On 10.10.23 22:26, Alper Kücük via ffmpeg-user wrote:[...]
recover_mp4.exe good.mp4 result.h264 result.wav
I'm not familiar with recover_mp4.exe
Please verify that your result.h264 really contains a flawless video
track of equal duration as the audio track result.wav
You can do this by trying to play the results audio and video with
ffplay, probing with ffprobe gives you the estimated duration of video
and audio
ffmpeg.exe -r 60000/1001 -i result.h264 -i result.wav -c:v copy -c:a
copy result.mov
As you describe your end result, your video track might contain too few
or even no video data. In this case your audio would get transcoded
completely, while the video output keeps playing the last frame of the
video track. This seems to be the default of ffmpeg. Encountered this
myself with shorter audio than video while post-editing a master.mp4. In
my usecase audio went out of sync, leaving tiny audio gaps at the ends
of all 10-second-clips.
At least for the Linux-version ffmpeg/ffplay/ffprobe doesn't require a
file extension for input files, since it probes the input-file anyway in
order to activate a compatible demuxer.
Your -r 60000/1001 results in about 60fps. Since you copy both video
and audio this might as well be ignored by ffmpeg.
To repair buggy videos I use two passes, one for video and for audio.
ffmpeg -an -i buggy.mp4 buggy-video.avi
ffmpeg -vn -i buggy.mp4 buggy-video.wav
Rumor has it, that both AVI and WAV are lossless formats. And this way
ffmpeg salvages all that is left from buggy.mp4
Now you can examine both video and audio separately with ffplay and ffprobe
As described above, different durations result in a desynchronized video
when using -c:copy for both video and audio
In this case you might want to stretch the shorter track to the duration
of the longer one. Or squeeze the longer one to hurry up.
For audio i recommend the rubberband filter, e.g. something like this:
-af rubberband=tempo=$TEMPO
For video I found the minterpolate filter the best choice for my needs.
Korn-Shellscript Snippet following:
MI_MODE="dup"
#MI_MODE="blend"
#MI_MODE="mci"
VSPEED="minterpolate=mi_mode=$MI_MODE:me_mode=bidir:mc_mode=aobmc:me=esa:scd=none:scd_threshold=5.0:vsbmc=1:search_param=32:fps=$FPS/$SPDSTART,setpts=1/$SPDSTART*PTS"
When $SPDSTART and $TEMPO are set to 1, video and audio get rendered
with their original speed. Slower playback, longer duration. Quicker
playback, shorter duration.
Note that $FPS is set to the unchanged original FPS of the input video,
as parsed from the output of ffprobe.
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