[pulseaudio-discuss] bluetooth latency gets gradually worse over time

[mudrunka at spoje.net]

Ok,
i've filled bug:
https://bugs.freedesktop.org/show_bug.cgi?id=95411

Dne 2016-05-02 22:13, mudrunka at spoje.net napsal:
> Dne 2016-05-02 16:53, Jerome Leclanche napsal:
>> On Mon, May 2, 2016 at 5:06 PM, Arun Raghavan <arun at accosted.net> 
>> wrote:
>>> On 1 May 2016 at 08:07,  <mudrunka at spoje.net> wrote:
>>>> Hello,
>>>> i have issue with bluetooth speaker. it creates loud pop when it's
>>>> (un)suspended by module-suspend-on-idle. so i proceeded to disable
>>>> suspend-on-idle, but when i leave it on for few hours, the latency 
>>>> gets
>>>> huge. Like 2 seconds or more. I suppose it has something to do with 
>>>> DAC
>>>> clock (or samplerate) in bluetooth speakers being little bit slower 
>>>> than
>>>> nominal. And the error adds up over time resulting in growing 
>>>> latency.
>>>> 
>>>> When i manualy reconnect to speaker it gets fixed.
>>>> 
>>>> Do you have any idea how to fix this? I think it needs something 
>>>> that will
>>>> reset the stream when no audio is played, pretty much like 
>>>> suspend-on-idle
>>>> does, but without powering the bt device off (which causes pop). 
>>>> it's really
>>>> annoying. sometimes it scares the crap out of me, when speakers are 
>>>> on full
>>>> volume and it pops when i eg. receive IM mesage. :-) also it's 
>>>> probably not
>>>> healthy for the speakers (i use conventional speakers with amp and 
>>>> bt
>>>> receiver).
>>>> 
>>>> I know the popping is mostly HW error. But it can be worked around 
>>>> by
>>>> disabling suspend-on-idle, which then causes latency problems (also 
>>>> somehow
>>>> HW related). And i think the latency problem can be somehow fixed in 
>>>> SW by
>>>> restarting the stream or cleaning some buffer that causes the 
>>>> latency...
>>>> 
>>>> BTW 2 seconds of latency are quite a lot... Is there even chance, 
>>>> that cheap
>>>> BT device has 2 second buffer? Maybe it's pulse audio that has 2 
>>>> second
>>>> latency. And it would be easily fixed by not buffering silence. Or 
>>>> by
>>>> deleting this buffer when idle.
>>> 
>>> That does sound like a large latency. Could you file a bug about 
>>> that,
>>> and hopefully I'll get some time to test this out to see if it 
>>> happens
>>> locally too? If we do fix that, it looks like your problem should 
>>> just
>>> be fixed.
>>> 
>>> Cheers,
>>> Arun
>>> _______________________________________________
>>> pulseaudio-discuss mailing list
>>> pulseaudio-discuss at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
>> 
>> I missed that original email, but this is something that's familiar to 
>> me.
>> I've been able to reproduce this exact issue very easily on the
>> bluetooth Parrot Zik and Parrot Zik 2 models with my btusb receiver by
>> running out of range of the receiver.
>> When out of range, a popping sound can be heard while the sound cuts
>> for a few milliseconds, and the sound then resumes where it initially
>> left off, creating a latency buffer which keeps growing every time the
>> headset goes out of range again.
>> The buffer resets when the card profile is turned off and back on (eg.
>> pactl set-card-profile bluez_card.... off && pactl set-card-profile
>> bluez_card.... a2dp_sink).
>> 
>> Worth noting the issue does not happen on the Parrot Zik 3, which is
>> compatible with Bluetooth 4.x (unlike the versions 1 and 2).
>> 
>> J. Leclanche
> 
> 
> So do you think it will be possible to easily fix this in software for 
> BT 2?
> I think you are true that it's related to the signal. I think i've
> noticed it gets worse during signal disturbances...
> 
> Tomas
> 
> 
>> _______________________________________________
>> pulseaudio-discuss mailing list
>> pulseaudio-discuss at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
> 
> _______________________________________________
> pulseaudio-discuss mailing list
> pulseaudio-discuss at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss