> > ffmpeg -y -f concat -safe 0 -copyts -i videoList.txt -muxpreload 0 > > -muxdelay 0 -c copy -b:a 128K -cpu-used 0 -preset slow -movflags > > +faststart -f mp4 concat.mp4 > Make one file out of ??? files. Does this also re-encode anything? (What are > the input formats? see below) > > > ffmpeg -y -i concat.mp4 -itsoffset 1.9 -i concat.mp4 -c:a aac -c:v > > copy -map 0:v:0 -map 1:a:0 -f mp4 audioFixed.mp4 > Shift the audio a bit and re-mux. > > > ffmpeg -y -i audioFixed.mp4 -ss 2 -to 17 -c:v copy -c:a aac -f mp4 > > final.mp4 > Select part of the now-shifted file. > > > Sometimes, there is no gain to creating more complex directives. In this > case, it might reduce the amount of de/remux work, but the time-shift > suggests pretty much means you're stuck with intermediate file(s). Might > combine the 2nd and 3rd commands. > > Since you only select 17 seconds from the output, you could add a 20 second > limit to the first step, which would potentially make the intermediate files > smaller. (Another thing we don't know.) > > Consider using another _container_ type for the intermediate file(s) (e.g. > nut, avi, or mkv, which can hold the mp4 data). > > You could also, in the first pass, write to separate files for audio and > video, > which might simplify the shift/remux process and then apply the time-based > selection to that (see > https://trac.ffmpeg.org/wiki/Creating%20multiple%20outputs). > > Move the "faststart" to the last step since that's where it would matter (it > gets in the way of piping, if used, and it adds a second file write pass). > > I haven't yet tried any of this, and there's probably an error somewhere in > there. > > As usual, it really helps to see the command output so we know the file > formats/etc. > > z!
Many thanks for your detailed reply! It helps us a lot. Best, RS _______________________________________________ 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".
