On Fri, Oct 1, 2021 at 10:11 AM Bo Berglund <bo.bergl...@gmail.com> wrote:
> On Thu, 30 Sep 2021 14:35:27 +0200, Bo Berglund <bo.bergl...@gmail.com> > wrote: > > >I searched similar questions and found this regarding blackdetect filter > on > >stackoverflow: > > > https://stackoverflow.com/questions/18722747/can-you-put-the-result-of-a-blackdetect-filter-in-a-textfile-using-ffmpeg/32757533#32757533 > > > >It uses ffprobe and I tested it on one of my 64 minute videos and it could > >detect a number of black sections with start/end pairs: > > > >ffprobe -f lavfi -i "movie=myvideo.mp4,blackdetect[out0]" -show_entries > tags=lavfi.black_start,lavfi.black_end -of default=nw=1 -v quiet > > > >But in this case there were a number of false detections as well (black > sections > >within a commercial block) and each output was duplicated tike this: > > > >TAG:lavfi.black_start=55.533 > >TAG:lavfi.black_start=55.533 > >TAG:lavfi.black_end=57.833 > >TAG:lavfi.black_end=57.833 > >TAG:lavfi.black_start=778.467 > >TAG:lavfi.black_start=778.467 > >TAG:lavfi.black_end=779.067 > >TAG:lavfi.black_end=779.067 > >TAG:lavfi.black_start=839.033 > >TAG:lavfi.black_start=839.033 > >TAG:lavfi.black_end=839.067 > >TAG:lavfi.black_end=839.067 > > I have realized from comments here that the logo detection scheme is not > really > workable, so I am back to using this blackdetect method. > > One thing tah bugs me is that the command shown above duplicates the output > value on two lines, how can I make ffprobe output only one line for each > detection? > It would be easier to process in a script if the output was like this > instead: > > TAG:lavfi.black_start=55.533 > TAG:lavfi.black_end=57.833 > TAG:lavfi.black_start=778.467 > TAG:lavfi.black_end=779.067 > TAG:lavfi.black_start=839.033 > TAG:lavfi.black_end=839.067 > > Then a start is followed by an end and so on and the time between the > start and > end shows if a commercial insertion is found (short time between start and > end) > or if there is a deliberate long black section (which I would anyway want > to > exclude). > > So: > - How can i modify the ffprobe command such that it outputs just one line > for > every start or end point? I am not clever enough to figure out how ffprobe > actually works... > > - I notice a detection that lasts only 34 ms, could such be valid at all? > It > seems like a single video frame... > 1000/34 ~= 29 > > > -- > Bo Berglund > Developer in Sweden > > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".