[pulseaudio-discuss] Bluetooth aptX codec

[ValdikSS]

I can't find any information regarding CSR True Wireless Stereo v3. What's that? Can you share documentation where you got information about these IDs?

On 19.12.2018 20:59, Pali Rohár wrote:
> On Thursday 09 August 2018 16:39:09 ValdikSS wrote:
>> 0xFF 0x000A 0x0103 — Unknown codec found on Bose QuietComfort QC35 II
> "The CSR True Wireless Stereo v3 Codec ID for SBC."
>
>> Value hex dump: 07 06 00 00 ff ff 02 35
> From information which I have, info payload is just embedded AVDTP media
> capability buffer.
>
> 07 - AVDTP_SERVICE_MEDIA_CODEC
> 06 - length
>
> 00 - AVDTP_MEDIA_TYPE_AUDIO
>
> 00 - A2DP_CODEC_SBC
> ff - SBC_CHANNEL_MODE_JOINT_STEREO | SBC_CHANNEL_MODE_STEREO |
>      SBC_CHANNEL_MODE_DUAL_CHANNEL | SBC_CHANNEL_MODE_MONO |
>      SBC_SAMPLING_FREQ_48000 | SBC_SAMPLING_FREQ_44100 |
>      SBC_SAMPLING_FREQ_32000 | SBC_SAMPLING_FREQ_16000
> ff - SBC_BLOCK_LENGTH_4 | SBC_BLOCK_LENGTH_8 |
>      SBC_BLOCK_LENGTH_12 | SBC_BLOCK_LENGTH_16 |
>      SBC_SUBBANDS_4 | SBC_SUBBANDS_8
>      SBC_ALLOCATION_SNR | SBC_ALLOCATION_LOUDNESS
> 02 - min bitpool
> 35 - max bitpool
>
> So it matches SBC definition buffer as expected.
>
>> 0xFF 0x000A 0x0104 — Unknown codec found on Bose QuietComfort QC35 II
> "The CSR True Wireless Stereo v3 Codec ID for AAC."
>
>> Value hex dump: 07 08 00 02 c0 ff 8c 84 e2 00
> Again, it should be embedded AVDTP media capability buffer.
>
> 07 - AVDTP_SERVICE_MEDIA_CODEC
> 08 - length
>
> 00 - AVDTP_MEDIA_TYPE_AUDIO
>
> 02 - A2DP_CODEC_MPEG24
> c0 - AAC_OBJECT_TYPE_MPEG2_AAC_LC | AAC_OBJECT_TYPE_MPEG4_AAC_LTP |
>      AAC_OBJECT_TYPE_MPEG4_AAC_SCA
> ff 8c - frequences: all; channels: all
> 84 e2 00 - VBR; bitrate: 320000
>
> So also MPEG2/4 AAC buffer is correct.
>
>
> Moreover there also exist these codecs:
>
> 0xFF 0x000A 0x0105 - The CSR True Wireless Stereo v3 Codec ID for MP3.
> 0xFF 0x000A 0x0106 - The CSR True Wireless Stereo v3 Codec ID for AptX.
>
> And again capability buffer should contain embedded AVDTP media
> capability buffer for MPEG1 (with Layyer 3) and for aptX.
>

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