Multiplexing WinTV PVR captured MPEG

[Shuggie]

OK this may be long - so I apologise upfront.

Also I'm sorry if this is the wrong forum - I wasn't sure between Capturing and Conversion.

Here's the thing. I know that when I capture an SVCD MPEG with my Hauppage WinTV PVR card, I have to multiplex it or the audio's all out of sync. But I don't really understand why. My simplistic understanding of multiplexing is "joining a video stream with an audio stream" but the file's already got both audio and video so what's the deal?

Baldrick - if you're listening - you wrote the howto on that - do you know why the multiplexing is necessary? What it does?

Now you'll probably be wondering "why do you care so long as it works?"
Good point - except sometimes it doesn't. Sometimes TMPGenc throws an error about there being something wrong with the audio stream. Occasionally - especially before I got the latest drivers - there's an audible glitch in the sound - but lately I can't hear it.

Now I have a number of tools which I can use to split the audio and re-encode - so I was thinking if I understood what multiplexing is doing I could find another way to do it.

I've tried simply extracting the audio and multiplexing but it's still out of sync.

Another method I tried which almost worked was to treat the mpeg as if it was a VOB file and run through a DVD rip process using DVD2AVI then TMPGenc and joining a separate WAV file. This syncs the sound but it ends up all 'stuttery'.

Any help gratefully received.

Ta
:wink

[thxkid]

well I have the PVR and even if I don't demux the SVCD the audio is still in synch, what I come across if I don't demux the MPEG2 is that NERO will not see it as a correct SVCD, why you have to do it is beyond me, I have even used TMPGE to jut and join and it works great as long as you have not allready demuxed the MPEG2.
weird nut it works.

[Shuggie]

I've discovered the errors I'm getting are buffer underruns. So I'm going to try demuxing and then re-mux with bbmpeg - which is recommended for this kind of problem.

But I'd still like to know what multiplexing is all about.

[Shuggie]

Well after a lot of experimentation I've found a method that works.

- use graphedit to split a wav file off the mpeg.

- load the mpeg into DVD2AVI and save as project (not AVI)

- encode in TMPGenc with an SVCD template, the d2v file as the video
source and the wav as the audio source. I'm using tooLame but I
don't think that's essential.

Of course this takes a lot longer than a simple multiplex as it is effectively a full re-encode.

Hope this helps someone else