[vlc-devel] vlc skipping frames - looks very vlc related

Marius Kjeldahl marius at kjeldahl.net
Fri Nov 26 15:00:40 CET 2004

I'm having trouble with vlc skipping frames for certain streams. This is 
probably related to either the amount of data in the stream and/or 
format of the stream. For reference, I've captured a stream that 
demonstrate the problem and tested it on at least one other player.

When I run the captured stream in vlc, there are noticeable jumps which 
is probably the result of vlc skipping frames (the message window 
messages about frames skipped seems to coincide nicely with the jumps in 
the video).

When I run the same stream on the same hardware using mplayer, I get no 
messages about skipped frames and the visual defects do not seem to 
appear either.

The stream in question seems to be variable rate with a very high peak 
bit rate, but the problem seem to appear on both the very different 
machines I've tried it on (Windows, one AMD64 3200+ and one Mobile 
Pentium 4 1.8MHz). On the same hardware, mplayer has no problems. I also 
ran the same stream under vlc on linux (version 0.8), with no visible 
improvements (still skipping, although in different places).

AFAIK, mplayer uses libmpeg2 (that's what is says when playing the 
stream), and I've tried forcing vlc to use it also, but I can see no 
improvement in the vlc output, so I'm guessing the mpeg decoding is not 
to blame (ignoring the issue of possible different versions of libmpeg2 
for now).

I've put up a copy of the stream on:


if anybody would like to take a look at it. Please let me know if you 
figure out anything interesting.


Marius Kjeldahl
(Running on AMD64 3200+, Intel Pentium Mobile 4 1.8MHz, Windows XP Pro, 
Gentoo Linux x86, vlc 0.8.1 rev. 9409).

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