Re: WMF Demux causes glitches in audio playback

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On 28 Juli, 16:22, Geraint Davies <gerai...@xxxxxxxxxx> wrote:
On Thu, 23 Jul 2009 11:01:07 -0700 (PDT), Daniel S <sum...@xxxxxxxxx>
wrote:





Hi!

I have used the ASF/WMV-mux (http://www.riseoftheants.com/mmx/faq.htm)
to generate an ASF audio file with a mp3 compressed audio stream.

[mic]->[MP3 compressor]->[ASF-mux]

If I replay the resulting file with the stock ASF reader it works fine
and I hear good quality audio. However, if I use the WMV demux from
http://www.gdcl.co.uk/downloads.htmI get glitches in the audio
playback. If I look at the timestamps on the samples sent from the
output pin I see that they are not a continues stream. I don't really
know where to start looking for problems... I have tried to fix the
timestamps or set timestamps to zero but it doesn't give me any
different results. Is it the non-continues timestamps that are causing
the glitches?

What should I try next?

The reason I want to the the WMV demux is that I want to be able to
set the play rate of my graph.

Any ideas appreciated...

/Daniel

I'm sure I've heard of this before. I checked my version history and
there was a change back in 2007 which was related to this. I think it
is related to the fact that the timestamps at capture probably do not
quite match the declared frame rate. This is handled inside the WMF
sdk, but if you separate the demux phase from the decoder, some
information is lost.

Assuming that you are running the most recent version of the demux,
perhaps you could send me a sample file to investigate?

G

I downloaded the mux from your web site just a couple of days ago so
it should be the latest version.

However, I have now found out that the asf mux seems to drop frames
sometimes. This is causing the glitches in the replay. However, since
the stock ASF plays the file ok there might be something your demux
could do as well...

I will send the file to your e-mail address. Send me a mail or post a
reply here if you somehow don't receive it.

/Daniel
.

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