[FFmpeg-user] Save segmented and fragmented h264 to disk

Mark Umansky umansky at torcrobotics.com
Thu Oct 2 16:00:46 CEST 2014


I am currently recording video of the desktop using UScreenCapture set up as shown in http://nerdlogger.com/2011/11/03/stream-your-windows-desktop-using-ffmpeg/, that's all set up working fine. Running the ffmpeg static 64 bit build from 2014-09-28 (git-3edb9aa) in Windows 7 64bit

I get playable fragmented mp4 (played in VLC) saving correctly with the following command:

ffmpeg -f dshow -i video="UScreenCapture" -vcodec libx264 -r 25 -q 5 -preset ultrafast -movflags frag_keyframe  C:\Users\user\Desktop\video.mp4 -y

I'd like to segment files by time, so I get X minute chunks of video that are all individually playable as well as preserving fragmentation in case of power loss (this will be running on a portable computer).

When I run:

ffmpeg -f dshow -i video="UScreenCapture"  -codec copy -map 0 -f segment -vcodec libx264 -q 5 -r 25 -preset ultrafast -movflags frag_keyframe -segment_time 10 -reset_timestamps 1 C:\Users\user\Desktop\Video_%04d.mp4 -y

I cannot get the last file (the fragmented one) to play at all. (The segmented files before the last one are fine) The last file has data in it (filesize is non-zero) but VLC cannot open it. Ideally the fragmented file wouldn't require any additional processing later to turn it into a non-fragmented file that's playable.

Any help would be appreciated.


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