H.264 error resiliency

Tasks

• to prevent running out of the bitrate, H.264 frames must be as even as possible
• let decoder process even partially corrupted frames
  • test which decoders crash on scrambled data
  • zero buffer space where data are missing due to missing packets (maybe not needed but more safe)
• divide RTP packets according to H.264 NAL units (like it is already for RFC-compliant transmission)
• consider fetching the lavd not H.264 frames but NAL units/packets
• consider invalidating incomplete NAL units
• different transport (SRT/QUIC/UDT)

Testing

• testing data for all tests trud:/mnt/xfs/videa/New/Zeland/NZ-1080p-yuv-H.264-15M
• loss is emulated by https://wiki.linuxfoundation.org/networking/netem (works on egress)

Test Case 1, 2

First test without and second with Reed-Solomon forward error correction:

sudo tc qdisc replace dev lo root netem loss 5%
uv --playback NZ-1080p-yuv-H.264-15M -d gl:fs [-f rs:200:220]