It would be nice to allow more than one b-frame (#800 / r12868) to be buffered in the video encoder rather than delaying the uncompressed video frames before encoding. (much more efficient use of space)
Difficulty here is that not all encoders will allow us to change the number of b-frames dynamically, and we may need to do this as the av-sync delay varies. (see #835 / #1164)
Note: x264 already does buffer more than one frame: #2064 / r21114 caps it at 4.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1261