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Re: buffering time

At 2:02 PM +0200 7/23/01, Francisco Javier Cabello wrote: 
Hello,

I posted a message about this issue long time ago, and nobody replied me with
a solution.

Can anybody confirm that is 'impossible' to reduce 3 seconds buffer when your
are receiving RTSP/RTP video with QuickTime 5?

This is important for my job and I won't lost more time researching about
that. Thanks.


It is possible to reduce it if you code your own playback application with QT.

Fixed shortdelay = 1<<16;
QTSPresSetInfo(myPres,kQTSAllStreams,kQTSTargetBufferDuration,&shortdelay);

The thing is, it may not work well, which is why we pin to a minimum of 3 seconds when reading an SDP file. QT Streaming was not optimised for video conferencing.

What it comes down to is whether 'low latency' is a design goal or not. For video conferencing or IP telephony it is, so all the codecs and packetizers are designed with that in mind.

QT Streaming deliberately relaxed this constrain so we could work with a wider range of codecs in both the video and audio domains, and use packets with a longer duration to reduce per-packet overhead (particularly important for low-bitrate streams, modems etc.).

In order to tolerate this variability, cope with network jitter, and retain good synchronisation between streams with different latencies, we need a larger buffer delay.

References: 
 >buffering time (From: Francisco Javier Cabello <email@hidden>)



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