VLC not recognising HE-AAC audio stream

[ljbade]

Im trying to play back some Windows Media Center recorded TV files in VLC.

The files play back the H.264 correctly, but not the audio which is in HE-AAC.
The codec info window just shows "undf" for those streams and I get no audio.

If I play back clips from shows that have 5.1 AC3 tracks then it works, its just the stereo channels which use HE-AAC.

[Jean-Baptiste Kempf]

Please, share the file

[ljbade]

It is quite a large files (several GBs).

Is there a way to crop the video to a smaller size?

[Lotesdelere]

It is quite a large files (several GBs).
Is there a way to crop the video to a smaller size?

Use DGsplit and read here about how to do it:
viewtopic.php?f=14&t=57724&p=193335#p193335

Please, cut a short sample of this file, 20-30 MB will be enough, and upload it to some file sharing site, I suggest Multiupload.com because it will automatically upload the file to several other hosts for you, and then post the link to the file here.

[ljbade]

Can someone host dgsplit12.zip as the original website appears to be down.

[Lotesdelere]

It's not down, I just downloaded the tool from the original site.
Anyway, you can find it here too: http://www.multiupload.com/BWRS6VYYA7

[ljbade]

I have uploaded a 30MB clip of a recording that has the missing audio: http://www.multiupload.com/NMU1BJ8NN1

EDIT:
Heres the log from VLC for that file too BTY: http://pastebin.com/jzD65FGQ

[Jean-Baptiste Kempf]

Wtv files are not really supported in VLC.

[ljbade]

Wtv files are not really supported in VLC.

Why is that? It seems to work OK except for it not recognising the audio codec correctly.

[Jean-Baptiste Kempf]

Because noone has done any work on it, so far

[ljbade]

Hmm maybe I should fix that then, at least for the audio codec.

[ljbade]

OK looking at the sources, it is libavformat that handles WTV.

WTV appears to use a GUID to ID a codec, so I assume that the GUID for HE-AAC is not configured in libavformat.

How do I get the debug print from libavformat in the VLC log? libavformat prints the offending GUID to debug but somehow VLC doesn't log it.

[ljbade]

I have narrowed the missing code to: http://git.videolan.org/?p=ffmpeg.git;a ... =HEAD#l330

It only has MPEG Layer 2, AC3, Extended AC3, and ATRAC. Looks like AAC needs to be added.

[ljbade]

OK I finally got gdb working with this.

The two new GUIDs:
H.264: {0x48,0x32,0x36,0x34,0x00,0x00,0x10,0x00,0x80,0x00,0x00,0xAA,0x00,0x38,0x9B,0x71}
AAC: {0x02,0x16,0x00,0x00,0x00,0x00,0x10,0x00,0x80,0x00,0x00,0xAA,0x00,0x38,0x9B,0x71}

[ljbade]

It turns out that avformat and avcodec correctly recognize the stream as CODEC_ID_AAC_LATM but VLC doesn't.

[Jean-Baptiste Kempf]

yep, modules/codec/avcodec/fourcc.c is the culprit.

[ljbade]

fourcc.c
Needs this:
{ VLC_CODEC_MP4A, CODEC_ID_AAC_LATM, AUDIO_ES },
added to line 305.

I compiled this using 1.1.9 and it loads the file, but I still don't get any sound. The log is full of:
faad warning: Channel coupling not yet implemented

I can't test this modification against the Git master as it won't build.

Could someone please try this modification on Git and see if it plays my file correctly?

[Jean-Baptiste Kempf]

it won't work, But I have an idea how to fix, though...