rtp and ptime

[Sebastian Dröge]

On Mi, 2015-12-23 at 07:59 -0800, symeon.mattes wrote:
> Hi,
> 
> I have tried the following:
> 
> GstElement * rtppcmapay;
>     rtppcmapay = gst_element_factory_make("rtppcmapay",NULL);
>    
> g_object_set(G_OBJECT(rtppcmapay),"min-ptime",2000000,"max-
> ptime",20000000,NULL);
> 
> 
> but it didn't work. Without setting the min-ptime and max-ptime I had
> ptime at 10ms and by setting setting them with g_object_set I had
> something around 170ms. By changing the value 20000000 to something
> else e.g. 20000 the ptime in wireshark didn't change to less than
> 170ms. I suppose the min-time is in nsec? Do I need to change
> anything else?

It's in nanoseconds, yes. But you can only change it up to the value of
the MTU, not higher. Running this pipeline here with values between
10ms and e.g. 170ms shows the difference in output packet sizes:

gst-launch-1.0 audiotestsrc ! alawenc ! \
  rtppcmapay min-ptime=170000000 max-ptime=170000000 ! \
  fakesink silent=false -v

For stereo, of course only half the maximum ptime is possible with the
same MTU.

-- 
Sebastian Dröge, Centricular Ltd · http://www.centricular.com

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