On Sun, Jun 19, 2016 at 12:45:50AM +0200, Henrik Austad wrote:
edit: this turned out to be a somewhat lengthy answer. I have tried to shorten it down somewhere. it is getting late and I'm getting increasingly incoherent (Richard probably knows what I'm talking about ;) so I'll stop for now.
Thanks for your responses, Henrik. I think your explanations are on spot.
note that an adjustable sample-clock is not a *requirement* but in general you'd want to avoid resampling in software.
Yes, but..
Adjusting the local clock rate to match the AVB network rate is essential. You must be able to *continuously* adjust the rate in order to compensate drift. Again, there are exactly two ways to do it, namely in hardware (think VCO) or in software (dynamic resampling).
What you cannot do is simply buffer the AV data and play it out blindly at the local clock rate.
Regarding the media clock, if I understand correctly, there the talker has two possibilities. Either the talker samples the stream at the gPTP rate, or the talker must tell the listeners the relationship (phase offset and frequency ratio) between the media clock and the gPTP time. Please correct me if I got the wrong impression...
Thanks, Richard