Learning notes for codecs (10): OGG series

Source: Internet
Author: User

Ogg is a free and open standard container format, funded by xiph.org maintenance.

The OGG format is not limited by software patents and is designed to efficiently handle high-quality streaming and digital media.

Ogg means a file format that can be incorporated into a wide variety of free and open source codecs. Includes audio, video, text (like subtitles) and metadata processing.

Ogg Theora

Theora is a non-entitlement gold, open format lossy image compression technology. Developed by the Xiph.org Foundation, the foundation also developed the renowned sound coding technology Vorbis, as well as the multimedia container archive Ogg. Theora is derived from the On2 Technologies Company's proprietary VP3 encoder after open source. Theora's name comes from a TV show Max Headroom.

The Theora is a variable bit rate, DCT-based image compression format. As with most image encoding formats, Theora uses chroma sampling, block based motion compensation and 8x8 DCT blocks, as well as video compression image types and video compression image types, but does not support the use of the H + + and vc- 1 of Bi-predictive frames (b-frame). Theora also does not support interlaced scanning, variable frame rates, or bit-depths larger than 8 bits per component.

Theora's image stream can be stored in any container file format, most often used in conjunction with the sound coding Vorbis in the Ogg file format, such a way to provide a completely open, royalty-free multimedia files. In addition, Theora images can be stored in Matroska files.

Google's official blog says web video does not have a standard at the moment, and some sites use flash. However, this requires the user to have a Flash player, some using a Java player, but to decode the video and audio users in the JVM virtual machine requires a very high-profile machine, and so on.

The good news is that the new generation of the HTML 5 standard introduces video elements that Web developers can use to specify the appearance of the video in a standard way. The question now becomes which video format to use.

Google feels that the open standard format can be the bottom line for today's chaotic video format struggles.

The final benefit scheme does not require the most complex format. Or perhaps the most publicized, almost become the industry standard format, so they decided to choose to support the use of the extensive open source Ogg Theora format.

Theora is an open source derivative of the VP3 encoder of On2 Technologies, which Google acquired last year for its On2 company.

Source: http://tech.it168.com/a2010/0412/872/000000872493.shtml

In March 2002. ON2 will change the license to next week VP3 Open source code is LGPL. In June 2002, On2 VP3 as an open-source license for Xiph.org and under a similar BSD. ON2 also has a non-changing royalty-free statement, no matter what the person can use for whatever software, whatever derivative products and for whatever purpose. 2002 88 months, ON2 signed an agreement with Xiph.org, which will VP3 as a new, free video codec. Become Theora. On2 claimed that Theora was a successor to VP3. On October 3, 2002. On2 and Xiph announced the release of Theora's earliest alpha code.

The bitstream format was frozen in 2004 (version 1.0 ALPHA3), with a beta version number of several years, Theora the first stable version number (v1.0) released in November 2008.

Theora no matter what the version number of the video encoding after the format freezes are compatible with the future player. The current work focuses on bug fixes in the "Thusnelda" branch, which is now the beta version and will be released last as the Theora1.1 version number.

The Theora video compression format is basically compatible with the VP3 video compression format, including a post-first-compatible superset. Theora is a superset of the VP3 and VP3 streams (with a small amount of syntax revisions), and the VP3 stream can be changed to Theora stream without having to compress it again, but in turn it is set up.

VP3 video compression can be decoded by Theora. However, Theora video demos are often not able to decode with the old VP3.

Theora video format based on open source, and as the base of the video content selection of the encoding format. However, Theora lacks commercial support. And is trying to get distributors, especially network distributors to accept.

Mozilla uses this technology to provide HTML5 video on Firefox.

Apple and Microsoft's HTML5 video are all ready to be managed with MPEG LA.

Members of the group include Microsoft and Apple, as well as many technology companies.

The crux of the controversy lies in the problem of license, which is needed for license.

Mozilla issued the following statement: "We believe. HTML5 video in multi-party, open and no-entitlement codecs. Supported by the same type of licensing standards. is in the public interest. We would definitely consider using this technology if MPGA LA is willing to provide H. A according to the open network conditions defined by the Web Standard. The organization adheres to our position on Theora. ”

Hakon Wium Lie, chief technical officer of Opera, also provided the following statement: "To open up the network of growth and flourish." All media (including video) must be used without the need to pay the codec/decoder license fee. A browser manufacturer who really supports an open network must work hard to build a basic audio/video codec with no licensing fees. ”

Microsoft's Company blog wrote: "Whether the source can be obtained, and the difference between the intellectual property, is the use of the source code is extremely necessary." Right now, the intellectual property of H. Can be obtained through a defined and understood scheme of MPEG LA Management. Other codec/decoder rights are usually less clear. ”

Ogg Vorbis

  Ogg's audio encoding. Excellent quality, especially under low bit rate, multi-channel support. The maximum code rate can reach 500kbps, is a strong competitor of AAC.

"ogg" this term usually means Ogg Vorbis this audio file format, that is, the Vorbis encoded sound is included in the format of the Ogg container.

In the past,. ogg this extension was previously used in whatever Ogg supported format, but in the year 2007. The Xiph.org Foundation made a request for backwards compatibility considerations. The. ogg is reserved for use only in the Vorbis format. The Xiph.org Foundation decided to create some new extensions and media formats to describe different types of content. It's like just a sound effect. OGA, including or without the sound of the film (covering Theora) used by the. OGV and the. OGX used by the program.

Vorbis is an open source free software project leader who is the Xiph.org Foundation. The Digital audio format specification and software implementation (codec) produced by the project are lossy audio compression. Vorbi is most often used in conjunction with the Ogg container format and is therefore commonly referred to as the Ogg Vorbis format.

Vorbis is a continuation of the development of audio compression started in 1993 by Chris Montgomery. Intensive development began in September 1998. The Faith Fraunhofer Association the company announced that it will charge a license fee for the MP3 audio format. Vorbis's project started as part of the company, the Xiph.org Foundation's Ogg project (also known as the Oggsquish Multimedia project). Chris Montgomery started working on the project. and to assist more and more other developers. They continued intact source until the Vorbis file format was frozen May 2000 for 1.0 and a stable version number (1.0) of the reference software was published on July 19, 2002.

Ogg Speex

Ogg's voice coding, specifically for low bit rate speech coding.

Ogg FLAC

  OGG's lossless audio encoding.

ON2 VPX Series

  ON2 Company has developed a series of excellent video coding, the most used today is probably Nullsoft video, they use the VP3,VP5,VP6 video encoding.

VP3

has been released as open source. Now is the Ogg Theora project, of course, Theora quality is better than VP3.

VP4

ON2 company boasted the best video coding in the world, and later proved the quality is very general.

VP5

Still very magical, On2 did not put out, only in Nullsoft Video inside see his figure.

VP6

From the beginning, On2 this encoder to everyone to download. The quality is still good. Just recently it seems to be closed, there is only one decoder on the homepage. On2 TrueMotion VP6 is a proprietary lossy video codec format and video codec. It is a detailed embodiment of TrueMotion video codec, is a series of video codec developed by ON2, produced for Adobe Flash. Flash video and JavaFX media files.

VP7

ON2 the latest encoder, there is a lot of progress on VP6.

In January 2005, ON2 announced the introduction of a new codec VP7 with better compression ratios than VP6.

In 2005ian4 month, ON2 company licensed ON2 Video Encoder 9 contains VP6 and VP7) for Macromedia Flash.

In August 2005, Macromedia announced that they chose VP6 as the flagship codec for the new Flash Player8 video playback.

VP8

Google acquired On2 Technologies in 2009. and announced at the Google I/O conference on May 19, 2010 that VP8 is open source in the form of a BSD license.

。 VP8 is the second codec that announces open source after VP3 ON2 technologies. (The Xiph.org Foundation took over VP3 in 2002 and named it Theora, then Theora open source in the form of a BSD license). The biggest call for Google to VP8 Open source comes from the Free Software Foundation. March 12, 2010, the Free Software Foundation sent an open letter to Google, asking Google to gradually replace Adobe Flash and H. 5 on YouTube with source-VP8 and HTML.

May 19, 2010, WEBM started.

WEBM includes contributions from Mozilla, Opera, Google and more than 40 other publishers and computer hardware and software vendors, including AMD, NVIDIA, to aggressively advocate the use of VP8 in HTML5.

Internet Explorer 9 can also support VP8 after the appropriate codec is installed.

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Learning notes for codecs (10): OGG series

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