Please see https://roundup.mplayerhq.hu/roundup/ffmpeg/issue348 for the full report. My platform is Ubuntu Linux 7.10 i386, running on a Pentium Core Duo 1.83 GHz notebook PC with 2GB RAM. These two videos were recorded using the latest SVN from 2008-2-12. The video x11grab-overmuxed-no_audio.avi was recorded using only x11grab, with no audio capture. Notice that it has a very aesthetically pleasing framerate. The video x11grab-overmuxed-audio.avi was recorded to capture both from x11grab and from /dev/dsp. Notice how jittery the framerate is. Also notice the bitrate does not increase nearly as quickly as the no_audio recording. I used a fixed video bitrate in this, but similar results are obtained using -qscale.