Sorry, but your fix is not good enough.
You will need to go back to your original uncompressed material and start anew.
You need to double the video size first, going from 256x224 to 512x448. This is done by doubling pixels, not stretching!
The best and easiest way is to add a single line in the AviSynth script that you have probably already made to include our signature.
Please refer
to this FAQ, and look for the word
pointresize.
Second, you need to crop black borders by adding a
crop line to the AviSynth script.
We don't have a specific FAQ for that yet, but the MeGUI program has a nice feature that generates that line for you. Go to the
Tools / AVS Script Creator menu. Select your video file, select the
Crop option, then click
Auto Crop. After that, select the
Script tab and copy the
crop line you'll find there to your own AVS script.
Check the result before going any further. Make sure the black borders have disappeared and that no actual part of the video was lost in the process.
And that's it. Encode the AVS script (using a better quality setting than last time) and you should get a video file that is almost pixel perfect, for a file size that should be a lot smaller too (like half your original size or something).
Please, if you have any more questions, make sure to join us on our IRC channel. Use
the FAQ to do that if necessary.