Bug#786660: pulseaudio-module-bluetooth: Cracky sound when something else runs

[Felipe Sateler]

On 30 May 2015 at 16:18, Julien Palard <julien at palard.fr> wrote:
> o/
>
> First thanks for your time,  it helped a lot:
>
> On 05/30/2015 01:24 AM, Felipe Sateler wrote:
>>
>> What parameters are you giving to the loopback module? I see in the log:
>>
>> source="bluez_source.C4_43_8F_9F_F5_36" source_dont_move="true"
>> sink_input_properties="media.role=music"
>>
>> Is that all?
>
>
> It was just:
>
> pactl load-module module-loopback source=bluez_source.C4_43_8F_9F_F5_36
> sink=alsa_output.pci-0000_00_1b.0.analog-stereo
>
>> Try increasing the latency (default is 200), or disabling remixing.
>>
>> If that fails, try changing the resampler in the configuration file.
>
> I tried with latency-msec=2000 -> same
> I tried (keeping latency-msec=2000) to add remix=false -> A little bit
> better, not sure.
> I tried to set `resample-method = src-sinc-best-quality` -> That's GOOD !
> I'm reverting to a default value to remix (not sure it's true) -> Still good
> !
> I'm reverting to the default value of 200 for latency-msec -> Still perfect
>
> So it's the resample-method, it was not set in my configuration, only
> commented, maybe the default ? Was:
>
> ; resample-method = speex-float-1
>
> I tried to find for you which resample-method was picked with this magical
> "best-quality" mode, and I found this in syslog:
>
> resampler.c: Support for resampler 'src-sinc-best-quality' not compiled in,
> reverting to 'auto', so I tried pulseaudio -vvv and got:
>
> D: [pulseaudio] resampler.c: Resampler:
> D: [pulseaudio] resampler.c:   rate 44100 -> 44100 (method speex-float-1)
> D: [pulseaudio] resampler.c:   format s16le -> s16le (intermediate
> float32le)
> D: [pulseaudio] resampler.c:   channels 2 -> 2 (resampling 2)
>
> Hope that's helps ? Tell me if you need more information / debugs / logs /
> tests / whatever.

Hmm, I see in the old logs:

(   1.028|   0.000) D: [pulseaudio] resampler.c: Resampler:
(   1.028|   0.000) D: [pulseaudio] resampler.c:   rate 44100 -> 25
(method peaks)
(   1.028|   0.000) D: [pulseaudio] resampler.c:   format s16le ->
float32le (intermediate s16le)
(   1.028|   0.000) D: [pulseaudio] resampler.c:   channels 2 -> 1
(resampling 1)

This looks wrong to me. However, I don't think I can be of more help
as my knowledge is limited in this regard. Could you please bring this
up at the upstream list or bug tracker? They will have better
understanding, and maybe a fix can be made to choose a better
resampler by default.

If you do so, please report back to this bug the link to the upstream report.


-- 

Saludos,
Felipe Sateler