[pulseaudio-discuss] Extra A2DP codecs support in bluetooth module

[Pali Rohár]

On Wednesday 08 August 2018 10:06:19 Luiz Augusto von Dentz wrote:
> Hi Pali,
> 
> On Mon, Aug 6, 2018 at 11:03 AM, Pali Rohár <pali.rohar at gmail.com> wrote:
> > On Sunday 05 August 2018 15:59:05 ValdikSS wrote:
> >> On 30.07.2018 10:30, Pali Rohár wrote:
> >> > On Monday 30 July 2018 10:24:10 ValdikSS wrote:
> >> >>> ACL Data RX: Handle 256 flags 0x02 dlen 20               #109 [hci0] 5.421906
> >> >>       Channel: 66 len 16 [PSM 25 mode 0] {chan 2}
> >> >>       AVDTP: Get Capabilities (0x02) Response Accept (0x02) type 0x00 label 0 nosp 0
> >> >>         Service Category: Media Transport (0x01)
> >> >>         Service Category: Media Codec (0x07)
> >> >>           Media Type: Audio (0x00)
> >> >>           Media Codec: Non-A2DP (0xff)
> >> >>             Vendor ID: Cambridge Silicon Radio (0x0000000a)
> >> >>             Vendor Specific Codec ID: Unknown (0x0001)
> >> >>         03 23                                            .#
> >> >>
> >> >>
> >> >> Am I misunderstanding the latest item? Is it not a FastStream?
> >> >
> >> > Yes, 0x0000000a/0x0001 is FastStream. "03" means that it supports both
> >> > sink and source, "2" means that it supports microphone source sampling
> >> > frequency 16kHz and "3" means that that is supports music sink sampling
> >> > frequency 48kHz and 41.1kHz.
> >> >
> >>
> >> How did you understand that? Do you have a documentation?
> >> I'm writing Wireshark protocol dissector and want to include FastStream too.
> >
> > Hi! Look at https://patchwork.freedesktop.org/patch/241444/ patch, into
> > file a2dp-codecs.h. I put there a2dp_faststream_t and FASTSTREAM_*
> > defines, so it should be enough for writing dissector.
> 
> It doesn't look like we have FastStream decoding support in btmon either:
> 
> https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/monitor/a2dp.c#n50

I think that all needed information for decoding those packets is in
that pulseaudio patch in a2dp-codecs.h file. So if somebody is going to
write dissector and would not be able to decode something, just ask me.

-- 
Pali Rohár
pali.rohar at gmail.com