[Live-devel] QTKit QTCaptureSession as a DeviceSource

[Austin Snow]

There is not any large delay (~5 to 10ms) from the call to downstream  
call to doGetNextFrame() and the upstream call to   
FrameSource::afterGetting(this) in DeviceSource.cpp.

from downstream call to doGetNextFrame()
fPresentationTime.tv_sec=1230780299
fPresentationTime.tv_usec=377538

from upstream call to  FrameSource::afterGetting(this)
PresentationTime.tv_sec=1230780299
fPresentationTime.tv_usec=381672

next downstream call to doGetNextFrame()
fPresentationTime.tv_sec=1230780301
fPresentationTime.tv_usec=46294

sometimes to less then a 1 and sometimes its more as high as 3 sec.

The delay is waiting for   if (!isCurrentlyAwaitingData()) return; //  
we're not ready for the data yet
  to NOT return.

Also, I'm setting the presentation time, no change.

Could it have something to do with the passing of the data to the  
encapsulation for the ip packets?  There is not much multicast traffic  
being sent.

Thanks again.


On Dec 31, 2008, at 9:59 PM, Ross Finlayson wrote:

>> dura is set for each call, 33366 for 30 frames per sec or 66666 for  
>> 15 frames per sec, still the data is called for ~ every 1.
>>
>> modulo_time_base=0x00
>> fNumVTIRBits=0x00
>> vop_time_increment=0x00
>>
>> The above are always zero, could this be the problem?
>
> No, I don't think so.
>
>>
>> Also I'm not setting the presentation time, what format should it  
>> be in or is it not needed?
>
> Yes, you need to set "fPresentationTime"; the best way to do this is  
> to set it to the result of calling "gettimeofday()" each time.  
> However, that's probably not the cause of your problem.
>
> Sorry, but I don't know what's causing the delay that you're seeing.  
> Are you *sure* that there is a ~1 second delay between each call to  
> "FramedSource::afterGetting()" and the *next* call to  
> "doGetNextFrame()"?
> -- 
>
> Ross Finlayson
> Live Networks, Inc.
> http://www.live555.com/
> _______________________________________________
> live-devel mailing list
> live-devel at lists.live555.com
> http://lists.live555.com/mailman/listinfo/live-devel

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