VirtualDubMod and Xvid File size problem

[jpc82]

I'm trying to convert some Mpeg-1 files to Xvid, and for some reason when i try to do it I get a Xvid file of the same size as the original Mpeg one.


This is what I do.

I open the Mpeg file with VirtualDubMod, select Fast Recompresion, and then Select Compression. From there I select Xvid and hit config. I then select 2pass - 1st pass, and hit ok. I press F7 set the name of the file as Dark.avi and set process latter.

It then returns me to the main screen. I go back to the compression tab, hit config on Xvid again, and then select 2 pass - 2nd pass, select the file size to 150000, and hit ok. After I press F7 again and save the file as Dark.avi

Then I bring up the job control window and hit start. When it finishes I am left with 2 files, video.pass, and Dark.avi. Problem is Dark.avi is 350214, which is a lot bigger then what I wanted.

What am I doing wrong I tried following tutorials but I can't find my mistake?

I have even tried having the avi from the first pass called a different name, but all that did was leave me with 2 over sized files and the video.pass

[junkmalle]

I have found that Xvid sometimes gets stuck and produces a fixed file size regardless of what you ask for. The only solution I've found so far is to uninstall the codec and reinstall it.

The other thing you can do if you don't care about the exact file size is to use Quantization mode. This is a single pass, constant quality setting. It can deliver just as good picture quality as 2 pass VBR but it only requires one pass. The problem is you don't know exactly what size the final file will be.

The Quantization value determines the quality. A low value gives high quality but large files, a high value gives low quality and small file size. The range is 1 to 31. I usually use a value around 3. At 2 the result is pretty much indistinguishable from the source. At 3 you can see a little macroblocking if you zoom in on still frames, but at full speed you don't notice them. At 4 you can see a little macroblocking on normal playback if you look closely.

I usually work with 640x480, 23.976 fps video. At Q=3 the average bitrate turns out anywhere from about 700 kbps to 3000 kbps depending on the material.

[jpc82]

I tried it with single pass and different quantization factors, and it does make a difference in size. However, the outputed avi is larger then the mpeg-1 file, and the quality is less.

I thought that Xvid was better compresion then Mpeg, and it would reduce the size.

Original Mpeg is 196,343, and the AVI is 239,446 with factor of 6. If I use a lower factor the files just get even bigger.

[jpc82]

I just looked at the properties of the files and I think I know what the problem is. I think it may have used PCM for the audio, and not the mpeg audio that was orignally there.

I guess I will have to play around with it a bit more.

[jpc82]

I just noticed that with 2pass it was also using PCM audio which was making the files huge.


I have now tried it with LAME MP3 and the files are much smaller now

[junkmalle]

Glad to hear you got it sorted out.