Multiview video coding
Multiview Video Coding ( MVC ) is a supplement to the video compression standard H.264 / MPEG-4 AVC for stereoscopic applications.
description
After those already in 2005 patented developments, stereoscopic video with MPEG-2 to realize encodings, was developed by the Moving Picture Experts Group which and Joint Video Team co-developed the multiview video coding standard to also signals from multiple simultaneously recorded To be able to save video cameras in a codec . In July 2008, the Moving Picture Experts Group officially approved the addition of the Advanced Video Coding (AVC) standard to multiview video coding.
Applications
Applications are in particular 3D television and the stereoscopic viewing of feature films and cartoons . The standard can also be used for applications of virtual reality , such as so-called Free Viewpoint Video (FVV) or Free Viewpoint Television (FTV), in which the viewer can determine his position and the viewing direction himself.
reproduction
The multiview video coding is independent of the playback method , so it can be played back with digital screens or projectors , for example . In order to view the images, shutter glasses are usually used, which alternately direct the images to the viewer's two eyes with the aid of electronically controllable liquid crystal layers. The alternating frequency is so high that the viewer does not notice it.
Alternatively, there are methods that generate the two stereoscopic images, for example with two projectors at the same time with perpendicular polarization directions , so that they can be viewed with polarization glasses that are equipped with two polarization filters aligned perpendicular to each other and therefore without electronic aids.
Corresponding developments are also in progress for mobile playback devices.
Furthermore, MVC can also be used for viewing three-dimensional images without tools. Here the impression of depth is created by autostereoscopy .
Open source software
Since 2011, the distribution of MVC-encoded video material has increased thanks to the Blu-ray Disc 3D and 3D camcorders from Sony .
Because of the patents on the MVC Codec, there was initially only commercial software that enabled the decoding or creation of MVC videos. Since the end of 2013 there has been a command line program called FRIM, written by a software developer called "videohelp3d". This allows MVC video to be converted to a different format and to clips for the left and right eyes, respectively.
As popular as open source H.264 and HEVC (H.265) decoders are and appear in the FFmpeg and Libav libraries, they simply ignore the additional information for the second (right-eyed) view and set it for stereoscopic views are not displayed. In most cases, a possible expansion to MVC was not sufficiently taken into account in the software design phase for the core functionality of H.264 and HEVC decoders. This entails subsequent complex changes to the program code ( refactoring ) and major changes to the existing software architecture. Activities such as disentangling and rearranging existing source code must be carried out as well as the splitting of various functions in the existing decoder source code into smaller units in order to be able to add software extensions such as MVC support more easily.
As part of research work, existing decoders were expanded to include MVC support, but their results have not yet been incorporated into the main development branch for official releases of FFmpeg or Libav .
With the release of version 0.98 of the DirectShow Media Splitter and Decoders Collection LAV Filters on March 8, 2016 by the author "Nevcairiel" - who is also working on the Media Player Classic - Home Cinema (MPC-HC) - the situation improved. Because this version supports the demultiplexing and decoding of H.264 MVC 3D. With the help of this version and FRIM it is possible to write an AviSynth script which converts an H.264 MVC 3D video clip into a side-by-side view when it is opened. This can then be opened by the free 3D video player Bino and then displayed as, for example, a red-cyan anaglyph 3D video.
The use of the AviSynth - plug-in (FRIMSource) is described on the "videohelp3d" homepage. LAV Filters can be used to use the audio from the original MVC video clip. Its developer confirmed its intention to provide a direct conversion of an MVC video clip (i.e. without the detour via AviSynth) into a side-by-side view in a future release.
Individual evidence
- ↑ TD Vision, Method and System for Digital Coding 3D Stereoscopic Video Images ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ^ Mitsubishi Electric Research Laboratories - Multiview Video Coding project
- ^ Technologies - Introduction to 3D Video
- ↑ NOKIA - Mobile 3D Video ( Memento of the original from May 30, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ http://www.videohelp.com/software/FRIM Videohelp download page. Accessed March 30, 2016
- ↑ http://forum.doom9.org/showthread.php?t=169651 developers page of "videohelp3d". Accessed March 30, 2016
- ↑ blogs.gentoo.org/lu_zero/2014/04/04/the-road-to-mvc/ The road to MVC
- ↑ http://www.nt.uni-saarland.de/fileadmin/file_uploads/theses/master/Optimized_implementation_of_a_MVC_decoder.pdf Jochen Britz - Optimized implementation of an MVC decoder - Master's Thesis in Computer and Communication Technology
- ↑ https://github.com/Britz/FFmpeg Britz - In terms of my master thesis, I work on a H.264 MVC implementation in libvacodec based on H.264 Annex H.
- ↑ https://github.com/Nevcairiel/LAVFilters GitHub repository of the LAV Filters project.Retrieved March 30, 2016
- ↑ http://bino3d.org/index.html Home page of Bino - a free 3D video player.Retrieved March 30, 2016
- ↑ http://forum.doom9.org/showthread.php?t=156191&page=1029 Developer homepage of "Nevcairiel" (at the bottom of the page). Retrieved March 30, 2016
