#3192: Dropped Frames With Overlay Filter -------------------------------------+------------------------------------- Reporter: ian_m | Owner: Type: defect | Status: new Priority: normal | Component: Version: git-master | undetermined Keywords: x11grab | Resolution: Blocking: | Blocked By: Analyzed by developer: 0 | Reproduced by developer: 0 -------------------------------------+------------------------------------- Comment (by jnvsor): I can confirm it occurs when both streams are passed through filter_complex, even if they are null filters that shouldn't effect performance at all. Low fps: {{{ ffmpeg -f x11grab -framerate 30 -s hd1080 -i :0.0 -f v4l2 -framerate 30 -i /dev/video0 -filter_complex '[0]null[cap];[1]null[webcam]' -map '[cap]' -map '[webcam]' -c:v libx264 -pix_fmt yuv444p -preset ultrafast -qp 0 -threads 2 -y out.avi }}} Remove either of the null filters and it will work at full framerate: {{{ - '[0]null[cap];[1]null[webcam]' - -map '[cap]' + '[1]null[webcam]' + -map 0 OR + '[0]null[cap]' + -map 1 }}} Add the v4l2 input first and it will work at full framerate: {{{ - -f x11grab -framerate 30 -s hd1080 -i :0.0 -f v4l2 -framerate 30 -i /dev/video0 + -f v4l2 -framerate 30 -i /dev/video0 -f x11grab -framerate 30 -s hd1080 -i :0.0 }}} It only occurs if that filter output is actually used, piping one to a nullsink also makes it work at full framerate: {{{ - '[0]null[cap];[1]null[webcam]' - -map '[cap]' + '[0]null[cap];[cap]nullsink;[1]null[webcam]' + -map 0 }}} -- Ticket URL: <https://trac.ffmpeg.org/ticket/3192#comment:11> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker