[AG-TECH] query re: delay

Colin Perkins csp at csperkins.org
Mon Oct 2 03:42:56 CDT 2006


Hi,

On 2 Oct 2006, at 09:00, Andrew A Rowley wrote:
> In RAT, you can go to "Options..." then select "Reception" from the  
> top menu.  From here you can limit the playout delay to 1 second  
> (if I am reading it correctly).
>
> Playout delay in RAT is adaptive - my understanding of this is that  
> if there are lots of packets arriving late, it will increase the  
> delay until there is enough that most packets arrive within the  
> time of the playout delay.  I think that VIC does this too, but no  
> so aggressively, hence the difference between audio and video  
> delays.  I am guessing that you see lots of breaking up of the  
> video which would show that it is having to throw away lots of late  
> packets.

Also, do you have silence suppression turned on in rat? If not, and  
if the sender and receiver audio sampling clocks run at slightly  
different rates, delay can build up and result in the type of problem  
you're seeing (rat compensates for mismatched sampling clocks by  
varying the length of silent periods, which it can't do if silence  
suppression is disabled).

Colin




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