Stefano Sabatini: > On date Saturday 2024-04-20 18:47:58 +0200, Andreas Rheinhardt wrote: >> Stefano Sabatini: > [...] >>>> 1. This does not match mkvextract behaviour. mkvextract does not force a >>>> 1ms timebase. >>> >>> From your past comment: >>>> The accuracy of the timestamps output by mkvextract is determined by the >>>> TimestampScale of the file in question; it is most often 1ms when the >>>> file has video. >>> >> >> "most often" != "force" > [...] > >> (I am not certain wrt MKVToolNix handling of fractional millisecond; old >> versions of mkvextract may really have simply rounded/truncated to >> milliseconds.) > > It doesn't, at least with version: > $ mkvextract --version > mkvextract v65.0.0 ('Too Much') 64-bit >
With old I actually meant really old. As old as this muxer. > So far, mkvextract seems to output DTSs as in the original > implementation - therefore no need to change implementation, but for > the "timecode" => "timestamp" issue. > What is the TimestampScale of said file? Given that we are dealing with a video stream it is highly likely to be 1ms, so that there will be no difference. The following is from a 44100Hz with 4608 samples per packet and a TimestampScale of 22674 (equivalent to a timebase of 22674/1000000000 s). $ mkvextract fl.mka timestamps_v2 0:fl.txt Progress: 100% $ head -n 7 fl.txt # timestamp format v2 0 104.489795 208.97959 313.469385 417.95918 522.448975 (The following is with the current implementation, but your suggested patch won't change anything for it.) $ ./ffmpeg -i fl.mka -map 0:a -c copy -f mkvtimestamp_v2 - 2>/dev/null | head -7 # timecode format v2 0 104 209 313 418 522 $ ./ffprobe -hide_banner fl.mka -of csv=nk=1:p=0 -select_streams a:0 -show_entries packet=pts 2>/dev/null | head -n 6 0 4608 9216 13824 18433 23041 $ ./ffprobe -hide_banner fl.mka -of csv=nk=1:p=0 -select_streams a:0 -show_entries packet=pts_time 2>/dev/null | head -n 6 0.000000 0.104482 0.208964 0.313445 0.417950 0.522432 (The slight differences here with mkvextract is due to lacing: mkvextract calculates the timestamps of the non-leading packets in a lace with the default duration and uses nanosecond precision for this.) > $ ./ffprobe -hide_banner slow.mkv -of csv=nk=1:p=0 -select_streams v:0 > -show_entries packet=pts | head -n 20 > [...] > 0 > 1201 > 1235 > 1268 > 1368 > 1301 > 1335 > 1401 > 1435 > 1535 > 1468 > 1502 > 1602 > 1568 > 1735 > 1668 > 1635 > 1702 > 1768 > 1869 > > $ ./ffprobe -hide_banner slow.mkv -of csv=nk=1:p=0 -select_streams v:0 > -show_entries packet=dts | head -n 20 > N/A > N/A > 0 > 1201 > 1235 > 1268 > 1301 > 1335 > 1368 > 1401 > 1435 > 1468 > 1502 > 1535 > 1568 > 1602 > 1635 > 1668 > 1702 > 1735 > > $ mkvextract slow.mkv timestamps_v2 0:slow.mkv.out > Progress: 100% > $ head -n 21 slow.mkv.out > # timestamp format v2 > 0 > 1201 > 1235 > 1268 > 1301 > 1335 > 1368 > 1401 > 1435 > 1468 > 1502 > 1535 > 1568 > 1602 > 1635 > 1668 > 1702 > 1735 > 1768 > 1802 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".