OGG data issue

[m1dst]

If I download an OGG file with no transcoding, the file seems to play everywhere however I have found a couple of apps that have trouble processing the files.

Simple example is ffmpeg.

.\ffmpeg -i source.ogg destination.ogg

The example above fails badly with the source file.

If I change the destination to an m4a file...

Whilst I am not trying to use these commands in real life, I just wanted a reproducible example because you wont have access to the tool I was trying to load the files in to. I was going to write a script just to transcode them and then I found ffmpeg failed too.

Hope that is enough information.

[Rafiuth]

I've been able to transcode to M4A with this command: ffmpeg -i source.ogg -disposition:v attached_pic -c:v copy output.m4a, but it won't copy metadata for some reason.

I noticed that ffmpeg always shows this non-monotonous DTS warning, even for new oggs:

ffmpeg -i sample.wav reenc.ogg
ffmpeg -i reenc.ogg reenc2.ogg

[...]
Output #0, ogg, to 'reenc2.ogg':
  Metadata:
    encoder         : Lavf59.16.100
  Stream #0:0: Audio: vorbis, 44100 Hz, stereo, fltp
    Metadata:
      encoder         : Lavc59.18.100 libvorbis
[libvorbis @ 00000211cdc5e100] Queue input is backward in time
    Last message repeated 6 times
[ogg @ 00000211cdc5d140] Non-monotonous DTS in output stream 0:0; previous: 92224, current: 91904; changing to 92224. This may result in incorrect timestamps in the output file.
[ogg @ 00000211cdc5d140] Non-monotonous DTS in output stream 0:0; previous: 92224, current: 92032; changing to 92224. This may result in incorrect timestamps in the output file.
[ogg @ 00000211cdc5d140] Non-monotonous DTS in output stream 0:0; previous: 92224, current: 92160; changing to 92224. This may result in incorrect timestamps in the output file.
[libvorbis @ 00000211cdc5e100] Queue input is backward in time
    Last message repeated 3 times
[...]

From the log above and a quick look at ffmpeg's source, I think there's a bug on the ogg demuxer (multiple packets are stored in one ogg page, and it seems that the demuxer assigns the same DTS to all of them).

I'd appreciate if you could convert some file to wav and back to ogg and test with your app to confirm this is a soggfy issue.

[m1dst]

I confirm that if I convert a broken ogg to wav and then back to ogg, the file is readable by the tool.