XMS888 - Problem with Sound on XVID

[mooball1]

I've recently been trying to get some videos working that have the following encoding:

XviD MPEG-4 codec 1039kbps
mp3 48000hz stereo 127kbps (vbr?)

The problem is that when these videos play, they tend to skip at certain points in the movie, regardless of how many times I play them or try burning them again. Always the same spot. In the end, I tried fiddling around with some different audio codecs and determined that with no sound encoded in the vids, they worked perfectly. So it had to be audio, I thought. So I tried decoding one of the vids with no compression at all and then re encoded it in virtual dub into mp3 format. That seemed to work... on the first vid atleast. The others still skip and jump, but nowhere near as much as they originally did.

So it would appear that I'm doing something wrong in virtual dub with the sound compression. Any suggestions here? I think I've been through about 50 blank cds testing all this out and I've really not gotten to close to solving the prob.

As a bit of background info, I get this message when opening the source file in virtualdub:

VirtualDub has detected an improper VBR audio encoding in the source AVI file (audio stream1). The current preference is to re-write the audio header with standard CBR values during processing for better compatibility. This may introduce up to 2085ms of skew from the video stream. If this is unacceptable, decompressed the entire audio stream to an uncompressed WAV file and recompress with a constant bit rate encoder. (bitrate: 126.8 +- 10.3kbps). Do you still want to rewrite the header? YES or NO.

[andw]

Definitley better with CBR audio.
Buy one or two CDRW's, for testing, otherwise you waste a lot of cd's.
As it says, dumping the audio to a WAV file, then re-encoding with constant bit rate is the best way to go.
I've never had the problem you've described, but have had audio get out of synch with VBR.

[mooball1]

OK, so how do I do this in virtualdub? Just set the audio output to no compression and then recompress in mp3 format? In virtual dub, it only allows me to encode mp3 at 56kbps max! Any help there? Thanks for the suggestions!

[bwg]

OK, so how do I do this in virtualdub? Just set the audio output to no compression and then recompress in mp3 format? In virtual dub, it only allows me to encode mp3 at 56kbps max! Any help there? Thanks for the suggestions!
Ahhh yes...the ever frustrating VBR re-encoding problems. I embrace it like an old friend :p
It's bloody annoying, trust me, I've been there. Firstly, you need to get your hands on an mp3 codec (the reason you can only go to 56kbps is probably that you have not installed a 3rd party mp3 codec yet). I've always had success with the radium codec, get it here (http://www.riphelp.com/downloads/radium_codec.html).

EDIT: ooops, looks like those links are no longer available, as is the radium codec itself. Shows how long it is since I've tried up-grading :) The pick of the bunch seems to be lame, which you can download from here (http://www.free-codecs.com/download/Lame_Encoder.htm). Just unpack it and right click on the "LameACM.inf" file and select "install" from the menu. This will add the .dll to your system folder and a line or two to your registry (don't expect any install options or prompts).

As andw said, you need to convert the mp3 audio to a wav file. In virtualdub, the easiest way to do this is by selecting "save WAV..." in the file menu, it will ask you to specify a file name. Once it has saved the audio as a separate WAV file, which should be relatively large, you can then select "direct stream copy" for the video, and under the audio menu select "WAV audio...", where you will be asked to choose your WAV file (the one you just created). In the audio menu again, select "full processing mode", then select compression. Select one of the mp3 codecs from the list (one of them will be your old default one, the other will be the Radium or whichever other codec you chose to install, eg Lame MP3). There should be a greater range of bitrate options to choose from now. Then just "save as avi"!

Hope this helps :)

[mooball1]

Thanks to all concerned. Bought myself some cdrws and followed the instructions above. Seems to work perfectly! Cheers.

[Scaramouche]

Ah yes.. VBR MP3 = Guaranteed to cause Sync problems. Stay away from it if you can.

Personally i ONLY use AC3 as I have a nice Harman Kardon amplifier. For directors comentary I re-encode to 96 k/bits Mono (centre speaker only) AC3. its about the same size as a 128 k/bit VBR MP3