Need to re-encode XviD files to remove Custom MPEG

[getajob]

Problem: I have several files that use a MPEG Custom quantization matrix. These files will not play in my set-top MPEG4 DVD player which only supports H.263 or MPEG quantization (Player has a ESS Vibrato chip).

Symptoms: These files crash VirtualDub with "divide by zero" or "error code -100" error messages - depending on the version.

They also crash Windows Media Player.

VideoLAN's vlc Media Player handles them fine and produces excellent results.

Question: How can I re-encode these files so that they use either H.263 or MPEG quantisation?

[RabidDog]

dr divx?....

[BJ_M]

going to kill quality doing so though ..

plus i use all sorts of custom quantization matrixs including all 8's for high bit rate HD xvids and never had a problem with them in v-dub ..

[celtic_druid]

If VDub, wmp, etc. crash then presumably every other app that uses installed codecs/filters will crash to, including Dr.DivX.

I would suggest that you update XviD, ffdshow or whatever you are using for decoding, because as said a custom quant matrix should not cause crashes.

You could also use mencoder to re-encode, because like VLC it doesn't use installed decoders. Default matrix is h.263.

[BJ_M]

"Default matrix is h.263" <-- low bitrate

mpeg matrix <-- high bitrate



keep that in mind ..

[celtic_druid]

You sure? As far as I can tell mencoder always use h.263 if no matrix is specifed, no matter what the bitrate.

[getajob]

The good news is that mencoder improves things dramatically in that the resultant .avi file will play in my DVD MPEG4 player - however there are some serious a-v synch problems.

When I play the output in Windows Media Player (my computer equivalent of a basic player) the video halts and the audio plays fine.

When I play in the MPEG4 DVD player, the audio halts and the video plays fine.

VLC Player handles these fine as always.

Running it through Vdub again seems to improve things almost to an acceptable standard with WMP but I've run out of time to test a DVD.

Unfortunately mencoder is a bit daunting for the novice (lots of options).

Any idea why I would be getting a-v synch problems? I'm off to look for a guide for mencoder...

[BJ_M]

You sure? As far as I can tell mencoder always use h.263 if no matrix is specifed, no matter what the bitrate.

I am sure - 263 is designed for low bit rate ...


its optional, but quality will be much bettter using mpeg matrix's at high bit rates (sharper)

[celtic_druid]

That isn't what I was saying. What I said is that mencoder by default uses h.263, even if you encode at quant 1. To use MPEG you would have to quant_type=mpeg or whatever to the command line.

[getajob]

Thanks to everyone who offered help here but especially celtic_druid whose tips were spot on.

This problem was eventually solved but upgrading to XviD 1.0.3. Immediately after upgrading WMP would play these problem XviD files however Vdub still crashed the old messages.

It turned out that Vdub was still using the old xvid.dll file. By running some old XviD uninstall routines I had and re-installing XviD 1.0.3 I was able to persuade Vdub to use xvidvfw.dll instead.

Now I just have to learn the new XviD 1.0.3 interface...

[BJ_M]

That isn't what I was saying. What I said is that mencoder by default uses h.263, even if you encode at quant 1. To use MPEG you would have to quant_type=mpeg or whatever to the command line.

misunderstood -- sorry ..