Thanks for hinting in the right direction. Indeed there was no key frame up to sec. 10,5 (amazed by this!) The fact that QuickTime player did *not* show the cut beginning increased my confusion. But further processing with ffmpeg (concat) proves that the frames are there. Increasing the seek has solved the issue..
-----Mensaje original----- De: "Cley Faye" <cleyf...@gmail.com> Enviado: 19/10/2016 19:43 Para: "FFmpeg user questions" <ffmpeg-user@ffmpeg.org> Asunto: Re: [FFmpeg-user] issue with concat and seek 2016-10-19 17:51 GMT+02:00 Moritz Barsnick <barsn...@gmx.net>: > No, ffmpeg should actually cut with "-ss". Hmm, I'm not sure. This wiki page (https://trac.ffmpeg.org/wiki/Seeking ) says: > Using -ss as input option together with -c:v copy might not be accurate since ffmpeg is forced to only use/split on i-frames. Though it will—if possible—adjust the start time of the stream to a negative value to compensate for that. Basically, if you specify "second 157" and there is no key frame until second 159, it will include two seconds of audio (with no video) at the start, then will start from the first key frame. So be careful when splitting and doing codec copy. To me, it sound like it might copy all the video, and set the stream to start at the specified time, if there is no keyframe between the start and the cutting point. If that's the case, then concat might not be honoring this starting time. _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://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 http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".