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Thread: Video Codecs Information
03-09-2012, 04:46 PM #1
Video Codecs Information
Huffyuv (or HuffYUV) is a lossless video codec created by Ben Rudiak-Gould which is meant to replace uncompressed YCbCr as a video capture format. Despite the "YUV" in the name, it does not compress the YUV color space, but YCbCr. "Lossless" means that the output from the decompressor is bit-for-bit identical with the original input to the compressor, given that no color space conversion takes place. Huffyuv's algorithm is similar to that of lossless JPEG, in that it predicts each sample and then Huffman-encodes the error.
Lagarith is an open source lossless video codec written by Ben Greenwood. It was designed and written with a few aims in mind:
Speed; while not as fast as Huffyuv, it still outperforms most other lossless video codecs when it comes to encoding times, although decoding speed may be slower. Recent versions also support parallelizing on multi-processor systems.
Color-space support; color-space conversions can cause rounding errors, introducing data loss, contrary to the ideal of lossless video compression. Lagarith attempts to avoid this problem by supporting YV12, YUY2, RGB, and RGBA colorspaces.
Keyframes; disallowing inter-prediction means that each frame can be separately decoded. This makes cutting, joining and seeking much easier.
MPEG-4 Part 2 Codecs
DivX is a brand name of products created by DivX, Inc. (formerly DivXNetworks, Inc.), including the DivX Codec which has become popular due to its ability to compress lengthy video segments into small sizes while maintaining relatively high visual quality.
There are two DivX codecs; the regular MPEG-4 Part 2 DivX codec and the H.264/MPEG-4 AVC DivX Plus HD codec. It is one of several codecs commonly associated with "ripping", whereby audio and video multimedia are transferred to a hard disk and transcoded.
Xvid (formerly "XviD") is a video codec library following the MPEG-4 standard, specifically MPEG-4 Part 2 Advanced Simple Profile (ASP). It uses ASP features such as b-frames, global and quarter pixel motion compensation, lumi masking, trellis quantization, and H.263, MPEG and custom quantization matrices.
Xvid is a primary competitor of the DivX Pro Codec (Xvid being DivX spelled backwards). In contrast with the DivX codec, which is proprietary software developed by DivX, Inc., Xvid is free software distributed under the terms of the GNU General Public License. This also means that unlike the DivX codec, which is only available for a limited number of platforms, Xvid can be used on all platforms and operating systems for which the source code can be compiled.
FFmpeg is a free software / open source project that produces libraries and programs for handling multimedia data and publishes them under the GNU Lesser General Public License or GNU General Public License (depending on which options are enabled). The most notable parts of FFmpeg are libavcodec, an audio/video codec library used by several other projects, libavformat, an audio/video container mux and demux library, and the ffmpeg command line program for transcoding multimedia files.
The project was started by Fabrice Bellard (using the pseudonym “Gerard Lantau”), and is now maintained by Michael Niedermayer. Many FFmpeg developers are also part of the MPlayer project, and FFmpeg is hosted at the MPlayer project server. The name of the project comes from the MPEG video standards group, together with "FF" for "fast forward". The logo uses a zigzag pattern that shows how MPEG video codecs handle entropy encoding.
FFmpeg is developed under GNU/Linux, but it can be compiled under most operating systems, including Apple Inc. Mac OS X, Microsoft Windows and AmigaOS. Most computing platforms and microprocessor instruction set architecture are also supported, like x86 (IA-32 and x86-64), PPC (PowerPC), ARM, DEC Alpha, SPARC, and MIPS architecture.
FFmpeg version 0.5 appeared after a long time without formal releases. Previously, FFmpeg developers recommended using the latest neutral build from their source code Subversion version control system as development attempts to maintain a stable trunk.
There are two video codecs and one video container invented in the FFmpeg project during its development. The two video codecs are the lossless "FFV1", and the lossless or lossy "Snow codec", which is still in a sporadic development, but its bitstream format hasn't been finalized yet, making it experimental for now (January 2010), and the multimedia container is "NUT" which is not being actively developed anymore.
3ivx is a video codec created by 3ivx Technologies, based in Sydney, Australia.
3ivx is a codec suite that allows the creation of MPEG-4 compliant data streams. It has been designed around a need for decreased processing power for use mainly in embedded systems. First versions was published in 2001. 3ivx provides plugins and filters that allow the MPEG-4 data stream to be wrapped by the Microsoft ASF and AVI transports, as well as Apple's QuickTime transport. It also allows the creation of elementary MP4 data streams and provides an audio codec for creation of AAC audio streams. It does not support H.264 video (MPEG-4 Part 10). Only MPEG-4 Part 2 video is supported.
H.264/MPEG-4 AVC Codecs
x264 is a free software library for encoding video streams into the H.264/MPEG-4 AVC format. It is released under the terms of the GNU General Public License.
x264 provides a command line interface as well as a library-level interface. The former is used by many graphical user interfaces, such as Staxrip and MeGUI. The latter is used by many other interfaces, such as Handbrake and FFmpeg.
H.264/MPEG-4 AVC is a standard for video compression. The final drafting work on the first version of the standard was completed in May 2003.
H.264/AVC is the latest block-oriented motion-compensation-based codec standard developed by the ITU-T Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG), and it was the product of a partnership effort known as the Joint Video Team (JVT). The ITU-T H.264 standard and the ISO/IEC MPEG-4 AVC standard (formally, ISO/IEC 14496-10 - MPEG-4 Part 10, Advanced Video Coding) are jointly maintained so that they have identical technical content. H.264 is used in such applications as Blu-ray Disc, videos from YouTube and the iTunes Store, DVB broadcast, direct-broadcast satellite television service, cable television services, and real-time videoconferencing.
The intent of the H.264/AVC project was to create a standard capable of providing good video quality at substantially lower bit rates than previous standards (e.g. half or less the bit rate of MPEG-2, H.263, or MPEG-4 Part 2), without increasing the complexity of design so much that it would be impractical or excessively expensive to implement. An additional goal was to provide enough flexibility to allow the standard to be applied to a wide variety of applications on a wide variety of networks and systems, including low and high bit rates, low and high resolution video, broadcast, DVD storage, RTP/IP packet networks, and ITU-T multimedia telephony systems.
The H.264 standard is a "family of standards", the members of which are the profiles described below. A specific decoder decodes at least one, but not necessarily all profiles. The decoder specification describes which of the profiles can be decoded.
The standardization of the first version of H.264/AVC was completed in May 2003. The JVT then developed extensions to the original standard that are known as the Fidelity Range Extensions (FRExt). These extensions enable higher quality video coding by supporting increased sample bit depth precision and higher-resolution color information, including sampling structures known as YUV 42 and YUV 44. Several other features are also included in the Fidelity Range Extensions project, such as adaptive switching between 4×4 and 8×8 integer transforms, encoder-specified perceptual-based quantization weighting matrices, efficient inter-picture lossless coding, and support of additional color spaces. The design work on the Fidelity Range Extensions was completed in July 2004, and the drafting work on them was completed in September 2004.
Nero Digital is a brand name applied to a suite of MPEG-4-compatible video and audio compression codecs developed by Nero AG of Germany and Ateme of France. The audio codecs are integrated into the Nero Digital Audio+ audio encoding tool for Microsoft Windows, and the audio & video codecs are integrated into Nero's Recode DVD ripping software.
QuickTime is an extensible proprietary multimedia framework developed by Apple, capable of handling various formats of digital video, 3D models, sound, text, animation, music, panoramic images, and interactivity. It is available for Mac OS classic (System 7 onwards), Mac OS X and Microsoft Windows operating systems. The latest version is QuickTime X (10.0) and is currently only available on Mac OS X v10.6.
QuickTime is integrated with Mac OS X, and it was an optional component at install for earlier versions of Mac OS. All Apple systems ship with QuickTime already installed. QuickTime for Windows systems is downloadable, either as a standalone installation or bundled with iTunes.
DivX Pro Codec: An H.264 decoder and encoder was added in version 7.
Windows Media Video (WMV) is a compressed video compression format for several proprietary codecs developed by Microsoft. The original video format, known as WMV, was originally designed for Internet streaming applications, as a competitor to RealVideo. The other formats, such as WMV Screen and WMV Image, cater for specialized content. Through standardization from the Society of Motion Picture and Television Engineers (SMPTE), WMV 9 has gained adoption for physical-delivery formats such as HD DVD and Blu-ray Disc.
A WMV file is in most circumstances encapsulated in the Advanced Systems Format (ASF) container format. The file extension .WMV typically describes ASF files that use Windows Media Video codecs. The audio codec used in conjunction with Windows Media Video is typically some version of Windows Media Audio, or in rarer cases, the deprecated Sipro ACELP.net audio codec. Microsoft recommends that ASF files containing non-Windows Media codecs use the generic .ASF file extension.
The ASF container can optionally support digital rights management using a combination of elliptic curve cryptography key exchange, DES block cipher, a custom block cipher, RC4 stream cipher and the SHA-1 hashing function.
Although WMV is generally packed into the ASF container format, it can also be put into the AVI or Matroska container format. The resulting files have the .AVI and .MKV file extensions, respectively. WMV can be stored in an AVI file when using the WMV 9 Video Compression Manager (VCM) codec implementation. Another common way to store WMV in an AVI file is to use the VirtualDub encoder.
Windows Media Video (WMV) is the most recognized video format within the WMV family. Usage of the term WMV often refers to the Microsoft Windows Media Video codec only. Its main competitors are MPEG-4 AVC, AVS, RealVideo, DivX, and Xvid. The first version of the codec, WMV 7, was introduced in 1999, and was built upon Microsoft's implementation of MPEG-4 Part 2. Continued proprietary development led to newer versions of the codec, but the bit stream syntax was not frozen until WMV 9. While all versions of WMV support variable bit rate, average bit rate, and constant bit rate, WMV 9 introduced several important features including native support for interlaced video, non-square pixels, and frame interpolation. WMV 9 also introduced a new profile titled Windows Media Video 9 Professional, which is activated automatically whenever the video resolution exceeds 300,000 pixels (e.g., 528x576, 640×480 or 768x432 and beyond) and the bitrate 1000 kbit/s. It is targeted towards high-definition video content, at resolutions such as 720p and 1080p.
The Simple and Main profile levels in WMV 9 are compliant with the same profile levels in the VC-1 specification. The Advanced Profile in VC-1 is implemented in a new WMV codec called Windows Media Video 9 Advanced Profile. It improves compressions efficiency for interlaced content and is made transport-independent, making it able to be encapsulated in an MPEG transport stream or RTP packet format. The codec is not compatible with previous WMV 9 codecs, however.
WMV is a mandatory video codec for PlaysForSure-certified online stores and devices, as well as Portable Media Center devices. The Microsoft Zune, Xbox 360, Windows Mobile-powered devices with Windows Media Player, as well as many uncertified devices, support the codec. WMV HD mandates the use of WMV 9 for its certification program, at quality levels specified by Microsoft. WMV used to be the only supported video codec for the Microsoft Silverlight platform, but H.264 codec is now also supported starting with version 3.
MS MPEG-4v3: A proprietary and not MPEG-4 compliant video codec created by Microsoft. Released as a part of Windows Media Tools 4. A hacked version of Microsoft's MPEG-4v3 codec became known as DivX ;-).
VC-1 is the informal name of the SMPTE 421M video codec standard. Initially developed as a proprietary video format by Microsoft before it was released as a formal SMPTE standard video format on April 3, 2006. It is today a supported wide spread standard for HD DVDs, Blu-ray Discs, Windows Media Video 9, and Microsoft's Silverlight framework.
VC-1 is an evolution of the conventional DCT-based video codec design also found in H.261, H.263, MPEG-1, MPEG-2, and MPEG-4 Part 2. It is widely characterized as an alternative to the latest ITU-T and MPEG video codec standard known as H.264/MPEG-4 AVC. VC-1 contains coding tools for interlaced video sequences as well as progressive encoding. The main goal of VC-1 development and standardization is to support the compression of interlaced content without first converting it to progressive, making it more attractive to broadcast and video industry professionals.
Although widely considered to be Microsoft’s product, there are actually fifteen companies in the VC-1 patent pool (as of August 17, 2006). As an SMPTE standard, VC-1 is open to implementation by anyone, although implementers are hypothetically required to pay licensing fees to the MPEG LA, LLC licensing body or directly to its members, who claim to hold essential patents on the format (since it is a non-exclusive licensing body).
Both HD DVD and Blu-ray Disc have adopted VC-1 as a video standard, meaning their video playback devices will be capable of decoding and playing video-content compressed using VC-1. Windows Vista partially supports HD DVD playback by including the VC-1 decoder and some related components needed for playback of VC-1 encoded HD DVD movies.
Microsoft has designated VC-1 as the Xbox 360 video game console’s official video codec, and game developers may use VC-1 for full motion video included with games. By means of an October 31, 2006 update, people can now play all formats of Windows Media Video on the Xbox 360 from a disc, USB storage device, or streaming from their PC via Windows Media Connect/Windows Media Player 11. This allows anyone to play VC-1 encoded files on the console.
This codec was also included in the PlayStation 3
The FFmpeg project includes a free VC-1 decoder.
VP6, VP6-E, VP6-S, VP7: Proprietary high definition video compression formats and codecs developed by On2 Technologies used in platforms such as Adobe Flash Player 8 and above, Adobe Flash Lite, Java FX and other mobile and desktop video platforms. Supports resolution up to 720p and 1080p.
libtheora: A reference implementation of the Theora video compression format developed by the Xiph.org Foundation, based upon On2 Technologies' VP3 codec, and christened by On2 as the successor in VP3's lineage. Theora is targeted at competing with MPEG-4 video and similar lower-bitrate video compression schemes.
Schrödinger and dirac-research: implementations of the Dirac compression format developed by BBC Research at the BBC. Dirac provides video compression from web video up to ultra HD and beyond.
DNxHD codec: a lossy high-definition video production codec developed by Avid Technology. It is an implementation of VC-3.
Sorenson 3: A video compression format and codec that is popularly used by Apple's QuickTime, basically the ancestor of H.264. Many of the QuickTime movie trailers found on the web use this compression format.
Sorenson Spark: A codec and compression format that was licensed to Macromedia for use in its Flash Video starting with Flash Player 6. It is considered as an incomplete implementation of the H.263 standard.
RealVideo: Developed by RealNetworks. A popular compression format and codec technology a few years ago, now fading in importance for a variety of reasons.
Cinepak: A very early codec used by Apple's QuickTime.
Indeo, an older video compression format and codec initially developed by Intel.