Best Way To Convert a 320x240 Low Bitrate DivX to VCD
If you use IRC or Usenet then you are familiar with 320x240 DivX files that are common for TV episode captures (such as the new Survivor episodes from Australia and the UK and IRC episodes of Friends as examples).
The one thing these episodes have in common are that they 1) are low bitrate 2) are a non-standard resolution .... my guide here is directed at these type of files to help you make a watchable VCD.
First thing to do is run the files through DivFix (this is a precaution because a lot of these files are downloaded with 'resume' so to prevent 'stream writing errors' we rebuild the index with DivFix)
Now open the file in VirtualDub and extract the audio. Go under Audio and select "Full Processing Mode"
and then do File-Save WAV ... select the location you want to save the wav file and hit save. I usually use the same name of the DivX file and just add .wav to the end (example: SurvivorUK2_Ep09.wav)
Find The Frame Rate
in VirtualDub go to File-File Information and look for the fps (so we will know what TMPGEnc Template to use.
Converting:
We will convert the DivX in TMPGEnc.
Open TMPGEnc - hit load and select the correct VCD template
if it's an odd frame rate as some DivX files are - 15fps for example - select NTSCFilm and let TMPGEnc convert the fps automatically
In my example the source is 25fps so I am using VideoCD(PAL) -- put the original DivX in as the Video and your exported WAV file as the Audio Source
Now for the important part - hit settings on TMPGEnc and select the Advanced tab -- set the Video Arrange Method to Center (Keep Aspect Ratio) and make sure your Source Aspect Ratio is 1:1
[what we are doing here is telling TMPGEnc to leave the resolution as it is but create an output with borders --- this reduces the amount of macro blocks created by MPEG encoding since TMPGEnc does not have to resize the source -- with these type of low bitrate source files resizing them to fit 352x240 or 352x288 creates a lot of problems and reduces the overall quality of the final MPEG]
In my example the result will be a 352x288 VCD with the 320x240 source preserved - it will leave some black borders when you play it back on your DVD but the results are much better than using Full Screen (Keep Aspect Ratio) as your Video Arrange Method.
Example Results:
320x240 source : 352x288 output
Improve the results even more:
You can improve the results even more by using the Noise Reduction Filter in TMPGEnc -- I find that with these low bitrate files the best setting is Still Picture 55 (up to 75), Range 2 and Time Axis 6 (up to 12) ... I don't usually do this because it add so much more time to the converting process but those of you with faster machines might want to do this.
You can also go into the Quantize Matrix tab and select Soften Block Noise to 100 (on both intra and non-intra block noise) -- this helps but it's subtle
