| 116 | | Be careful *not* to specify framerate with the "-r" parameter, like this {{{ffmpeg -f dshow -r 7.5 -i video=XXX}}}. This actually specifies that the devices incoming PTS timestamps be *ignored* and replaced as if the device were running at 7.5 fps [so it runs at default fps, but its timestamps are treated as if 7.t fps]. This can cause the recording to appear to have "video slower than audio" or, under high cpu load (if video frames are dropped) it will cause the video to fall "behind" the audio [after playback of the recording is done, audio continues on--and gets highly out of sync, video appears to go into "fast forward" mode during high cpu scenes]. |
| 117 | | |
| 118 | | If you want say 10 fps, and you device only supports 7.5 and 15 fps, then run it at |
| | 116 | Be careful *not* to specify framerate with the "-r" parameter, like this {{{ffmpeg -f dshow -r 7.5 -i video=XXX}}}. This actually specifies that the devices incoming PTS timestamps be *ignored* and replaced as if the device were running at 7.5 fps [so it runs at default fps, but its timestamps are treated as if 7.5 fps]. This can cause the recording to appear to have "video slower than audio" or, under high cpu load (if video frames are dropped) it will cause the video to fall "behind" the audio [after playback of the recording is done, audio continues on--and gets highly out of sync, video appears to go into "fast forward" mode during high cpu scenes]. |
| | 117 | |
| | 118 | If you want say 10 fps, and you device only supports 7.5 and 15 fps, then run it at 15 fps then "downsample" to 10 fps. There are a few ways to do this--you could specify your output to be 10 fps, like this: {{{ffmpeg -f dshow -framerate 15 -i video=XXX -r 10 output.mp4}}} or insert a filter to do the same thing for you: {{{ffmpeg -f dshow -framerate 15 -vf fps=15 output.mp4}}}. |
