[theora] Key frame bitrate

Andreas Engel andreas.engel at bravis.eu
Tue Feb 8 23:39:02 PST 2011


Hi,

I'm using Theora for live video chat. My problem is, at higher bitrates 
the bandwidth peaks caused by key frames are so high that most key 
frames get dropped in UDP traffic. The peaks are so strong that I still 
get many packet loss artifacts when sending with 1Mbit/s bitrate on a 
2Mbit/s connection. I measured delta frames to be around 12kbyte and key 
frames up to 100kbyte in 1280x720 video at 15fps even with lowest rate 
buffer settings.
I can send 2Mbit/s without errors when using heavy traffic shaping, but 
this causes clearly visible delay.
In pre-1.0 API there was a parameter to set the bitrate for key frames 
which would probably help a lot with this. Is there any chance key frame 
bitrate control finds its way back into Theora? Or any other workaround 
for this?

Thanks in advance
Andreas


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