Hello David, Yes, I'm digging up this issue, yet again. :)
> I should probably also point out that while this may help your problem, > it won't completely solve it because it is only one piece of the puzzle. > The timer inaccuracy results in extra conference latency over time, but > the other problem is that delays in scheduling the Asterisk process can > cause big and sudden jumps in latency that this new ztdummy.c won't fix. > The real problem is that Asterisk allows voice packets to back up in > its input queue, and that has an unbounded queue depth. > Attached is a patch to Asterisk's channel.c that limits the queue > depth of voice frames to a maximum of just 2 frames (40ms) on the channel > input queue. Under certain circumstances, this may result in an occasional > dropped voice frame, but that is better in my opinion than adding extra > latency to the call. Some reports of audio quality problems coming in from the AskoziaPBX community seem to incriminate this patch. When this occurs on IAX channels, enabling / increasing the jitterbuffer seems to help which leads me to a dropped frame issue. This makes sense as these systems are usually low-power embedded or SBC systems. Removing this patch from my build process should take care of the problem but I really like the idea of such a patch providing tangible feedback when the system's limits have been exceeded instead of merely increasing delay infinitely. My question, do you have a recommended higher value for this queue limit? I was thinking of setting it to 5 frames. This would be roughly 100ms which, in a round-trip situation would lead to a maximum of 200ms of delay being contributed to the call. This is, as I understand it, the theoretical limit in delay that a call can have before its participants are unable to coordinate their conversation. Thoughts? Once again, thanks for contributing and providing insight into these issues! Regards, -Michael _______________________________________________ --Bandwidth and Colocation Provided by http://www.api-digital.com-- Asterisk-BSD mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-bsd
