Hi all, I’ve noticed that the generic file segmenter and the HLS segmenter act differently when seeking:
ffmpeg -i /path/to/file.mkv -map 0:0 -codec:0 copy -bsf:0 h264_mp4toannexb -map 0:1 -codec:1 aac -strict:1 experimental -channel_layout:1 stereo -segment_format mpegts -f segment -flags -global_header -segment_time 10 -segment_start_number 0 -segment_time_delta 0.0625 -max_delay 5000000 -avoid_negative_ts disabled -map_metadata -1 media-%05d.ts -start_at_zero -copyts -vsync cfr file.mkv has a length of 1391.232000 seconds, reported by ffprobe. Using a segment_time of 10, we expect about 140 segments: 001-138 with 10 seconds length, 139 with 1 second length. When we do not seek, we will get 138 segments, which is approximately what we expected. But now the problem: If we want to start at segment 130 -> ffmpeg with -ss 1300 and -segment_start_number 130, we would expect ffmpeg generating about 10 segments: 130-138 with 10 seconds length and 139 with 1 second length ffmpeg -ss 1300 -noaccurate_seek -i /path/to/file.mkv -map 0:0 -codec:0 copy -bsf:0 h264_mp4toannexb -map 0:1 -codec:1 aac -strict:1 experimental -channel_layout:1 stereo -segment_format mpegts -f segment -flags -global_header -segment_time 10 -segment_start_number 130 -segment_time_delta 0.0625 -max_delay 5000000 -avoid_negative_ts disabled -map_metadata -1 media-%05d.ts -start_at_zero -copyts -vsync cfr But this command will create more than ~140 segments. In this example the last segment suddenly gets the number 185, which does absolutely not fit to the calculation. When using -f hls the segmenter acts as expected: ffmpeg -ss 1300 -noaccurate_seek -i /path/to/file.mkv -map 0:0 -codec:0 copy -bsf:0 h264_mp4toannexb -map 0:1 -codec:1 aac -strict:1 experimental -channel_layout:1 stereo -segment_format mpegts -f hls -hls_time 10 -start_number 130 -segment_time_delta 0.0625 -max_delay 5000000 -avoid_negative_ts disabled -map_metadata -1 -hls_segment_filename media-%05d.ts playlist.m3u8 -start_at_zero -copyts -vsync cfr We get 138 segments, exactly like without seeking. Is this behavior expected? Thanks for any help, Steffen Deusch _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user
