Mark Huang <mmhmmh <at> gmail.com> writes: > *ffmpeg -rtbufsize 100M -probesize 32 -debug_ts -y -threads 4 -vsync vfr I don't think -vsync vfr is supposed to work with mp4 output. > -async 1 -f avfoundation -s 640x480 -r 30.000000 -video_device_index 0 Why are you using -async 1? Carl Eugen