HE-AAC files not opening correctly

[mveras]

I have some files, in HE-AACv2 format recorded from the same exact source using same exact settings. Normally, these files do not open correctly in Adobe Audition. However, one of them opens correctly, that's the odd thing. On the files that do not open correctly, there are no error messages, but when they open, Audition opens it as a mono file and plays it at half the speed. The files were recorded with a stream recorder software. They are all the same exact size (27MB). Below is the information from MediaInfo comparing one that opens fine, and the other that does not. The only difference I see is the file name, everything else seems identical. However, Audition does not like the second file (05-21). I am using Audition 2020. I have many other files same exact format that Audition does not like, but the first one listed below (05-20), for some reason opens fine in Audition. I open all files just fine in the free Audacity editor, and they work fine in any player I try. So I don't think there's any corruption going on. Only Audition seems to have a problem with these files. My workaround for now is to use Audacity (3rd party free software) or to convert them to another format prior to edit them with Audition, or use the pitch tool in Audition to speed up the clip to 50% and increase the semitones to 12 to restore the audio to original state, however, I lose the stereo channel that way. Any ideas?

General
Complete name : 05-20_unedited.aac
Format : ADTS
Format/Info : Audio Data Transport Stream
File size : 26.4 MiB
Overall bit rate mode : Variable

Audio
Format : AAC LC SBR PS
Format/Info : Advanced Audio Codec Low Complexity with Spectral Band Replication and Parametric Stereo
Commercial name : HE-AACv2
Format version : Version 4
Format settings : Implicit
Codec ID : 2
Bit rate mode : Variable
Channel(s) : 2 channels
Channel layout : C
Sampling rate : 44.1 kHz
Frame rate : 21.533 FPS (2048 SPF)
Compression mode : Lossy
Stream size : 26.4 MiB (100%)

General
Complete name : 05-21_unedited.aac
Format : ADTS
Format/Info : Audio Data Transport Stream
File size : 26.4 MiB
Overall bit rate mode : Variable

Audio
Format : AAC LC SBR PS
Format/Info : Advanced Audio Codec Low Complexity with Spectral Band Replication and Parametric Stereo
Commercial name : HE-AACv2
Format version : Version 4
Format settings : Implicit
Codec ID : 2
Bit rate mode : Variable
Channel(s) : 2 channels
Channel layout : C
Sampling rate : 44.1 kHz
Frame rate : 21.533 FPS (2048 SPF)
Compression mode : Lossy
Stream size : 26.4 MiB (100%)

[SteveG_AudioMasters_]

It's not Audition itself that has the problem - it's whatever is decoding these files to wav files, which is Audition's internal format - I suspect the Windows Media Foundation decoder is the likely culprit. There are all sorts of other options in the metadata that don't show in these comparisons - we'd have to look at the individual files - or better, get the devs to do it.

[SteveG_AudioMasters_]

I think that on balance, what you should probably do is send an email to audbugs@adobe.com and include with it a working and non-working file. That way it will get looked at directly by the devs. Make sure that you include contact details.

[_durin_]

Thanks for sending the links to those files.

I find I can import both of them, but see the different behaviors.  Audition appears to import both files through the ImporterMPEG plugin by default, which I believe may feed through a third party codec library.  On MacOS we can utilize Apple's native codecs, but Windows requires a third-party implementation to open these files.

With the "iHeart Broadway" file, it opened as a mono 44.1K file and playback sounded half-speed.   I was able to quickly compensate by selecting Edit > Interpret Sample Rate and choosing 88,200.  On MacOS, when I force it to import through the native "Apple Audio Toolbox" option in the Open File dialog, it is imported as a stereo file at the correct speed.  My hunch is the channel data is interleaved and the default "ImporterMPEG", which I believe utilizes third party codecs by MainConcept, is being interpreted as a single channel which explains why it's half-speed and one channel.

The "Magic at the Musicals" opened as a stereo file and played back at the correct rate, but was highly overdriven and clipped.  I was able to bring the levels down, though because the source wasn't 24/32-bits, the clipped samples are flattened rather than being restored.  When I forced this import through the Apple codecs, it opened fine again, but reducing amplitude did restore the waveform fully.

You can see in the screenshot, the files have some different characteristics.  The first is MPEG-4 HE AAC vs, but the second is standard AAC.  I'll ask the team to investigate how Windows support for these files differs from Apple's codecs.

edit: I don't know why the forum won't embed the image.  I've attached it as well, but it isn't showing up for me at the moment.

[itsamike]

We seem to have the exact same taste in programming, as I record the same two stations (and others), probably with the same stream recording software (though I can recommend alternatives), and I have the very same problem. Well, not entirely. IHRBroadway has the same half-speed mono issue, and for that I use Audacity to open and do most of the cleanup I like to do, and if there's anything I can't do, I export to WAV and open that in Audition. For Magic at the Musicals, I use the high-quality 128k stream and haven't had any issues.

If you want to compare notes directly, without clogging up the forum, I'd be happy to share additional URL and software options, and regale you with tales of the private podcasts I turn those shows into for my wife's listening enjoyment.