Stero / Mono

[GoogleCodeExporter]

I Use this url
http://173.192.207.51:8036

but listening on headphones the signal looks like it is mono.
Is decoders converts the stream to mono or stereo.

Original issue reported on code.google.com by dimovdan...@gmail.com on 23 Feb 2012 at 3:36

• Blocking: #7

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Please try version 0.6 if it is better and let me know, please.
Thanks

Vaclav

Original comment by vbarta...@gmail.com on 14 Jun 2012 at 7:29

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Some AAC+ streams use a feature called Parametric Stereo (PS). Unfortunately 
OpenCORE library is crashing with this feature enabled. So I had to disbale it, 
so this stere/mono problem can be caused by this.

Unfortunately I am not able to fix the problem in OpenCORE unless know the PS 
specification / exact algorithm. 

Vaclav

Original comment by vbarta...@gmail.com on 15 Jun 2012 at 7:09

• Added labels: Component-Native

[GoogleCodeExporter]

Tha crashing of the library can be fixed by this patch, but unfortunately it 
seems, that it does not improve the result stream (still mono). Also sometimes 
the output to the right headphone is broken:

http://androidxref.com/source/xref/frameworks/base/media/libstagefright/codecs/a
acdec/sbr_dec.cpp?r=a2e29968abe003f1b92ea9cbff5e70c77f28be34

Original comment by vbarta...@gmail.com on 16 Jun 2012 at 4:05

[GoogleCodeExporter]

After learning PS algorithm and debugging the opencore-aacdec library it seems 
I've found the root cause. PS decoder is not correctly initialized.
So, the solution exists, now we need only to apply the changes to the project 
and test it thoroughly.
Look forward for the next release 0.7

Vaclav

Original comment by vbarta...@gmail.com on 28 Jun 2012 at 2:43

• Changed state: Started
• Added labels: Priority-High
• Removed labels: Priority-Medium

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Original comment by vbarta...@gmail.com on 28 Jun 2012 at 3:05

[GoogleCodeExporter]

Original comment by vbarta...@gmail.com on 28 Jun 2012 at 3:07

• Now blocking: #7

[GoogleCodeExporter]

Revision #19
------------------------------------------------------------------------------
2012-06-28 by Vaclav Bartacek
    Fixed Parametric Stereo initialization bug.
    All HE-AAC+ streams played mono.

    Bugfix(1) - if PS extension is found in the first frame, then the PS
        decoder is initialized, but the stream type was not correctly set
        to MP4AUDIO_PS (remained MP4AUDIO_SBR)

    Bugfix(2) - if PS extension was not found in the first frame, then PS
        decoder was not initialized at all.

    Files:
        codecs_v2/audio/aac/dec/src/sbr_applied.cpp

------------------------------------------------------------------------------
2012-06-16 by Vaclav Bartacek
    Applied patch found in standard Android branch.
    Bugfix - when enabled Parametric Stereo, then crashing.

    Files:
        codecs_v2/audio/aac/dec/src/sbr_dec.cpp

------------------------------------------------------------------------------

Original comment by vbarta...@gmail.com on 28 Jun 2012 at 7:47

• Changed state: Fixed

Attachments:

• sbr_dec.cpp
• sbr_applied.cpp