On Sun, 13 Mar 2016, Oleksij Rempel wrote:

> Am 13.03.2016 um 16:30 schrieb Alan Stern:
> > On Sun, 13 Mar 2016, Oleksij Rempel wrote:
> > 
> >> Hallo all,
> >>
> >> i need to sync device clock with host clock, since device will return
> >> SOF counter for each packet i need to use it as reference. Are there any
> >> proper way to convert SOF to a host timestamp?
> > 
> > No, there isn't.  There is no relationship between the SOF packet
> > arrival time or frame number and the host's time.
> > 
> > Alan Stern
> > 
> 
> Hm... Usb Vidoe Class specification suggest to use Source Time Clock
> (some internal clock) value connected with SOF number to get actual
> Frame timestamp. At same time bDealy from audio descriptor should be
> used to sync audio and video. If i see it correctly, bDelay is expressed
> in SOF or milliseconds as well. So if only way to Sync both streams is
> SOF, how can it be made?
> Is it possible to get at least SOF number of received packet?

That depends on the firmware in your device.  The host has nothing to 
do with it.

Alan Stern

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