Carl Eugen, Thanks for taking the time to answer my questions.
On Sun, Nov 29, 2020 at 7:40 PM Carl Eugen Hoyos <[email protected]> wrote: > > Am So., 29. Nov. 2020 um 16:32 Uhr schrieb Mathieu Malaterre > <[email protected]>: > > > $ ffmpeg -y -i input.avi -c:v libx264 -b:v 1321894 -pass 1 -an -f null > > /dev/null && \ > > ffmpeg -y -i input.avi -c:v libx264 -b:v 1321894 -pass 2 -c:a aac -b:a > > 128k fixed.mp4 > > This cannot work (and this is not related to the fact that you are not > using a version of FFmpeg that we support here). > > In some cases - if you are lucky - there is a crash and no output file > is written, in other cases, a "broken" output file is written, broken in > the sense that two-pass encoding did not work the way it is supposed > to (more bitrate was given to frames that do not need it). > > Do not use -an on the first pass and add "-vsync cfr" to the first pass. > (Other workarounds are possible.) Confirmed. The above suggestion does fix the symptoms. Did you base your suggestion on: "Error while decoding stream #0:1: Invalid data found when processing input" ? > For future questions: Do not cut FFmpeg's console output, only > post ffprobe output if you see an issue with it. > > Not really related: > > Does it make sense to simply copy/paste the existing bit_rate to > > re-encode it ? > > No, to the best of my knowledge, it makes no sense whatsoever. > > Very generally you either want a specific output quality, in this > case specifying a bitrate and two-pass encoding make no > sense. > Or you have a particular size requirement for the output file, > then bitrate and two-pass encoding make sense. Are you saying that taking the original file size as size requirement is the whole issue ? If I follow the guide again and do the computation as described, the bitrate value is just very slightly different: >>> 690*8192./(3600+6*60+2) - 128 1298.673397274104 Assuming my mp3 audio did not have any particular problem, would there be an actual difference in between using -b:v 1298k vs -b:v 1321894 ? Thanks again, > Carl Eugen > _______________________________________________ > ffmpeg-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". -- Mathieu _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
