bad quality with overflow changes

[renski]

Hi,

I've had a movie I've been trying to encode for a few days now... I've made some changes to my xvid settings for the undersized xvid as per this thread: http://forum.doom9.org/showthread.php?t=92046

However when I change the Overflow treatment to 20 20 20 I do get the right file size but the quality is shithouse. It's blurry on almost every frame, small glitches and the video seems to be flickering almost.. its asif the frames are going from clean to blurry back and forth.. and its in the entire movie. Is there anyway to fix this?

[foxyshadis]

Turn post-processing off on whatever you're using. That sounds like what happens when your b-frames are way too high of a quant. If you still want post-processing, tweak the b-frame ratio lower and put more weight on the offset.

If you opened the status window, that would show you exactly where they fell, otherwise you can use divx drf analyser to check for average b quants.

[renski]

i'm using gordianknot, where can i turn post processing off?

[jon.schaffer]

You first had an undersized file, right?
I advise you to keep the min quantizer to 2 and increase the resolution...
Or, at least (if you want to keep min quantizer = 1), try these quantizer settings: 0, 5, 10 instead of 20, 20, 20 (which are too agressive values). You should hit the correct file size without quality dropping.

[foxyshadis]

i'm using gordianknot, where can i turn post processing off?

It has nothing to do with the encoder, it's entirely a playback problem. So ffdshow, xvid, divx, what's playing the file. However, this may reveal that instead of pulsing blurriness, you end up with pulsing blocking instead, which is why I recommended changing the b-frame settings.