sound: latency and synchronization measurements

[Muni Sekhar]

On Fri, May 18, 2018 at 6:42 PM, Greg KH <greg at kroah.com> wrote:
> On Fri, May 18, 2018 at 06:07:29PM +0530, Muni Sekhar wrote:
>> [ Please keep me in CC as I'm not subscribed to the list]
>>
>> Hi All,
>>
>> I am trying to characterize the audio synchronization between two
>> systems. There is a mechanism to route audio between two systems, we
>> run ‘aplay’ at one system and ‘arecord’ in other system.
>>
>> We need to measure the time difference when audio sample is out at one
>> port and arriving at another port in different system.
>>
>> I plan to add printk’s in “struct snd_pcm_ops” call backs, but does
>> these call backs tells when it received first and last audio
>> frames\samples?
>>
>> Or else please suggest any other best method.
>
> First off you need a "shared timer/clock" between the two systems in
> order to have a chance to determine what actually happens here.  Good
> luck with that!  :)
Yes, we do have the shared clock.

>
> Also, there's been tons of research in this area over the years, please
> look into that, odds are these problems have been solved already.  I
> know of several commercial devices that already handle this just fine.
>
Can you point me some information on this.


> best of luck!
>
> greg k-h



-- 
Thanks,
Sekhar