[FFmpeg-user] Concat demuxer avoid injecting additional silent packets

[Ronak]

> On Oct 10, 2022, at 10:43 PM, Ronak via ffmpeg-user <ffmpeg-user at ffmpeg.org> wrote:
> 
> Hi,
> 
> I’m trying to concatenate a bunch of audio only MP4s together using FFmpeg’s concat demuxer.
> 
> When I tested this with concaving 4 MP4 files into a larger one, FFmpeg seems to inject a variable amount of audio samples between concatenated files.
> 
> Is there a way to avoid having FFmpeg inject those additional silent packets while concatenating?

Here is my FFmpeg information:

ffmpeg version N-95714-g20c5f4d835 Copyright (c) 2000-2019 the FFmpeg developers
  built with Apple clang version 13.1.6 (clang-1316.0.21.2.5)
  configuration: --enable-gpl --enable-nonfree --enable-libfdk-aac --enable-libmp3lame --enable-libopus --disable-encoders --enable-encoder='aac,ac3,ac3_fixed,eac3,flac,libfdk_aac,libmp3lame,libopus,pcm*' --disable-decoders --enable-decoder='aac,ac3,ac3_fixed,eac3,flac,libfdk_aac,libmp3lame,libopus,pcm*,mp3*,mpeg*' --disable-muxers --enable-muxer='ac3,adts,dash,eac3,flac,hls,mp3,mp4,mpegts,null,opus,wav,caf' --disable-demuxers --enable-demuxer='aa,aac,ac3,dash,eac3,flac,hls,mov,mp3,mpegts,pcm*,concat,wav,caf' --prefix=/Users/ronakp/ffmpeg

And the command I’m running:

ffmpeg -f concat -safe 0 -i concat.txt -c copy output_concat_chopped.mp4 -loglevel debug

And the contents of the concat.txt file

file 'output1.mp4'
file 'output2.mp4'
file 'output3.mp4'
file 'output4.mp4'


> 
> Does FFmpeg inject this silence regardless of what output there is? (Raw AAC vs AAC in MP4).
> 
> Ronak
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
> 
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".