[Ffmpeg-devel] Bug in ASF mux? (was: RE: [Ffmpeg-user] reduce the time delay)

Michael Niedermayer michaelni
Tue May 24 14:24:31 CEST 2005


On Tuesday 19 April 2005 03:06, Dario Andrade wrote:
> > > Widows Media Player is delayed 3 seconds. How can I further reduce the
> >
> > time
> >
> > > delay. The movie is distribued within LAN, so I do not care the
> > > bitrate. Please help me. Thank you!
> >
> > The Windows Media client adds a delay to allow for buffering. The delay
> > is configurable within the client settings, but there will always be some
> > delay due to encoding, propagation and stream setup delay. Different
> > clients watching the same "Live" stream will often exhibit different
> > delays.
> >
> > Ian Grush
> I have noticed that the ASF multiplexer in ffmpeg is not really optmized
> according to specs. There is something related to preroll header field, and
> timestamps.
> A normal ASF file (there a really nice utility called Windows Media ASF
> Viewer,
> http://www.microsoft.com/windows/windowsmedia/format/ASFViewer.aspx, that
> may be used to examine the ASF file further) has a preroll equal to the
> buffer window (normally 3 or 5 secs), and timestamps (actually packet send
> times) beginning exactly at the specified preroll (from the header field).
> >From the files generated by ffmpeg, I could see there are some glitches
> (such as local playback delay in the windows media player, not the one
> created by the network buffering, etc...). Is anyone willing to fix it?

well, as you can see from the lack of a fix, the awnser seems to be no
you can fix it yourself and send a patch if you wish


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