Audio clock / timestamps drift issue with internet streams

[Christophe Dongieux]

Hi,

I'm currently performing some tests with the sync property of alsasink set
to false.
It's not really perfect since instead of having audio blanks, I now have
some instants of audio being dropped (as there were missing words in a
sentence).

I'm not really satisfied with this, so I keep on investigating.

Cheers.

2011/12/6 Christophe Dongieux <christophe.dongieux at gmail.com>

> Hi,
>
> I'm running gstreamer on a device that is not a PC, and after some tests,
> it appears that the audio clock on this device is slower than it should be.
> The test to reveal this was to take an audio file and start playing it on
> both the device and a PC: the file is about 1 hour long, and at the end of
> it, there was about 1min30sec difference between the time the file ended on
> the device and on the PC (yeah, big drift!).
>
> In the case of a local file playing, this is not a big deal to be a little
> slower. But in the case of a live playing (in my case MMS radio), there is
> a drift between the internet stream time and alsasink (local) time, so
> alsasink starts complaining after about an hour with audio cuts and this
> message: "Unexpected discontinuity in audio timestamps of more than half a
> second".
>
> There are 2 aproaches to deal with this problem: understand and fix the
> audio clock rate, or make some tricks in gstreamer/alsasink to avoid the
> drift.
> In the case I can't find out the audio clock rate fix, do you have any
> idea what would be the tricks to make internet radios play fine and long on
> my device?
>
> I saw in alsasink plenty of properties that are related to the clock, but
> it is not really clear for me what could help me (documentation does not
> help me so much).
>
> Thanks in advance,
> Christophe Dongieux.
>
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