[MPlayer-users] Re: status of the rtsp support NOVIRUS

[Luca Abeni]

Hi Ross,

thanks for the answer!

[...]
> >I am still trying to investigate the problem, but it seems that the
> >mplayer RTP demuxer starts to discard packets because the difference
> >between audio and video timestamps is too big...
> >
> >Is this a known issue?
> 
> Yes - but it's a *feature*, not a bug.  It's how the RTP demuxer helps 
> bring audio and video into sync (complementing the a/v sync mechanism used 
> by the general MPlayer code).
Sorry... I was not clear in my description of the problem... What I
wanted to say is that rtp_demux.cpp starts to discards packets and never
ends to discard them. In other words, it never exit from that while()
cycle.

This seems to be due to the fact that at some point mplayer sees an A-V
skew of something like 1000s or more... Maybe mplayer will stop to
discard packets after more than 1000s ;)

In my understanding, this seems to be due to the fact that mplayer
starts to use the audio and video packets when they are not
synchronized... Hence, as soon as the first RTCP packet arrives one of
the two streams synchronizes and its timestamps "jumps" to a completely
unrelated value. At this point the difference between audio timestamps
and video timestamps is very large and mplayer starts to discard
packets. At least, this is my understanding: maybe it is completely
wrong...

I am trying to verify my theory by adding code that discards packets
until audio and video are synchronized. I'll send another mail later to
say if it worked.

> >If someone was able to correctly receive an MP2 via rtsp, can he
> >describe his setup?
> 
> Your 'setup' looks correct, but please make sure that you're using a recent 
> version (2003.09.11 or later) of the "LIVE.COM Streaming Media" code, 
> especially for building "vobStreamer".  (Earlier versions of the code 
> contained a bug that could cause problems streaming MPEG-2 video.)
Yes, I got the latest snapshot from the live.com site.

> Also, make sure that your LAN is fast enough for MPEG-2 streaming.  A 10 
> Mbps Ethernet may not always be fast enough; I recommend 100 Mbps.
It is a 100Mbps ethernet... I don't know about MPEG-2 streaming, but I
know that it is enough for MP4, because I was able to succesfully
receive MP4 streams with the MP4IP client (mplayer + live.com failed, as
for MP2).

				Thanks,
					Luca
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