This feature is configured as explained here.
We support almost any container depending on how you built FFmpeg and which codecs are enabled. Right now we recommend only .avi and .mp4 as they are fully tested. .mkv and .webm will also work but not fully tested yet. The audio and video mixing is done using libavformat from FFmpeg.
- .avi (recommended) requires FFmpeg with MPEG4 video codec and AC3 audio codec
- .mp4 requires FFmpeg with H.264 (libx264 thirdparty library) video codec and AAC audio codec. There is a built-in experimental AAC codec in FFmpeg but the code is intentionally designed to not accept such codec because of random crashes. For AAC audio codec, you’ll need to build FFmpeg with libfaac or any other third-party AAC library. Please note that all AAC libraries are not free.
- .avi is recommended instead of .mp4 for the simple reason that the first one consume less CPU. The output file will have the bridge identifier as name and container type as extension, e.g. +336000000.avi. The file is locked and invalid until the last user quit the bridge.
We highly recommend using VLC to play the output files.