[vlc-devel] RTP jitter buffer does not work

Marian Ďurkovič md at bts.sk
Mon Sep 7 12:02:39 CEST 2009


   during testing of some RTP jitter buffer properties it turned out
that it doesn't work if the jitter value grows to > 5 msec. If this
happens, RTP input completely stops feeding packets to the demux.

   Closer investigation shows, that arrival of next packet updates
src->last_tx with more recent timestamp, and deadline gets recomputed
again based on this updated info. As a result, the deadline is always
+5 msec in the future and never expires.

  On the other hand, the jitter value on an otherwise idle LAN gets
as low as 0.2 msec, which is *way* too low to be of any use for reordering
purposes. In 0.8.6 we had 100 msec reordering buffer by default... This
probably isn't needed today, but something like 10 - 20 msec should be
the absolute minimum IMHO.

        With kind regards,


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