X265 - Wikipedia

HEVC/H.265 encoder X265

Other names	H.265, HEVC/H.265
Developer(s)	MulticoreWare
Initial release	2013 (11 years ago) (2013)
Stable release	4.1[1]  / 22 November 2024; 36 days ago (22 November 2024)
Repository	bitbucket.org/multicoreware/x265_git/src/master/
Written in	C++, x86 assembly
Standard(s)	High Efficiency Video Coding (HEVC)
Type	Video codec
License	GPL-2.0-or-later,[2] or optionally an on-request commercial license[3]
Website	x265.org

x265 is an encoder for creating digital video streams in the High Efficiency Video Coding (HEVC/H.265) video compression format developed by the Joint Collaborative Team on Video Coding (JCT-VC).[4][5][6] It is available as a command-line app or a software library, under the terms of GNU General Public License (GPL) version 2 or later; however, customers may request a commercial license.[3][7]

History

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x265 builds on source code from x264, an open-source video encoder for the previous MPEG video coding standard, H.264/MPEG-4 AVC. The project has licensed the rights to use the x264 source code.[3] Development on x265 began in March 2013.[7] MulticoreWare made the source code for x265 publicly available on July 23, 2013.[4][5]

The x265 project was initially funded by a small group of charter licensee companies that direct the development requirements and receive commercial licenses to use x265 in their products without having to release their products under the GPL 2 license.[3] In February 2014, x265 was integrated into the popular multimedia transcoding tool FFmpeg and its fork Libav.[8]

Version 1.0 was completed in May 2014.[9] The stable version (2.0) was released on July 14, 2016.[10]

Technical details

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x265 source code is written in C++ and x86 assembly.[3]

x265 supports the Main, Main 10, Main 12 and Main Still Picture profiles[11] of HEVC (including intra-only profiles), utilizing a bit depth of either 8 bits or 10 bits per sample YCbCr with 4:2:0, 4:2:2 or 4:4:4 chroma subsampling.[12] x265 supports most of the features of x264 including all rate control modes: Constant QP (CQP), Constant Rate Factor (CRF), Average Bit Rate (ABR), 2-pass or multi-pass and video buffering verifier rate control.[13] Visual quality algorithms include CU-Tree (the successor to x264's macroblock-tree), adaptive quantization, b-pyramid, weighted prediction and psycho-visual optimizations (psy-rd and psy-rdoq). A fully lossless mode is also supported. Temporal scalability is supported, allowing for a video to be encoded into a base layer HEVC bitstream that is half the frame rate of the input video frame rate, and an enhancement layer that can be decoded along with the base layer to enable playback at the full frame rate.

In April 2015, at the NAB Show in Las Vegas, MulticoreWare demonstrated high quality real-time 4K 10-bit HEVC encoding[14] at frame rates in excess of 60 FPS on a dual Intel Xeon E5 v3 server, occupying only one standard rack unit.

Quality and efficiency

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Judged by the objective quality metric VQM in 2015, x265 delivered video quality on par with the reference encoder of the royalty-free VP9 format that competes with HEVC.[15] A codec comparison from 2015 found x265 to be a leading HEVC implementation measured by SSIM metric.[16] In August 2016, Netflix published a comparison of x264, VP9, and x265 using video clips from 500 movies and TV shows using 6 different quality metrics and found that both VP9 and x265 have 40%–50% better quality at 1080p than x264. Netflix stated that with the VMAF metric (which closely mirrors human visual experience according to the author) x265 performed substantially (19% to 22%) better than VP9.[17]

Usage

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x265 can be invoked as a command-line app or integrated into another application through the application programming interface.[18][19]

Open-source adopters

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Open source software projects which utilize x265 for HEVC encoding:

• Avidemux[20]
• FFmpeg[21]
• HandBrake[22]
• Internet Friendly Media Encoder[23]
• MeGUI[24]
• OpenShot[25]
• ShareX[26]
• Shotcut[27]
• Staxrip[28]
• x265vfw[29]

Commercial adopters

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Commercial products that utilize x265 for HEVC encoding:

• BBright SLED-4K and SLED-HD Encoder[30]
• Blackmagic DaVinci Resolve Studio[31][failed verification]
• CloudApp
• Sorenson Squeeze Desktop Pro and Squeeze Server[32]
• Telestream Vantage Media Processing Platform[33]
• TMPGEnc Video Mastering Works[34]

• x265 HEVC Upgrade[35]

References

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1. ^ "Bitbucket". Retrieved 13 December 2024.
2. ^ "Bitbucket". bitbucket.org.
3. ^ a b c d e "x265 Mission Statement". Bitbucket. 2013-07-24. Retrieved 2013-07-24.
4. ^ a b Joel Hruska (2013-07-23). "H.265 benchmarked: Does the next-generation video codec live up to expectations?". ExtremeTech. Retrieved 2013-07-23.
5. ^ a b Chris Angelini (2013-07-23). "Next-Gen Video Encoding: x265 Tackles HEVC/H.265". Tom's Hardware. Retrieved 2013-07-23.
6. ^ "HEVC / H.265 Explained". x265. Retrieved 2022-02-13.
7. ^ a b "x265 Development Road Map". Bitbucket. 2013-07-23. Archived from the original on 2015-04-02. Retrieved 2013-07-23.
8. ^ Volker Zota (heise online), 14. 2. 2014: Videokodierung: HEVC/H.265-Encoder hält Einzug bei FFmpeg und LibAV
9. ^ "multicoreware / x265 / Commits — Bitbucket". bitbucket.org.
10. ^ "[x265] [ANN] x265 2.0 released". 13 July 2016.
11. ^ "Command Line Options — x265 documentation". Retrieved 2024-03-12.
12. ^ "Command Line Options — x265 documentation". Retrieved 2024-03-12.
13. ^ "x265 Documentation — x265 documentation". Retrieved 2024-03-12.
14. ^ "MulticoreWare demonstrates high quality 4K 10-bit real-time HEVC video encoding with x265". Design And Reuse.
15. ^ Jan Ozer, April 2015: The Great UHD Codec Debate: Google's VP9 Vs. HEVC/H.265
16. ^ Jan Ozer, November 9, 2015: Moscow State Releases First HEVC Comparison
17. ^ Ozer, Jan. "Netflix Finds x265 20% More Efficient than VP9 - Streaming Media Magazine". Streaming Media Magazine. Retrieved 2016-11-09.
18. ^ "Command Line Options — x265 documentation". Retrieved 2024-03-12.
19. ^ "Application Programming Interface — x265 documentation". Retrieved 2024-03-12.
20. ^ "Avidemux – News".
21. ^ "General Documentation".
22. ^ "HandBrake: Features".
23. ^ "x265 GUI Encoder with Internet Friendly Media Encoder!".
24. ^ berrinam (7 May 2023). "MeGUI". SourceForge.
25. ^ "OpenShot".
26. ^ "ShareX 13.1.0 - changelog". 2020-03-01.
27. ^ "Shotcut".
28. ^ "StaxRip".
29. ^ "x265vfw".
30. ^ "BBright – Ultra HD / 4K Video Products and Laser Light Sources". BBright.
31. ^ "DaVinci Resolve 16 | Blackmagic Design". www.blackmagicdesign.com. Retrieved 2020-07-17.
32. ^ "Squeeze Desktop Pro – Sorenson Media". Sorenson Media. Archived from the original on 2015-09-17. Retrieved 2015-07-22.
33. ^ "Video Workflow Automation Software – Vantage Workflow Features & Benefits – Telestream".
34. ^ "TMPGEnc Video Mastering Works 6".
35. ^ "x265 HEVC Upgrade". x265.

External links

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• Official website for the Open Source Project

v t e Multimedia compression and container formats
Videocompression	ISO, IEC, MPEG DV MJPEG Motion JPEG 2000 MPEG-1 MPEG-2 Part 2 MPEG-4 Part 2 / ASP Part 10 / AVC Part 33 / IVC MPEG-H Part 2 / HEVC MPEG-I Part 3 / VVC MPEG-5 Part 1 / EVC Part 2 / LCEVC ITU-T, VCEG H.120 H.261 H.262 H.263 H.264 / AVC H.265 / HEVC H.266 / VVC SMPTE VC-1 VC-2 VC-3 VC-5 VC-6 TrueMotion and AOMedia TrueMotion S VP3 VP6 VP7 VP8 VP9 AV1 Chinese Standard AVS1 P2/AVS+(GB/T 20090.2/16) AVS2 P2(GB/T 33475.2,GY/T 299.1) HDR Vivid(GY/T 358) AVS3 P2(GY/T 368) Others Apple Video AVS Bink Cinepak Daala DVI FFV1 Huffyuv Indeo Lagarith Microsoft Video 1 MSU Lossless OMS Video Pixlet ProRes 422 4444 QuickTime Animation Graphics RealVideo RTVideo SheerVideo Smacker Sorenson Video/Spark Theora Thor Ut WMV XEB YULS
Audiocompression	ISO, IEC, MPEG MPEG-1 Layer II Multichannel MPEG-1 Layer I MPEG-1 Layer III (MP3) AAC HE-AAC AAC-LD MPEG Surround MPEG-4 ALS MPEG-4 SLS MPEG-4 DST MPEG-4 HVXC MPEG-4 CELP MPEG-D USAC MPEG-H 3D Audio ITU-T G.711 A-law µ-law G.718 G.719 G.722 G.722.1 G.722.2 G.723 G.723.1 G.726 G.728 G.729 G.729.1 IETF Opus iLBC Speex Vorbis FLAC 3GPP AMR AMR-WB AMR-WB+ EVRC EVRC-B EVS GSM-HR GSM-FR GSM-EFR ETSI AC-3 AC-4 DTS Bluetooth SIG SBC LC3 Chinese Standard AVS1 P10(GB/T 20090.10) AVS2 P3(GB/T 33475.3) Audio Vivid(GY/T 363) DRA(GB/T 22726) ExAC(SJ/T 11299.4) Others ACELP ALAC Asao ATRAC CELT Codec 2 iSAC Lyra MELP Monkey's Audio MT9 Musepack OptimFROG OSQ QCELP RCELP RealAudio RTAudio SD2 SHN SILK Siren SMV SVOPC TTA True Audio TwinVQ VMR-WB VSELP WavPack WMA MQA aptX aptX HD aptX Low Latency aptX Adaptive LDAC LHDC LLAC
Imagecompression	IEC, ISO, IETF, W3C, ITU-T, JPEG CCITT Group 4 GIF HEIC / HEIF HEVC JBIG JBIG2 JPEG JPEG 2000 JPEG-LS JPEG XL JPEG XR JPEG XS JPEG XT PNG TIFF TIFF/EP TIFF/IT Others APNG AV1 AVIF BPG DjVu EXR FLIF ICER MNG PGF QOI QTVR WBMP WebP
Containers	ISO, IEC MPEG-ES MPEG-PES MPEG-PS MPEG-TS ISO/IEC base media file format MPEG-4 Part 14 (MP4) Motion JPEG 2000 MPEG-21 Part 9 MPEG media transport ITU-T H.222.0 T.802 IETF RTP Ogg Matroska SMPTE GXF MXF Others 3GP and 3G2 AMV ASF AIFF AVI AU BPG Bink Smacker BMP DivX Media Format EVO Flash Video HEIF IFF M2TS Matroska WebM QuickTime File Format RatDVD RealMedia RIFF WAV MOD and TOD VOB, IFO and BUP
Collaborations	NETVC MPEG LA Alliance for Open Media
Methods	Entropy Arithmetic Huffman Modified LPC ACELP CELP LSP WLPC Lossless Lossy LZ DEFLATE LZW PCM A-law µ-law ADPCM DPCM Transforms DCT FFT MDCT Wavelet Daubechies DWT
Lists	Comparison of audio coding formats Comparison of video codecs List of codecs
See Compression methods for techniques and Compression software for codecs

v t e Data compression software
Archivers with compression (comparison)	Free software 7-Zip Ark Expander FreeArc GNOME Archive Manager Info-ZIP KGB Archiver PAQ pax PeaZip XAD (decompression only) Xarchiver Zipeg ZPAQ Freeware Filzip LHA Lhasa (decompression only) StuffIt Expander (decompression only) The Unarchiver (decompression only) TUGZip ZipGenius Commercial ARC ALZip Archive Utility ARJ BetterZip MacBinary PKZIP/SecureZIP PowerArchiver StuffIt WinAce WinRAR WinZip
Non-archivingcompressors	Generic bzip2 compress gzip lzip lzop pack rzip Snappy XZ Utils zstd For code UPX
Audio compression (comparison)	Lossy AAC Fraunhofer FDK AAC Nero AAC Codec FAAC Helix DNA Producer MP3 l3enc LAME TooLAME libavcodec libcelt libopus libspeex Musepack libvorbis Windows Media Encoder Lossless ALAC FLAC libavcodec Monkey's Audio mp4als OptimFROG Shorten WavPack
Video compression (comparison)	Lossy MPEG-4 ASP 3ivx DivX Nero Digital FFmpeg HDX4 Xvid H.264 CoreAVC Blu-code DivX FFmpeg Nero Digital OpenH264 QuickTime x264 HEVC DivX x265 Others CineForm Cinepak Daala DNxHD Helix DNA Producer Indeo libavcodec Schrödinger (Dirac) SBC Sorenson VP7 libtheora libvpx Windows Media Encoder Lossless FFV1 Huffyuv Lagarith MSU Lossless YULS
See also: compression methods and compression formats

v t e Graphics file formats
Raster	ANI ANIM APNG ART AVIF BMP BPG BSAVE CAL CIN CPC CPT DDS DPX ECW EXR FITS FLIC FLIF FPX GIF HDRi HEVC ICER ICNS ICO / CUR ICS ILBM JBIG JBIG2 JNG JPEG JPEG-LS JPEG 2000 JPEG XL JPEG XR JPEG XS JPEG XT JPEG-HDR KRA MNG MIFF NRRD ORA PAM PBM / PGM / PPM / PNM PCX PGF PICtor PNG PSD / PSB PSP QOI QTVR RAS RGBE Logluv TIFF SGI TGA TIFF TIFF/EP TIFF/IT UFO / UFP WBMP WebP XBM XCF XPM XWD
Raw	CIFF DNG
Vector	AI CDR CGM DXF EMF EMF+ Gerber HVIF IGES PGML SVG VML WMF Xar
Compound	CDF DjVu EPS MODCA PDF PICT PS SWF XAML
Metadata	Exchangeable image file format (Exif) International Press Telecommunications Council § Photo metadata Extensible Metadata Platform (XMP) GIF § Metadata Steganography
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