(I don't know how to ensure this will thread properly with my previous message, but perhaps the subject line will suffice). I made some progress re: the strange pts... to recap, this capture command: ffmpeg -f alsa -ac 2 -i hw:CARD=Cx231xxAudio,DEV=0 -f v4l2 -i /dev/video2 -c:a copy -c:v rawvideo test.avi ...generates broken .avi files with stuttering audio and audio pts's that increase at a rate of 4x the nb_samples. Remuxing like this: ffmpeg -i test.avi -c:a copy -c:v copy test-remuxed.avi ...fixes the file. I have learned that if I specify the sample type and rate, the generated file works: ffmpeg -f alsa -ac 2 -i hw:CARD=Cx231xxAudio,DEV=0 -f v4l2 -i /dev/video2 -c:a pcm_s16le -ar 48000 -c:v rawvideo test.avi ...I am specifying s16le and 48kHz, even though those are the values ffmpeg has detected itself. Not sure if this is a bug, or PEBCAK? -c