MP4 with AAC SBR+PS sound distortion.

I’m getting audio distortion when playing back MP4 files. They sound perfectly fine in quicktime player & vlc on my mac.

I suspect the issue is with AAC PS (parametric stereo) extension. There is no problem with video playback at all.

The files are MP4.

Video track: H.264 MPEG-4 AVC (part 10) (avc1). 

Audio track: MPEG AAC Stereo 48 Khz with AAC extensions SBR+PS

I’ve got the current infuse player version on the ATV2.

Has anyone run into a problem SBR+PS AAC audio tracks? Are they supposed to be supported?

Any chance you’d be able to send in a sample file?

Yes - how shall I send that? The files are shorts, so one is around 20MB.

Now that I think about it, maybe the mix of L R and 2 C channels is the problem for infuse, even though these files play great using XBMC on the same ATV.

Also more info via mediainfo on one of the problem audio tracks. :



ID                                       : 2

Format                                   : AAC

Format/Info                              : Advanced Audio Codec

Format profile                           : HE-AACv2 / HE-AAC / LC

Codec ID                                 : 40

Duration                                 : 12mn 37s

Bit rate mode                            : Variable

Bit rate                                 : 40.0 Kbps

Maximum bit rate                         : 44.9 Kbps

Channel(s)                               : 2 channels / 1 channel / 1 channel

Channel positions                        : Front: L R / Front: C / Front: C

Sampling rate                            : 48.0 KHz / 48.0 KHz / 24.0 KHz

Compression mode                         : Lossy

Delay relative to video                  : 83ms

Stream size                              : 3.61 MiB (14%)

Encoded date                             : UTC 2012-10-10 12:29:36

Tagged date                              : UTC 2012-10-10 12:29:36


Hmm, that could be part of it. 4ch audio tracks aren’t very common, but it’s definitely worth taking a look at.

If you’re able to upload a sample to something like Dropbox and PM me the link, that would be super-helpful. :slight_smile: