Certain ISO-MP4 files have their audio track decoded as junk

[marin-m]

See marin-m/SongRec#263 for a sample test file

Also, when I just disable the MP4 decoding backend in the Rodio create features it will still try to incorrectly decoding using the MP3 then the WAV decoder (??), I need to disable these too to have Rodio try other backends.

Perhaps related to #475 / #332?

Regards,

[sscobici]

The provided sample is HE-AAC, which Symphonia does not yet support. See PR #473 for HE-AAC and HE-AAC v2 support.

[pdeljanov]

The decoded audio is not junk. HE-AAC/HE-AACv2 is a form of progressive enhancement. Without a decoder that supports it, it decodes at half the sample rate.

As for the probing issue, that's an chronic issue that's difficult to solve. As you de-register format readers, the probe starts to get lobotomised. If the MP4 has a byte sequence that matches that of a MP3 header, then the MP3 reader can get chosen. The v0.6.0-alpha.2 version of Symphonia should improve this, however, Rodio is stuck on the stable v0.5.5 release until the next version is released, and they update to the newer APIs.