Is there a way to dump compressed audio in a playable format? (without re-encoding)

[salamanders]

The original post says "We found that it is essentially HE-AAC with some modifications".

I wasn't sure if it was possible to output HE-AAC files in a mp4 wrapper, without having to decode-to-wav-reencode-to-AAC.

[icb-]

You can output the HDC stream with the --dump-hdc <path> option. Unfortunately, this isn't directly playable with unpatched decoders.

There used to be code to convert that stream to a standard ADTS, but it was removed as "unsupported". It's still in the Git history, and you can build it. See a comment on issue 88 for how to get it and build it. This seems to be mostly playable by software like VLC and ffmpeg, but may have some decoding and audio issues.