For the Ruffle project developing the Adobe Flash Player emulator, prepared initial support for video playback and decoder implementation for video compression H.263 , which allows you to play video streams embedded in swf files (embedded bitstreams, so far without support for the flv player). The problem is that due to concerns about patent claims, the code may remain at the pull request stage for a very long time and will not be accepted into the main codebase.
Developers do not have the resources to understand which patents have already expired and which are still valid. The H.263 standard was adopted in 1995 and, according to preliminary data , the action of the latter is related to H.263 patent expires in 2023. At the same time, there has long been a free H.263 decoder supplied by the FFmpeg project, which entrusted the litigation with patents to third parties, making it possible to legally use H.263 in countries that do not accept software patents. The position of the ffmpeg project is that it does not try to analyze the intersection with patents, since there are so many patents that need to be checked, and the ITU and MPEG standards do not disclose the affected patents, only indicating that they are.