[Libav-user] Unimplemented container channel layout Bug

Bruce Wheaton bruce at spearmorgan.com
Mon Nov 14 18:08:36 CET 2011

I have a fairly simple .mov with one track of stereo PCM 16-bit audio. Quicktime has the channels tagged as left and right.

When I open the file with libavformat & libavcodec, I get the 'Unimplemented container channel layout' warning and it won't play properly (in my app).

If I re-save the audio in QT Player 7.6, it apparently tags the layout better, and it plays fine - no warning.

I don't see a 'chan' atom in the file, and this old fix seems related:


My isom.c looks like the patched version:

    if (layout_tag == 0) { // kCAFChannelLayoutTag_UseChannelDescriptions
        // Channel descriptions not implemented
        av_log_ask_for_sample(s, "Unimplemented container channel layout.\n");
        avio_skip(pb, size);

So - I wonder, did something else change that is preventing the patch from working? Is it something as simple as the default used to be 'stereo'? it looks like the code is meant to return if no layout is found, I imply that to mean return, leaving the movie as stereo? Does it now mean, return, leaving the movie as unknown?

I'm working on getting a sample that can be shared.

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