On 05/20/2011 02:35 PM, Peder Hedlund wrote: > Quoting Luka Prin?i? // Nova deViator <nova@xxxxxxxxxxx>: > >> >> hi, >> >> i have been doing videostreaming now number of times and somehow i >> always run into the same peculiar problem. >> >> whenever there is more action on camera, especially zoomins and a lot >> of audio (like bass and distorted vocals for example), the stream starts >> to continously skip chunks of video stream of about 0.5-1 second, >> every 0.5-1 second. > > The obvious guess would be that your CPU is too slow and can't keep up > with recoding the video stream. > The other guess is that the camera and/or the interface can't push that > amount of data in real time to the PC. Hi Luka, The problem is likely the former (the DV input is a bitstream with constant bps and usually no problem): Panning and zooming puts addidtional some strain on the encoder (motion compensation calc) and also produces bandwidth spikes. AT LAC, we were able to kick out some remote-participants with quick camera panning due to bandwith spikes so we tried to avoid those :) BTW, we were able to max-out CPU a 2.8GHz quad-core with two ffmpeg2theora instances. You can check if decreasing the quality (`-v 3`) helps and give `--speedlevel 2` a try: it uses less CPU, for increased output bandwidth. Down-scaling the video decreases CPU usage of the encoder, but requires a few CPU cycles to perform the scaling, in particular if scaling to non multiples of 16: try `-x 384 -y 288 -aspect 4:3` instead of ` -x 393 -y 288` (it /should/ not make a difference since Theora requires the geometry to be multiples of 8 (or 16?), but ffmpeg2theora may just be scaling/cropping/expanding twice?!). HTH, robin _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
