unlawful transaction in weapons" at http://codes.ohio.gov/orc/2923.20: "(A) No person shall: ... (3) Manufacture, possess for sale, sell, or furnish to any person other than a law enforcement agency for authorized use in police work, any brass knuckles, cestus, billy, blackjack, sandbag, switchblade knife, springblade knife, gravity knife, or similar weapon...." and goes on to indicate a violation of (A)(3) is a second-degree misdemeanor.

IANAL (yet) so I'm not even going to try to interpret this. But I will say that cutlery shops here in Ohio do not sell any kind of automatic knife to civilians, but only to authorized law enforcement & military personnel. —Preceding unsigned comment added by Wabofiur (talk • contribs) 18:46, 24 July 2010 (UTC)

Why So Controlled?
Why are switch blades so controlled and in many cases illegal in the United States? A country where it is legal to purchase guns (some states are even okay wit the purchase of automatic rifles), it seems a bit strange to me. I live in California and own a 45 inch sword (with a 35 inch blade). Why would a switchblade knife be illegal when a gun and sword are fulyl legal? This makes no sense. 04:47, 22 June 2006 (UTC)
 * I guess it's because switchblades are easily hidden, unlike a sword. Unlike a gun, you don't need to load them(giving people the chance to react). But it is pretty dumb that they don't allow switchblades. I tried to buy one when I was 13(as a collector's item, not to kill someone, don't worry), and they wouldn't let me. 08:26, 22 June 2006 (UTC)
 * Well in that case they should ban folding knives since most folding knives are easily hidden. Smaller fixed blades are easy to conceal as well. Zachorious 21:41, 28 June 2006 (UTC)
 * The main reason switchblades are so restricted in the United States is for juvenile crime prevention. Look at films such as "The Outsiders," for example.  It terrifies some (mostly elderly) hoplophobes to think that there are young people who own and would like to own such things.  The mindset involved in restricting such items is similar to the mindset involved in regulating the dreaded "assault weapons."
 * It allows politicians to appear tough on crime, and in most cases, that's all that matters.
 * That's it, essentially. Switchblade laws in the US almost uniformly originate in the "juvenile delinquency" scares of the 1950's (automatic knives have been in this country since the mid 19th Century, at latest, and were originally marketed as "ladies' knives", because they could be opened without damaging one's manicure).  Movies depicted the classic Italian stiletto as the preferred weapon of the juvenile delinquent, and massive public opinion led to a well-meaning but ultimately absurd federal law prohibiting the import or interstate traffic in automatic knives, and most states passed their own bans on ownership or carrying (not all--it's still legal to carry autos in Florida, for example).  In most US states, a private citizen with no criminal record and a clean mental health record can not only own, but also carry a handgun, but even licensed handgun carriers can't carry automatic knives.  Very few people pretend this makes sense.
 * If you want the official rationale, I've been told that police groups support switchblade bans because they don't want criminals to be able to quickly open a palmed knife when the cops order them to put their hands up. In addition, we often have laws intended to restrict access to _cheap_ weapons (see the handful of US laws intended to curb sales of "Saturday night specials"), and a cheap switchblade costs less than a cheap gun.  These arguments don't look very persuasive when you consider that criminals still sometimes use expensive automatic pistols (plus the black market markup), and the fact that non-automatic one-handed knives are legal to carry almost everywhere, but remember that these laws are based on fear; weapon prohibitions rarely make sense once you get past the fear.216.52.69.217 15:33, 30 August 2006 (UTC)
 * Switchblade knives are no more sharp, deadly, or dangerous than any of the kitchen knives, steak knives, pocket knives, or fixed blade hunting knives that have been sold legally in department stores for the longest time. The only real reason that laws even started getting passed against switchblade knives is because they were used by actors in the fight scenes of movies like "Rebel Without a Cause," and these movies first came out back in 1955. People were so much more impressionable by movies and TV shows in those days. There were no statistics back then to even show that switchblades were being used in any crimes, but somehow, certain politicians back in the late 1950's felt that once switchblades were banned, this would solve the problems of teenage delinquency and street gangs. What a joke that all turned out to be!
 * Seriously - the time has come for all of the laws against switchblades to be repealed. Kepiblanc (talk) 21:55, 23 July 2010 (UTC)

Use for switchblades
Switchblades are a general term, there are weapons, and non-weapons. American military switchblades are not weapons, and are used to cut parachute lines if only one hand is free. And the womens sewing kit automatic is based on 1920's newspaper advertisements by the schrade knife company.71.126.33.251 (talk) 10:44, 23 May 2008 (UTC)
 * Many handicaped people rely on them because they lack the dexterity to open a normal pocket knife. They also have uses in sports like parachuting. My brothers best buddy's chute got tanged so he pulled out his swichblade and cut the chute free as he was falling to the ground. If he had to manualy open it he said he would not have lived to tell about it. Mountain climbers and rapellers also find them handy.--68.207.206.69 07:27, 9 January 2007 (UTC)
 * Actually, they were invented so women could open a knife without breaking their fingernails. It was movies like West Side story that cast them in a negative light and lead hoplophobes in Congress to ban them. --Mike Searson 05:32, 19 December 2006 (UTC)
 * Oh, why isn't that in the article as "Uses", and what would a women do with a switchblade, I think it would be self-defence, get the dirt out of the underneath of their nails? I think it was used like a pocket knife, and i kind of blew the kiling people thing out of proportion. Ace Fighter 19:35, 21 December 2006 (UTC)

People carry knives for many reasons, at one time many more people carried them than they do in this politically correct world we now live in. As switchblades became bigger they were used by the military as chute knives, etc.
 * Still most people use knives to cut their food, open boxes, cut rope, etc. I even used a Strider folder the other day as a pen knife to fix a MontBlanc Fountain pen for someone!

--Mike Searson 05:55, 22 December 2006 (UTC)
 * Nice! thanks for that. hey I have a pocket kinfe, similar to a swiss army knife only a cheaper make, I use it to cut paper, slice an apple, open bottles. Ace Fighter 16:57, 22 December 2006 (UTC)
 * I carry mine everywhere. Ace Fighter 16:59, 22 December 2006 (UTC)

Is this a wikipedia entry about Switchblade legality or switchblades?
Over 80% of this article has nothing to do with switchblades other than discussing the history of their legality. What about when it was invented? —Preceding unsigned comment added by 68.88.195.51 (talk) 20:22, 14 October 2007 (UTC)
 * Or how they work? I'm curious to know how they work (particularly double action out-the-front switchblades) and a decent search of the Internet has yielded no results for me.  I ended up buying one to disassemble and study, and I'll put my findings in the article. 69.115.160.94 (talk) 00:21, 25 February 2008 (UTC)
 * ANSWER - How they work is a big can of worms, if someone adds a paragraph describing a DA-OTF mechanism (there are two, top button and side button), then you have to show a single action side cock, single action tail cock,single action trap door, a lever action, a lockback, a picklock, a button lock, a press button, a flylock, it would get way way complicated. Before you add this stuff to this article, consider a spin off article for each mechanism.Jerryk50 (talk) 08:43, 23 May 2008 (UTC)
 * The folding type of switchblade common in Europe has a very simple mechanism. Running parallel with the spine and fixed at the butt, is a tapering steel bar which is depressed by the blunt part of the blade (ricasso) when it is closed. A pin locates in an indentation on the ricasso and keeps the knife closed. Pushing the button lifts the pin and allows the blade to flick out. The blade automatically locks in the open position because another pin on the back of the blade engages with a hole on the spine of the knife. Pushing down on the guard lifts the spine and releases the blade so it can be closed.--Ykraps (talk) 15:58, 31 October 2010 (UTC)

History of the Switchblade
This section really needs a rewrite. Having a link in the section heading seems to be against proper format, and the overall wording of the section is too conversational. Also, the link at the bottom of the section is yelling at me. If no one else can do it, I guess I can bash something out. --Farfromhere (talk) 03:47, 17 May 2008 (UTC)
 * I added to the history from 1700's to 1920, and tried to sound factual, not conversational, I hope to add illustrations of toledo knife, D'Estang knife and Campobasso knife, I edited the part about "switchblade bad reputation" to sound more encyclopedic. I took out one sales site link, but did not double check all other links..Jerryk50 (talk) 08:36, 23 May 2008 (UTC)
 * History section completely rewritten and thoroughly referenced as of August 2011.Dellant (talk) 23:09, 29 October 2011 (UTC)

Collectors terms
I added collectors terms to be specific for switchblade collectors, & UNIDENTIFIED, added ATS34 steel, damascus, teflon which are steel types, not specific to switchblades, and also added an offsite link to a sales site which I removed. which was bragging about ATS34 steel, (common 300 series cheap stainless) not the best knife steel. ATS-34 Japanese made trade name stainless considered the equal of 154CM) Its great for you to contribute, but watch the sales hype, it's supposed to be encyclopedic. If you want to know about knife steels, do not redirect to a sales site, reference a good site, like Engnaths http://www.engnath.com/public/manframe.htm  Jerryk50 (talk) 05:47, 24 May 2008 (UTC) Also, I -Jerryk50- logged on, june 8, found a section removed by Thumperward and and I did not understand his explanation found in the edit history (QuoteThumperward, "multiple issues. rm a wholly OR section on alternative names. tidy endnotes". So I -Jerryk50- tried to find where it was moved to, but could not. I will not re-insert it into the article, if someone removed it, but I will add a link to another page where collectors terms, which may or may not be limited to -alternative names- Jerryk50 (talk) 22:06, 8 June 2008 (UTC).

Title 15 USC 1244 US Law
Someone wrote a bad summary, it is still not changed, they said switchblades (USC 1244) CAN be shipped by common carrier. This is not correct, it implies commerce, the section USC (1244)says you can not send via U.S.Postal service, that there are penalties for people trying to mail though the U.S.Postal service, and penalty exceptions will be made for common carriers during the course of normal business. (summary) a Fedex or UPS employee wont be arrested if he has a truck full of automatics. although shipping to an authorized dealer is permissable, the article is slightly misleading, as if anyone can mail order via common carrier.Jerryk50 (talk) 12:47, 24 May 2008 (UTC)

Are the anti-switchblade laws still being enforced?
Switchblade knives are on sale even on amazon.com, just search amazon for "stiletto knife" or "otf knife". So how does amazon allow this if these knives are supposed to be illegal? Then there are websites like bladeplay.com which sell many automatic knives and ship them via USPS which is also supposed to be illegal. --Auspx (talk) 02:15, 9 September 2008 (UTC)
 * Switchblades are legal in many US states. The Federal ban is a very confusing piece of law to anyone who's not a lawyer, but it only bans possession in Federally-administered territories, like Washington DC. --68.32.227.91 (talk) 05:26, 14 June 2009 (UTC)

Switchblades in movies
I just saw "The Wild One" starring Marlon Brandon from 1953. (1 hour 19 minutes version) As far as I can see there is not a single scene involving a switchblade, as stated in the article. —Preceding unsigned comment added by 84.202.26.10 (talk) 01:29, 28 July 2009 (UTC)

Cleaned up sections of questionable relevance
There is a lot of good information here, but it seems to cross the line in spots from informing to advocacy. Therefore, I removed the sections not pertinent to the article, the majority of which are the references to "AKTI", which is apparently a knife advocacy group.CuddlySatan (talk) 02:10, 7 August 2009 (UTC)

Proposal for US State law table
I have a suggestion for the table currently in the article. I feel it is incomplete as legality within a state is more than just possession and carry. It is my observation that knife legality in general has four areas, not two. They are possession (the mere owning or having control of said knife), commerce/trade (restrictions on the selling of the knife), open carry, and concealed carry. I propose that we expand the existing table to include these columns.Legitimus (talk) 17:04, 14 December 2011 (UTC)

Austria
I have extensively revised the section on switchblade legality concerning Austria. There were numerous factual errors. I am an Austrian lawyer, and while I'm happy to discuss any changes, please do not revert without discussion. IGreil (talk) 11:57, 14 October 2012 (UTC)
 * Please do not remove referenced material from the article.Dellant (talk) 15:41, 3 June 2013 (UTC)

Russia
Hello everybody! I'm user of Russian Wikipedia. I've written information about legality of switchblades in Russian Federation, and put links to the countries in the list. If you have something to tell me: wright here. --Shtirbo (talk) 20:40, 25 October 2013 (UTC)

Update to Legality in Texas
As I'm sure you've heard by now thanks to numerous article headlines about being able to "open-carry a sword in Texas", House Bill 1935 has now officially made it legal to carry any blade over 5.5 inches in public places. Thus, the current status that states a switchblade is legal in Texas, "As long as blade is not a dagger, dirk, or stiletto or has a blade length of over 5.5 inches," is no longer valid.

Here's the link to the act itself, followed by a news source which explains it in more manageable terms: http://www.legis.state.tx.us/tlodocs/85R/billtext/html/HB01935I.htm http://www.gosanangelo.com/story/news/2017/08/30/texas-open-carry-sword-law-takes-effect-sept-1/608759001/ Crossark (talk) 02:13, 2 September 2017 (UTC)

the section about Hawaii legality is wrong. It cites to H.R.S 134-51. Switchblades are illegal pursuant to 134-52 See https://law.justia.com/codes/hawaii/2012/title-10/chapter-134/section-134-52 — Preceding unsigned comment added by 24.25.200.36 (talk) 02:54, 21 October 2018 (UTC)

OTF blade shapes
First, the captions on the photos on the top read like ads, or at best someone showing off their prized knives; I don't think detailed brand name, size, type, model name, blade material, etc, it necessary. Just "an example of two automatic knives, one an OTF and one a folder". The other can say "another example of a folding automatic; note the activating button". The rest is just relevant to knife fans and sounds like it was written by someone hoping to sell a few. Next, it says "Additionally, because of the way that the blade folds into the handle, side-opening knives are typically more limited in their blade shapes. " I dispute this. Why on earth would a FOLDER be more limited in blade shapes? Right above it they show a picture of a pair of folders, and it's the FOLDER in the photo that has a forward curved blade. An OTF can only have one blade shape: straight and relatively slender. It needs to slide out of a small opening in the front of the handle. A folder can be any shape that can be accommodated within the handle, which covers a wide variety of shapes, second only to fixed blade knives. It would appear that someone just mixed the two up. Also, I'm sure it varies by nation, and is all slang anyway, but a "flick" knife ought to cover any sort of folding knife that can be flicked open with one hand, which is the majority of NON automatic models sold today. You need to "flick" the knife to make it open, but it can be opened rapidly and with one hand. I wonder if someone is confusing automatic knives with the non-autos that can LOOK like autos to the layperson. Second, a "switchblade" is a specific TYPE of automatic knife. It requires, under US law, that the blade be unlocked by a switch or lever; this is why Kershaw can make and sell their "Speedsafe" knives in Walmart in most US states. There is no switch, one just starts to open the blade with the thumb stud or "flipper" like any other one-handed folding knife, when the spring takes over and flips it out much like an automatic. But under law it is NOT a "switchblade"....except in states that define them as "spring assisted knives". Under Federal Law they are legal and not switchblades. There are also "gravity knives", which like switchblades originally had a very specific meaning, referring to large, scary combat knives with heavy OTF blades that would drop out the front of tne handle by gravity when a button was pushed. Some states like NY have "imaginitivly reinterpreted" this law to make it cover ANY knife that can be flicked open with one hand, with or without springs. Meaning that 70% of folding knifes sold in Walmart in most US states will get you a felony weapons charge in VY state, in spite of them having nothing to do with the "gravity knives" the law was written for. Obviously Speedsafes are right out. So gravity knives, switchblades, Speedsafes are all types of AUTOMATIC KNIFE, but they are not all "switchblades". This article should be moved to a more suitable title. Also, a "stilletto", or "Italian stilletto" is NOT a "switchblade". While the "classic" or stereotypical switchblade was in the form of a long, slender bladed knife that was largely made in Italy and called a "stiletto", you could get the same knife in regular folding models. It's also not actually a stiletto, which is a slim, edgeless dagger for stabbing, used to penetrate armor joints and chain mail.

Idumea47b (talk) 03:20, 19 March 2020 (UTC)

Can't understand this part
"Under a strict interpretation of the Act, it is legal to possess an automatic-opening or gravity knife made before 13 June 1959 if it is held by the original owner within the home or other private place and is not transferred to any other person.[41] As the penalty provisions of the Act apply to the prior owner of the knife, and not to the inheritor or subsequent purchaser, it is possible that a person living in the UK could acquire an automatic-opening or gravity knife and keep it at home or on other private property without penalty to the new owner, though a zealous prosecutor might attempt to level a charge of abetting or facilitating an offence by the knife's former owner as a consequence of acquiring the knife in a prohibited post-1959 transaction." I'm not sure what this is trying to say. It appears to maybe be saying that a person could maybe, possibly, legally obtain a switchblade by moving into the home of a person who had retained one legally by being grandfathered in under the original law....but that the person who sold you the home and the knife could be charged with abetting a felony for selling it to you? I really can't make it out. It also sounds suspiciously like original research or opinion, and of a dangerous sort, kind of like seeing Soveriegn citizen theory advocated on a wiki page. The only citation is the text of the law itself, not any expert legal opinion or court case establishing precedent. Sounds problematic, and in any case needs to be explained better so a reader can understand it. Although now that I look at it again, maybe it's just saying "you can buy a knife off of a grandfathered person, and since the law only states penalties for the SELLER you MIGHT get away without being prosecuted while the seller MIGHT be prosecuted". I would be very wary of trying this myself, personally, and who is going to sell his precious knife he/she has kept since the law passed in 1959, knowing that THEY are the ones who take the risk? I am pretty sure that in this case the buyer would be absolutly prosecuted under the same rule that prohibits ALL other persons from owning automatic knives. Just because the knife in question was allowed to a specific person grandfathered in doesn't somehow magically mean that the law doesn't apply to that knife once it's transferred.

Idumea47b (talk) 03:36, 19 March 2020 (UTC)

 * Regardless of the exact meaning, (and whether it's correct), we WP-ers don't make up examples like this ourselves, but simply report on them if a Reputable Source has done so. Not the case here, so it's now gone. - Snori (talk) 06:47, 19 March 2020 (UTC)
 * With the 2019 Amendments to the UK ROWA, this discussion is moot. Possession of a switchblade or flick knife, anywhere, including at home, is illegal within the United Kingdom. Dellant (talk) 21:13, 28 March 2022 (UTC)

Sprenger, Springer?
If that is supposed to be another german term for a switchblade knife, I can assure you it is not. The terms "springen" and "sprengen" mean two very different things ("to jump" and "to blow up" as in "to make something explode"). The source given for that term, a book by Ragnar Benson, is american and is quoted applying the, correct, term "Springmesser". Should Benson actually have given the term "Sprenger" as a german term for such a knife, he is either misinformed or quotes a non-generalized use from local dialect. Alternatively, the term might(!) be in use in other european languages. Perhaps Swedish? Norwegian? Dutch? 2003:CA:3F0A:201C:C10B:4ED:FEC1:478 (talk) 16:53, 9 October 2022 (UTC) To make things worse, the term "Springer", as it is used by the source, refers to the family name of manufacturer Hubertus Springer used for products such as the "Springer Knife" (compare "Singer Sewing Machine"). That said, the mention of those terms might be considered unimportant.2003:CA:3F0A:201C:C10B:4ED:FEC1:478 (talk) 17:04, 9 October 2022 (UTC)

title: Talk:Switchblade


text:
Schreckstoff

In 1938, the Austrian ethologist Karl von Frisch made his first report on the existence of the chemical alarm signal known as Schreckstoff (fright substance) in minnows. An alarm signal is a response produced by an individual, the "sender", reacting to a hazard that warns other animals, the receivers, of danger. This chemical alarm signal is released only when the sender incurs mechanical damage, such as when it has been caught by a predator, and is detected by the olfactory system. When this signal reaches the receivers, they perceive a greater predation risk and exhibit an antipredator response. Since populations of fish exhibiting this trait survive more successfully, the trait is maintained via natural selection. While the evolution of this signal was once a topic of great debate, recent evidence suggests schreckstoff evolved as a defense against environmental stressors such as pathogens, parasites, and UVB radiation and that it was later co-opted by predators and prey as a chemical signal.

Background
Chemical alarm systems have been identified in a number of different taxa, including gastropods, echinoderms, amphibians and fishes. One of the most well-studied chemical alarm signals is schreckstoff, the use of which is widespread in the superorder Ostariophysi (e.g., minnows, characins, catfishes, etc.). About 64% of all freshwater fish species and 27% of all fish species worldwide are found in the ostariophysan superorder, which highlights the widespread use and importance of this chemical alarm system in fishes.

Schreckstoff in ostariophysans
The production of schreckstoff has been shown to be metabolically expensive and is therefore part of a conditional strategy that can only be employed by individuals with access to sufficient resources. One putative active ingredient in schreckstoff is hypoxanthine-3N-oxide (H3NO), which may be produced in club cells which will henceforth be referred to as "alarm substance cells". The nitrogen oxide functional group was found to be the main chemical trigger of antipredator behavior in receivers. Schreckstoff is a mixture, and fragments of a glycosaminoglycan, chondroitin sulfate, are able to trigger fear responses. The precursor polysaccharide is a component of mucus, and fragments are proposed to be produced during injury. Like schreckstoff obtained from skin extract, chondroitin sulfate activates a subset of olfactory sensory neurons.

Production of and responses to schreckstoff change over the course of ontogeny. For example, young brook sticklebacks (Culaea inconstans) are more likely to be caught in minnow traps that have been baited with conspecific skin extracts than adults. This result indicates young brook sticklebacks do not make the association between schreckstoff and the potential presence of a predator as readily as adults. Whether this association strengthens over time as a result of learning or physiological development remains unclear.

In addition to changes across ontogeny, the degree to which schreckstoff is produced varies within the breeding season. Male fathead minnows (Pimephales promelas) cease production of schreckstoff during the breeding season, but still exhibit antipredator behaviors in response to schreckstoff during this time. Schreckstoff production may be halted at this time because male fathead minnows often incur mechanical damage while building their nests. It would be detrimental to a male to produce schreckstoff while building a nest, as it would inadvertently repel females, thereby decreasing the likelihood of obtaining a mate. By ceasing schreckstoff production during the breeding season, males circumvent this problem. The cessation of alarm substance cell production appears to be controlled by androgens.

Hypotheses for the evolution of schreckstoff
A number of different hypotheses have been proposed for the evolution of schreckstoff. The first hypothesis is that the evolution of schreckstoff has been driven by kin selection. Support for this hypothesis would include evidence that individuals live in groups of closely related kin and that the release of chemical alarm signals increases the likelihood that related individuals will avoid predation. The second hypothesis, predator attraction, suggests the release of schreckstoff may attract additional predators which will interfere with the predation event, increasing the likelihood that the prey will escape and survive the attack. This hypothesis assumes predators will be attracted to schreckstoff and will interfere with one another either through competition for the captured prey or through predation of one another. It additionally assumes, despite the fact that the prey has already incurred mechanical damage, it is possible for the prey to escape and recover from the attack. Testing and validating these assumptions would provide support for the predator attraction hypothesis. The third hypothesis proposes that schreckstoff has an immune function, providing protection against pathogens, parasites and/or UVB radiation. For this hypothesis to be supported, a correlation between alarm substance cell production and the presence of pathogens and parasites would need to be observed. Direct evidence that schreckstoff inhibits the growth of aquatic pathogens and parasites would provide additional support for the immunity hypothesis. Another hypothesis is that schreckstoff is a breakdown product of mucus and club cells, induced by injury. Selection for the alarm response is primarily at the level of the receiver.

Kin selection hypothesis
One of the first hypotheses for the evolution of schreckstoff centered on W.D. Hamilton’s theory of kin selection. Under the theory of kin selection, the sender of the chemical alarm signal would be willing to incur the costs of sending this signal if the benefits to related individuals were sufficiently high. In a situation where the sender of the signal is paying great costs (i.e., it releases the chemical alarm signal because it has incurred potentially mortal mechanical damage), the benefits to closely related kin would have to be great. Under the framework of kin selection, behaviors that are seemingly detrimental to the sender are selected because they benefit individuals that are likely to share alleles by common descent. In this way, the frequency of the sender's alleles in the next generation is increased by their presence in successful kin.

To apply kin selection theory to the evolution of schreckstoff, a number of conditions must be met. First, evidence must exist for the release of schreckstoff by the sender confers benefiting the receivers. Second, it must be shown that individuals in the order Ostariophysi associate mainly with family members. If either of these two assumptions is violated, then the kin selection hypothesis would not be supported.

Some evidence exists in support of the first assumption that the release of schreckstoff confers quantifiable advantages to the receivers of this chemical signal. A laboratory experiment revealed that fathead minnows exposed to conspecific schreckstoff survived 39.5% longer than controls when placed in a tank with a predatory northern pike (Esox lucius). This finding suggests schreckstoff increases vigilance in receivers, resulting in a quicker reaction time following detection of the predator.

The second assumption, that individuals in the order Ostariophysi associate with close family members, does not appear to be supported by empirical evidence. In shoals of European minnows (Phoxinus phoxinus), no difference in relatedness was found within and between shoals, indicating individuals are not associating more closely with relatives than nonrelatives. Shoal composition has not been examined in all members of the ostariophysan order, and shoals composed entirely of family members may yet be discovered. Nevertheless, the finding that schreckstoff production is maintained in a species where the function is clearly unrelated to kin benefits provides strong evidence against kin selection as a mechanism for the evolution of schreckstoff.

Fathead minnows have also been found to produce fewer epidermal alarm substance cells (and therefore less schreckstoff) when in the presence of familiar shoalmates. The results of this study indicate one of two scenarios, neither of which is compatible with the hypothesis that schreckstoff evolved by kin selection. First, if schreckstoff evolved by kin selection, more epidermal alarm substance cells would be expected to be produced in the presence of kin than nonkin. This means familiar shoalmates in fathead minnows should be closely related kin and schreckstoff production should be increased when in shoals with familiar individuals. The study did not find this to be the case. Second, these results indicate individuals either do not associate with kin at all or production of schreckstoff varies depending on how familiar the focal fish is with the individuals with which it shoals. In conclusion, evidence does not support the hypothesis that schreckstoff evolved because it bolstered the inclusive fitness of the sender through increased survival of kin.

Predator attractant hypothesis
The predator attractant hypothesis proposes that the main purpose of schreckstoff is to attract additional predators to the area. According to this hypothesis, additional predators will interact with the initial predator, and these interactions will provide the sender with an opportunity to escape. A number of conditions must be met to support this hypothesis. First, schreckstoff must attract predators. Second, subsequent predators must disrupt the predation event, thereby increasing the probability that the prey will escape. Third, the sender must be able to recover from the mechanical damage incurred during the predation event.

A study provides support for the first condition that the release of schreckstoff must attract predators. This experiment revealed that schreckstoff extracted from the skin of fathead minnows attracted both northern pike (Esox lucius) and predatory diving beetles (Colymbetes sculptilis). Additionally, a natural study showed that predatory fish were seven times more likely to strike a lure baited with a sponge soaked in fathead minnow skin extract than a sponge soaked in either water or skin extract from a nonostariophysan convict cichlid (which presumably does not produce schreckstoff).

While the previous two studies provided examples of systems in which schreckstoff acts to attract additional predators, a system was found for which this was not the case. Spotted bass (Micropterus punctulatus) were exposed to skin (containing schreckstoff) and muscle (control, containing no schreckstoff) extracts from five different co-occurring prey species. The spotted bass were not attracted to any of the schreckstoff treatments. This result indicates schreckstoff does not always attract relevant predators in the area. Northern pike are an introduced species in many areas, so were not likely to be coevolving with fathead minnows during the evolution of the schreckstoff system. This system may be more ecologically relevant and little evidence suggests schreckstoff evolved as a predator attractant. In conclusion, the debate continues over whether or not the first condition for this hypothesis has been met.

The second condition that needs to be met in support of the predator attraction hypothesis is that additional predators must occasionally disrupt predation events, increasing the probability that prey will escape. In the northern pike/fathead minnow system, additional northern pike may interfere with a predation event in one of two ways. First, additional northern pike of the same size interfere with a predation event by coming into contact with the main predator (biting it, etc.). Second, additional pike of larger size attracted to schreckstoff may prey on the initial predator.

The probability that fathead minnows escape after being captured by a northern pike significantly increases when a second pike interferes with the predation event. The northern pike have an age-structured population biased towards younger, smaller individuals. If a younger pike attacks a fathead minnow and attracts an older, larger conspecific, then the younger pike may be at risk of cannibalism and will be inclined to release the prey to focus on escape. In regards to the second condition, additional predators do appear to disrupt predation events, increasing the probability that the sender will escape. The final condition, that individuals need to successfully recover from a predation event, appears to be satisfied. Support for this condition comes from the observation that many small fishes in natural populations exhibit scars, presumably from failed predator attempts.

While the evidence that schreckstoff attracts predators is mixed, studies indicate multiple predators will interfere with each other and prey can recover from predation events when they manage to escape. The extent to which predators are attracted to a predation event depends upon the speed at which schreckstoff diffuses through its aquatic environment, which in turn depends upon water flow parameters. This hypothesis indicates schreckstoff evolved as a way of increasing the probability of survival during a predation event and its role as a predator cue for conspecifics evolved subsequently. Supported by more empirical studies than the kin selection hypothesis, the predator attraction hypothesis remained popular for quite some time.

Schreckstoff as a possible defense against pathogens, parasites and UVB radiation
The final hypothesis posits that schreckstoff has an immune function and may be the first line of defense against pathogens, parasites, and/or UVB radiation. Evidence for this hypothesis is strong. A recent comprehensive study revealed that exposure to parasites and pathogens that penetrate the skin of ostariophysans stimulated the production of alarm cells. Additionally, increased exposure to UV radiation was correlated with an increase in alarm cell production.

The role of schreckstoff in immune response was further strengthened by the finding that skin extracts from fathead minnows inhibited the growth of Saprolegnia ferax (a water mould) in culture. In contrast, skin extracts from swordtails (Xiphophorus helleri), which are not believed to produce schreckstoff, increased S. ferax growth compared to controls. Cadmium, a heavy metal and an immunosuppressant in vertebrates, inhibits the production of alarm cells when fishes are infected with Saprolegnia. Furthermore, a follow-up study treated fathead minnows with cortisol, a well-known immunosuppressant, which significantly reduced alarm cell investment in conjunction with leukocyte activity. The results of these extensive studies strongly suggest schreckstoff's main function is to provide immunity against a number of environmental threats aimed at the fish's epidermis.

If schreckstoff evolved as a defense against pathogens, parasites, and UVB radiation, then the release of schreckstoff into the environment subsequently allowed for both predators and prey to exploit this system. Predators in some systems may use schreckstoff as a cue for an easy meal, either by disrupting the predation event to steal the prey item for themselves or by preying on the initial predator. Nearby conspecifics then exploit schreckstoff as a chemical cue, alerting them to the presence of a predator in the area.

Ecological considerations
The most convincing research to date indicates alarm substance cells serve as an immune system response and the ecological ramifications of this substance as a chemical alarm signal developed subsequently. This finding generates a number of interesting research questions. First, as mentioned earlier, males in many ostariophysan species cease production of alarm substance cells during the breeding season, presumably so females are not inadvertently repelled from the nest when males incur mechanical damage during nest building. In light of the immune hypothesis, alarm substance cells possibly are instead produced less during the breeding season because increased testosterone levels may decrease immune responses. Additionally, this finding indicates males are at a greater risk from UVB radiation, as well as parasite and pathogen infection, during the breeding season.

The role of schreckstoff as an immune response has additional implications in this age of increasing environmental change. Environmental stressors, including UVB radiation, pollution, and parasites, are increasing in the environment, and are likely to continue increasing over time. UVB radiation exposure is increasing due to decreases in stratospheric ozone, diseases are becoming increasingly important at both local and global scales, and pollutants, including heavy metals, are being introduced into ecosystems. If cadmium, the heavy metal affecting the fish's ability to produce schreckstoff in response to environmental stressors, increased in concentration in the environment, the immune response of many ostariophysan fishes would be compromised.

title: Schreckstoff