Re: [Bluez-devel] AVDTP socket?

[Brad Midgley <bmidgley@xmission.com>]

Marcel

Argh... I'm stuck again. the avdtp_set_configuration command goes out 
but reading the response just blocks. I'm not sure what is wrong... I send:

  00 -> header = request
  03 -> AVDTP_SET_CONFIGURATION
  04 -> acp_seid = 1
  04 -> int_seid = 1 (how should I choose the int_seid?)
  01 -> service category = media transport
  00 -> length of service capabilities = 0
  07 -> capability type = media codec
  06 -> bytes remaining? not sure if this is right.
  00 -> media type = audio media type
  00 -> media codec type = SBC
  22 -> 44.1khz stereo
  15 -> 16-byte blocks, 8 subbands, "loudness" allocation
  02 -> min bitpool
  fa -> max bitpool

a2play.c in cvs contains the code I'm trying...

Brad

Marcel Holtmann wrote:
> Hi Brad,
> 
> 
>>>>The accept looks like this byte-for-byte:
>>>>
>>>>02 -> response accept
>>>>02 -> AVDT_GET_CAPABILITIES
>>>>01 -> category = media transport
>>>>00 -> length of service capabilities = 0
>>>>07 -> 7 'elements' follow
>>>>06 -> elements[0]
>>>>00 ->
>>>>00 ->
>>>>ff ->
>>>>ff ->
>>>>02 ->
>>>>fa -> elements[6]
>>
>>>this should be the codec specific part. Look at A2DP for more details.
>>
>>It doesn't totally seem to match up. The last 4 bytes seem to be the 
>>capabilities of SBC (p.20 of a2dp)
>>
>>ff -> supports all sampling frequencies, channel modes
>>ff -> supports all block lengths, subbands, allocation methods
>>02 -> minimum bitpool val
>>fa -> max bitpool val
>>
>>I can't find where the first 06, 00, 00 fit. Also, does the seid=1 in 
>>the avdtp_discover accept correspond to only supporting SBC? I wasn't 
>>expecting to know the supported codecs until after the first 
>>avdt_get_capabilities.
> 
> 
> I looked it up and the GET_CAPABILITIES response you get back contains
> two block. The first is the "media transport" with 0 bytes of additional
> information and the second is the "media codec" part with 6 bytes of
> codec specific information.
> 
> 	0x01 = media transport
> 	0x07 = media codec
> 
> The first 0x00 represents the "media type" and the second the "media
> codec type". And this means "audio" and "SBC". And the rest is SBC
> specific as you already recognized.
> 
> Regards
> 
> Marcel
> 
> 
> 
> 
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