1.2.0 Alpha 1 / 24 September 2010; 7 years ago ( 2010-09-24) Written in (incl, ),, Website Theora is a. It is developed by the and distributed without licensing fees alongside their other free and open media projects, including the audio format and the container. The libtheora is the of the Theora video compression format being developed by the Xiph.Org Foundation. Theora is derived from the formerly codec, released into the. It is broadly comparable in design and bitrate efficiency to, early versions of, and while lacking some of the features present in some of these other codecs. It is comparable in open standards philosophy to the 's codec. Theora is named after, 's Controller on the television program.
Jan 20, 2018 This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to. Theora; Filename extension.ogv,.ogg: Internet media type: video/ogg. Bitrate and file size between a YouTube H.264 video and a transcoded Ogg video file are. Best way to convert your MP4 to OGV file in seconds. 100% free, secure and easy to use! Convertio — advanced online tool that solving any problems with any files. In the following table, you can find a list of programs that can open files with.ogv extension.This list is created by collecting extension information reported by users through the 'send report' option of FileTypesMan utility. Best way to convert your OGV to MP4 file in seconds. 100% free, secure and easy to use! Convertio — advanced online tool that solving any problems with any files.
In 2014, a bug requesting Theora support on Android was closed 'Won't Fix (Obsolete)'. Wikipedia stopped preferring Ogg Theora and now prefers. Contents • • • • • • • • • • • • • • • • • • • Technical details [ ] Theora is a, -based video compression scheme.
Like most common video codecs, Theora also uses, -based motion compensation and an 8-by-8 DCT block. Pixels are grouped into various structures, namely blocks, super blocks, and. Theora supports intra-coded frames and forward-predictive frames, but not which are found in and. Theora also does not support, or bit-depths larger than 8 bits per component. Theora video streams can be stored in any suitable, but they are most commonly found in the container with or audio streams.
This combination provides a completely open, royalty-free multimedia format. It can also be used with the container. The Theora video-compression format is essentially compatible with the VP3 video-compression format, consisting of a backward-compatible superset. Theora is a superset of VP3, and VP3 streams (with some minor syntactic modifications) can be converted into Theora streams without recompression (but not vice versa).
VP3 video compression can be decoded using Theora implementations, but Theora video compression usually cannot be decoded using old VP3 implementations. See also: Theora's predecessor On2 TrueMotion VP3 was originally a and patent-encumbered developed. VP3.1 was introduced in May 2000 and followed three months later by the VP3.2 release, which is the basis for Theora.
Move to free software [ ] In August 2001, On2 Technologies announced that they would be releasing an open source version of their VP3.2 video compression algorithm. In September 2001, On2 Technologies published the of the VP3.2 codec under the VP3.2 Public License 0.1, a custom open-source license. The license only granted the right to modify the source code if the resulting larger work continued to support playback of VP3.2 data. In March 2002, On2 responded to the public's reception by relicensing the VP3 codec under the. In June 2002, On2 donated VP3 to the Xiph.Org Foundation and offered it under the Ogg Vorbis -style license.
On2 also made an irrevocable, license grant for any patent claims it might have over the software and any derivatives, allowing anyone to use any VP3-derived codec for any purpose. In August 2002, On2 entered into an agreement with the Xiph.Org Foundation to make VP3 the basis of a new, free video codec, called Theora. On2 declared Theora to be VP3's successor. [ ] On 3 October 2002, On2 and Xiph announced the completion and availability of the initial alpha code release of libtheora, Theora's reference implementation.
There is no formal specification for VP3's beyond the VP3 source code published by On2 Technologies. In 2003, Mike Melanson created an incomplete description of the VP3 bitstream format and decoding process at a higher level than source code, with some help from On2 and Xiph.Org Foundation. The Theora specification adopted some portions of this VP3 description. Project is working on the successor to Theora. Theora I specification [ ]. Example of a Theora video used on, showing a biplane at an aerobatic display.
The Theora I bitstream format was in June 2004 after the libtheora 1.0alpha3 release. Videos encoded with any version of the libtheora since the alpha3 will be compatible with any future player. This is also true for videos encoded with any implementation of the Theora I specification since the format freeze.
The Theora I Specification was completely published in 2004. Any later changes in the specification are minor updates. The Theora reference implementation libtheora spent several years in and beta status. The first alpha version was released on 25 September 2002 and the first beta version was released on 22 September 2007.
The first stable release of libtheora was made in November 2008. Work then focused on improving the codec's performance in the 'Thusnelda' branch, which was released as version 1.1 in September 2009 as the second stable libtheora release. This release brought some technical improvements and new features, such as the new rate control module and the. The codename for the next version of libtheora is Ptalarbvorm.
Theora is well established as a video format in applications, and is the format used for 's video content. However, the proposed adoption of Theora as part of the baseline video support in HTML5. Performance [ ] Encoding performance [ ] Evaluations of the VP3 and early Theora encoders found that their subjective visual quality was inferior to that of contemporary video codecs. More recently however, Xiph developers have compared the 1.1 Theora encoder to 's H.264 and encoders, in response to concerns raised in 2009 about Theora's inferior performance by, a employee. They found the results from Theora to be nearly the same as YouTube's H.264 output, and much better than the H. Air Vpn here. 263+ output.
The performance characteristics of the Theora 1.0 reference implementation are dominated mostly by implementation problems inherited from the original VP3 code base. Work leading up to the 1.1 stable release was focused on improving on or eliminating these. A May 2009 review of this work shows a considerable improvement in quality, both subjectively and as measured by, just by improving the forward and quantisation matrices. A flaw in the version of used in the test initially led to incorrect reports of Theora PSNR surpassing that of.
Although not achieving this goal, the improvement in the measured PSNR and the perceived quality is considerable. In any case, the differences in quality, bitrate and file size between a YouTube H.264 video and a transcoded Ogg video file are negligible. Further work on adaptive quantization, as well as overall detailed subjective tuning of the codec, is still to come. Playback performance [ ] There is an code base for a hardware Theora decoder in development. It began as a 2006 project, and it has been developed on both the and processors.
However, there are currently no Theora decoder chips in production, and, and similar devices with limited computing power rely on such chips to provide efficient playback. But since decoding Theora is less CPU intensive than decoding H.264, the need for hardware-accelerated Theora decoding may be somewhat less. [ ] Playback [ ]. Main article: As originally recommended by, these browsers support Theora when embedded by the video element: • and later versions including (Fennec).
• as of version 18.104.22.168 including as of 14 July 2009. • browser • as of version 2.0. • 4.4.2 • as of version. It was also supported in experimental video builds. • uses WebKitGTK+ as its rendering engine.
As WebKitGTK+ uses to implement the HTML5 media player, and all the formats GStreamer supports (including Theora) are available in browser. • is another example of a browser that supports Theora by using WebKitGTK+. Browser plugins [ ] • plugin via OggPlay •, a based •, a PHP wrapper for Cortado • Mv Embed HTML 5 video tag wrapper for numerous plugin types. • browser plugin for IE or Firefox Supporting media frameworks [ ] • with use of • supported via Theora or FFmpeg module, supports e.g. And • • (including but not limited to Safari) with use of • Highgate media suite is going to bring an Open Source Theora/Vorbis implementation in. It will enable installation-free support for HTML5 streaming video.