Re: possible sbc codec bug with audio glitches

[Jelle de Jong <jelledejong@powercraft.nl>]

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Brad Midgley wrote:
> Jelle,
> 
> Everything in the codec is symmetrical between the two channels unless
> using joint stereo mode. In joint stereo, if it saves space, we encode
> the difference between and the sum of the channels instead of the
> individual channel content. It's conceivable that an overflow here
> might be manifest differently between the two channels.
> 
> It looks like you can use a parameter "mode" in the alsa config and
> set it to either "stereo" or "joint"
> 
> If you can narrow down the distortion to one of these cases that would be handy.
> 
> Do you have an mp3 I could try to hear the problem?
> 
> Brad

Thank you Brad for taking the time to answer.

I have tried the mode joint and mode stereo [1] for a few days but I
cant hear any difference and the small glitches are still there.

I posted a small audio segment that has the problem in my first post:
http://sourceforge.net/mailarchive/message.php?msg_name=4819B1A7.2070702%40powercraft.nl
http://filebin.ca/pugrs/glitch.wav

Thanks in advance,

Jelle

> On Sun, Nov 16, 2008 at 2:37 PM, Jelle de Jong
> <jelledejong@powercraft.nl> wrote:
>> Brad Midgley wrote:
>>> Jelle
>>>
>>>> The strange thing is that I can only hear the glitches on the right side
>>>> of the headset.
>>> That is very strange it is only on one side. Do you know if you were
>>> you using the joint stereo setting in the codec?
>>>
>> Thank you Brad for taking the time to read and answer to my question,
>> this is really appreciated. I dont exactly know what you mean with joint
>> stereo settings in the code?
>>
>> I use the bluez git build on 2008-11-06. The only info I got is from the
>> bluetoothd running in debug mode, please see the attachment for more
>> information.
>>
>> I hope the below section is the most relevant?
>>
>> config a2dp - device = 00:0C:55:D1:C9:78 access_mode = 2
>> codec sbc - frequency = 1 channel_mode = 1 allocation = 1 subbands = 1
>> blocks = 1 bitpool = 44
>> a2dp_source_config: selected SEP 0xb81b1020
>> avdtp_ref(0xb81acbf0): ref=3
>> setup_ref(0xb81b62a8): ref=1
>> avdtp_set_configuration(0xb81acbf0): int_seid=1, acp_seid=1
>>
>> Thanks in advance,
>>
>> Jelle

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