AVPro has many issues, ones I've noticed but certainly not an exhaustive list are:
  • Relies on platform-native APIs, meaning that the only reliable format in my testing, without having every user install codecs onto their device, is H.264 with AAC audio in a .mp4 or .ts container.
- Newer codecs like AV1 or VP9 are higher efficiency, which would save bandwidth for users and hosters, and platforms like YouTube are increasingly serving H264 less and less.
- Newer codecs would also allow content-focused worlds or live events to serve higher resolution/bitrate without sacrificing file-size/bandwidth
  • Inconsistencies with 5.1 or 7.1 audio.
  • VRChat's implementation lacks support for multi-track audio, video, or subtitles
- Multi-language audio within one file instead of multiple files would be nice.
- Relying on individual worlds to implement their own subtitle parsing and display isn't ideal. Subtitles are crucial for those who are hard of hearing, to watch content in other languages, or to watch content with quiet dialogue.
- (However, this could also be patched by exposing the AVPro audioTracks & subtitles in Udon)
  • Lacks support for LL-HLS, or WebRTC streams
- Newer livestream formats than the commonly used RTSP are more resilient to network interruption and would allow reliable playback with lower latency from more sources, like Twitch.
- WebRTC isn't as important but would allow for real-time interaction similar to how Discord screenshares allow for it.
Unity Video is also not a suitable replacement, due to
  • Cross-platform support of only H264 and VP8, in mp4/webm.
  • No HLS/DASH support
  • No livestream support
A new video-player backend could have large improvements for the VRChat playerbase.
Some options could be
Obviously these options would likely need to have patented codecs like HEVC removed to avoid legal issues, and would be a noticeable amount of dev-time, but I think it would be a hugely positive change.
Related: