Blocks in frames using QuENC for MPEG2 downsizing

[itabb]

I recorded a TV show on a DVD standalone burner in SP format 5kbits/s, 720/480. I want to downsize these to LP format 3kbits/s, 352/480, to fit more on a DVD because SP and LP look the same. I use DGIndex, AVISynth, and QuEnc (per the guide) to do this. I use 2pass, no scene detect, high quality, no trellis, no matrix, no extreme. Most of the frames turn out great. However, every 12 or 15 frames, even the I frames, will be super blocky. The rest are perfect. What settings do I have wrong?

I attached an image. The previous frame, 559, a p-frame, is normal.

This, and the next few frames, is the problem after QuEnc encoding.



This is the previous frame, a p-frame, again, after the QuEnc encoding. This one is OK.



Finally, this image is a b-frame, number 560, from the original file created by the DVD Recorder in 720x480 5kbits/sec



It seems like I should just use the hardware encoder to change format (dvd reader connected via RCA cables to the DVD Burner) instead of using software encoding.

[jagabo]

Did you change something between the first and second pass?

[itabb]

But if I record the same show in LP mode (3000 bits/s and 352x480) from the TV, it is not this blocky. The intros are the same on this show, I'll have to get an image. I just have to think I've got the wrong settings or the wrong tool. Or, it could be because I'm encoding down from SP, so errors are magnified.

Would I do better if I transcoded via Nero Recode 2?

[itabb]

I am not sure if this makes a different, but I am following the guide that uses Avisynth and DGIndex. It's the first guide listed with the tool.

Also, I get the same terrible results even when I re-encode from 9000 kbits 720x480 to 5000 kbits 720x480.

[jagabo]

I've only played with QuEnc a bit, but I got rather poor results when using it. TMPGEnc Plus does better.