VP8

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VP8
Vp8-logo-for-mediawiki.svg
File extension : no
Developed by: On2 ( Google )
Initial release: September 13, 2008
Type: lossy video
Contained in: WebM , Matroska
Extended by: VP7
Expanded to: VP9
Standard (s) : RFC 6386


VP8 is a royalty-free format for lossy compressed video data . It builds on the TrueMotion line of development , a range of video formats developed and sold by On2 Technologies .

Together with the Vorbis audio format and a part of Matroska as a container format , VP8 is the first version of the WebM format recommended by Google for Internet video . The graphic format WebP is based on the intra-picture coding of VP8 .

According to Google, VP8 is mainly used in connection with WebRTC and as a format for animations, as a replacement for the Graphics Interchange Format (GIF).

VP8 is supported in Opera , Firefox , Chrome and Chromium web browsers . Internet Explorer officially supports VP8 with a codec that must be installed separately.

features

VP8 only supports full screen video signals with 4: 2: 0 color subsampling and 8 bits per sample . The VP8 implementation of On2 supports multi-core processors with up to 64 cores simultaneously in the first published version . At least with the implementation available (August 2011), VP8 is comparatively poorly adapted to high resolutions ( HD ). According to On2 Technologies, double the decoding speed is possible compared to VP7 with the same quality. According to x264 developer Jason Garrett-Glaser , the VP8 decoder - in the originally published open source version by Google - is slower than the H.264 / AVC decoder from the FFmpeg project. The only three reference images to be kept allow a comparatively memory-saving decoder implementation. The format also offers a pure intra mode, i.e. with freely accessible, independently coded single images without temporal prediction and mutual dependencies; for example as an intermediate format for video editing or the like.

Quality comparison to H.264 / AVC

According to On2, VP8 is competitive with H.264 / AVC . On2 stated that VP8 was comparatively dramatically superior in quality. A comparison video published by On2 Technologies is intended to demonstrate the improvements over (an implementation of the standard) H.264 / AVC. In contrast, an x264 developer compared VP8 with the quality of H.264 / AVC Constrained Baseline. In the first independent tests, VP8 and H.264 / AVC were found to be equivalent in the lowest profile “Baseline”, but these results were questioned in other articles. In the first published test using an Objective Metric ( SSIM ), VP8 could n't beat Xvid - a codec that implements the older MPEG-4 ASP standard - for some sample videos at high bit rates (at low bit rates, VP8 is always clearly superior ), and it fared worse than x264 for all sample videos. Only for one video could it achieve a quality similar, albeit inferior, to x264 - at a significantly slower speed. VP8 only lists this test in an appendix because the current version is too slow to be able to come close to the speed criteria specified for a fair comparison. In 2010, a further quality test using an algorithmic assessment based on the peak signal-to-noise ratio (PSNR) determined a “slightly” lower (1-4 dB) quality. A quality test published in August 2011 with subjective ratings by human test persons showed largely lower ratings for VP8 videos of the same bit rate compared to H.264 (JM and x264), but in summary it confirmed that the quality was competitive.

Patent situation

There are various views on freedom from patents - including doubts about the unencumbered nature of the issue, which even include the statement that the important techniques for video compression are covered by patents in such a way that all video formats are affected. Even with the predecessor Theora, there were fears about so-called submarine patents , which prevented some large companies from using them. In 2010, MPEG LA tried to put together a patent pool that was supposed to bundle claims against Theora and other free formats. There are also different views from the free software scene. The x264 developer Jason Garrett-Glaser came to his analysis of the process to the conclusion that having too many similarities to H.264 / AVC, to be not affected by the same claims. Christopher Montgomery (“Monty”, developer of Vorbis and Theora), on the other hand, considers the patent threats to be insubstantial from experience.

An employee of the Joint Technical Committee 1 of the ISO and the IEC comes to the conclusion in his analysis that On2 has made great efforts not to infringe any patents, but he also points out the difficulties with a modern video codec no infringements to commit. In addition, given the current legal situation in the United States , he believes it is unlikely that the public will ever know exactly what the company's internal investigations into the patent situation have looked like.

Apart from the difficult patent situation, VP8's original software license was not compatible with the requirements of the Open Source Initiative . Google removed the controversial paragraph from the license file on June 4, 2010.

On March 7, 2013, Google reached a funded agreement with MPEG LA to avert possible patent claims and the formation of a VP8 patent pool. This gives Google the right to distribute both VP8 and its successor VP9 in an open-source manner and free of charge.

technology

VP8 is a classic block-based transformation process. It has a lot in common with H.264 / AVC, for example some prediction modes. At the time of the first presentation of the VP8, according to On2, the in-loop filter and the golden frames were among the novelties compared to their predecessors. The first definition of such a filter was found in the H.263 standard , golden frames were already used in VP5 and VP7.

The basic frequency transformations are the discrete cosine transformation (DCT) with 4 × 4 blocks and the Hadamard transformation (WHT). A maximum of three other images can be referenced from a single image for temporal prediction: the last golden frame (possible intra-image), alternate reference image and the immediately preceding image. So-called alternate reference images (altref) can be used as pure reference images by deactivating their display. They can then be filled with any useful picture data by the encoder, also from future pictures, and thus fulfill the function of the B-pictures of the MPEG formats. Similar macroblocks of a single image can be assigned to one of up to four (also spatially unrelated) segments and then share parameters such as the reference image used, quantization step size and filter settings. VP8 offers two types of filters integrated into the codec loop (in-loop filtering) against block artifacts with adjustable strength. Many coding tools use probabilities that are continuously calculated from the current context on the basis of key frames or, optionally, golden frames. Macroblocks can comprise 4 × 4, 8 × 8 or 16 × 16 pixels. Motion vectors have a precision of one eighth of a pixel.

libvpx

The reference implementation of a VP8 codec can be found (in addition to VP9) in the libvpx program library, which was published as free software under the terms of a BSD license . The command line tools vpxencand vpxdec. There is one mode each for coding in a single pass and in two passes , whereby the single pass mode is considered broken and does not offer any useful control over the target bit rate. A detailed format analysis in August 2011 confirmed that the reference coder had poorly exploited the possibilities of the alternate reference images, and believes that with a correspondingly improved coder, an efficiency that is over 10 percent higher is possible. Further criticism concerned the quality of the bit rate control and the use of the image segmentation.

history

In September 2008, On2 Technologies released VP8 as the successor to their previous editions of the TrueMotion video format series such as VP6 and most recently VP7 . It should improve compression while reducing complexity. VP8 was originally developed as a proprietary, royalty-free technology and was disclosed after it was acquired by Google Inc.

Since Google's efforts to take over the manufacturer On2 became known, there have been expectations that VP8 should be released after the takeover. After months later on February 19, 2010 the takeover was sealed for 134 million US dollars, there was intensified speculation about the release. As a result of the takeover, the Free Software Foundation (FSF) asked Google in an open letter on April 30th to release the video technology and spoke of an opportunity to reduce the dependence on patented video formats such as H.264 and Adobe's proprietary Flash technology on the Internet to push back. With such a step, Google gave new impetus to the dispute over the standard format for web video with HTML5 with its popular (world's largest) video portal YouTube . At its developer conference Google I / O on May 19, 2010, Google released the reference codec of the format as Free Software in the source code for (patent) free use for everyone under the modified BSD license and at the same time the Matroska-based WebM container format presented for use on the Internet, in which Vorbis is used for audio compression in addition to VP8.

The release meant a great step forward in the field of patent-free video compression software, where VP8 can replace the qualitatively significantly inferior Theora alongside the Dirac , which is less suitable for real-time applications . The manufacturers of the majority of popular web browsers ( Internet Explorer , Firefox , Opera , Chrome ) announced that they would support the format in connection with HTML5 in the next (main) version and, in some cases, simultaneously publish developer versions with built-in support.

As of June 23, 2010, FFmpeg includes a native VP8 decoder. After a month of optimization, this implementation requires between 20% and 40% fewer resources to decode a VP8 video than Google's decoder.

Skype introduced in version 5 VP8 for video compression during telephone calls.

Google began to develop the successor format VP9 under the project name VP-Next . It is being discussed by the IETF as a proposal for a basis for a future Internet standard. At the end of 2012, support for VP9 was added to Chromium .

literature

  • Daniel Wolf: WebM / VP8 . Ed .: RWTH Aachen. Aachen August 31, 2012 ( tcs.rwth-aachen.de [PDF]).
  • Sean A. Cassidy: An Analysis of VP8, a new video codec for the web . Ed .: Rochester Institute of Technology. Rochester, New York November 2011 (English, scholarworks.rit.edu ).
  • Christian Feller, Juergen Wuenschmann, Thorsten Roll, Albrecht Rothermel (Ulm University): The VP8 Video Codec. Overview and Comparison to H.264 / AVC . In: IEEE (Ed.): IEEE International Conference on Consumer Electronics . ICCE-Berlin September 2011, p. 57–61 , doi : 10.1109 / ICCE-Berlin.2011.6031852 (English, moscow.sci-hub.bz [PDF]).

Web links

Individual evidence

  1. ↑ Alex Converse (Google), September 19, 2015: New video compression techniques under consideration for VP10 - Presentation at the VideoLAN Dev Days 2015 in Paris
  2. ↑ Nokia lines up patents against VP8 video codec. . Archived from the original on May 28, 2013. Retrieved March 25, 2013.
  3. ↑ Dean Hachamovitch (Microsoft) on March 16, 2011 on IEBlog: HTML5 Video Update — WebM for IE9
  4. ↑ a b Jason Garrett-Glaser (x264), May 19, 2010: The first in-depth technical analysis of VP8 ( Memento of the original from April 11, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (English), Analysis by x264 developer Jason Garrett-Glaser with comparison of VP8 and H.264 / AVC @1@ 2Template: Webachiv / IABot / x264dev.multimedia.cx
  5. ↑ Volker Zota (heise.de), September 11, 2008: TrueMotion VP8 video codec competes against H.264
  6. ↑ Comparison video ( Memento from August 6, 2009 in the Internet Archive )
  7. ^ Jan Ozer (Information Today, Inc.), May 20, 2010: First Look: H.264 and VP8 Compared . This article compares Google's VP8 encoder to Sorenson Squish, not a modern H.264 / AVC encoder like x264
  8. ↑ quAVlive ( Memento of the original from June 20, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (English) @1@ 2Template: Webachiv / IABot / www.quavlive.com
  9. ↑ Florian Kalenda, Stephen Shankland (ZDnet), June 2, 2010: Critics doubt the quality of Google's VP8 video codec
  10. ↑ MSU Graphics & Media Lab, June 16, 2010: MPEG-4 AVC / H.264 Video Codecs Comparison 2010, Appendix 8: VP8 encoder comparison with x264 and XviD
  11. ↑ Patrick Seeling, Frank HP Fitzek, Gergö Ertli, Akshay Pulipaka, Martin Reisslein: Video Network Traffic and Quality Comparison of VP8 and H.264 SVC . In: Proceedings of the 3rd workshop on Mobile video delivery (MoViD) . Association for Computing Machinery, New York 2010, p. 33–38 , doi : 10.1145 / 1878022.1878031 (English, s3.amazonaws.com [PDF]).
  12. ↑ Francesca De Simone, Lutz Goldmann, Jong-Seok Lee, Touradj Ebrahimi ( EPFL ): Performance analysis of VP8 image and video compression based on subjective evaluations . In: SPIE Optics and Photonics (Ed.): Applications of Digital Image Processing XXXIV . tape 8135 . San Diego, California August 2011, doi : 10.1117 / 12.896313 (English, infoscience.epfl.ch [PDF]).
  13. ↑ Jörg Thoma (golem.de), May 21, 2010: MPEG LA wants to examine possible patent infringements
  14. ↑ Volker Zota (heise.de), May 3, 2010: Steve Jobs: Patent pool with claims against Ogg Theora and others
  15. ↑ Carlo Daffara's patent analysis
  16. ↑ Cade Metz (The Register), May 24, 2010: Google open codec 'not open,' says OSI man - Net video play faces 'serious questions'
  17. ↑ Harald Bögeholz (heise.de), June 6, 2010: WebM project improves its open source license
  18. ↑ Press release of March 7, 2013: Google and MPEG LA Announce Agreement Covering VP8 Video Format
  19. ↑ Brief description in the MultimediaWiki
  20. ↑ Loop Filter ( Memento from September 18, 2008 in the Internet Archive )
  21. ↑ Golden Frames ( Memento from October 22, 2008 in the Internet Archive )
  22. ↑ Description of VP5 in MultimediaWiki
  23. ↑ Description of VP7 ( Memento from March 23, 2010 in the Internet Archive )
  24. ↑ Yaowu Xu, May 27, 2010: Inside WebM Technology: The VP8 Alternate Reference Frame
  25. ^ Dan Grois, Detlev Marpe, Tung Nguyen, Ofer Hadar: Comparative assessment of H.265 / MPEG-HEVC, VP9, ​​and H.264 / MPEG-AVC encoders for low-delay video applications . In: Proceedings of SPIE - Applications of Digital Image Processing XXXVII . tape 9217 . San Diego, California 2014, doi : 10.1117 / 12.2073323 (English).
  26. ↑ Jan Ozer, June 2016: VP9 Finally Comes of Age, But Is it Right for Everyone?
  27. ↑ Volker Zota (heise.de), February 19, 2010: Google completes takeover of the codec specialist On2 Technologies
  28. ↑ Free Software Foundation (FSF), February 19, 2010: Open letter to Google: free VP8, and use it on YouTube (English) - Open letter to Google
  29. ↑ Jens Ihlenfeld (golem.de), May 19, 2010: WebM: VP8 is open source
  30. ↑ Volker Zota (heise.de), May 20, 2010: Microsoft is taking a two-track approach: IE9 supports Google's VP8 / WebM in addition to H.264
  31. ↑ Volker Zota (heise.de), May 19, 2010: Google I / O: “Open Web Media Project” should establish VP8 as the video standard for the web
  32. ↑ VP8 integrated in FFmpeg
  33. ↑ Jason Garrett-Glaser (x264), July 23, 2010: Announcing the world's fastest VP8 decoder: ffvp8 ( Memento of the original from April 14, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. - Report on optimizations to ffvp8 (English) @1@ 2Template: Webachiv / IABot / x264dev.multimedia.cx
  34. ↑ Jens Ihlenfeld (golem.de), August 4, 2011: Video telephony: Skype is switching to Google's VP8 codec
  35. ↑ BoF meeting of the Conference IETF85 in Atlanta, United States giving a presentation to VP-Next. Audio recording (MP3, ~ 60 MiB), presentation slides (PDF, ~ 233 kiB)
  36. ↑ Stephen Shankland (CBS Interactive Inc.), December 28, 2012: Google's new VP9 video technology reaches public view