Quality conversion issue

[rcjhood]

I'm converting a raw avi file I captured with Fraps into mp4. I'm using MeGUI with this tutorial and it works fine except for some strange distortion every once in a while. It's not pixelation and I don't know how to explain it so you can see for yourself here. It happens at 0:17, 0:48, and 1:13. It doesn't matter what encoding setting I use, it always occurs, though not at the same place in the video. It does it when I convert to mkv also. I'm running WinXP on an e8400 dual core (and an ATI 4890 if it matters). I haven't tried converting with another program except Virtualdub which won't save in an mp4 package. Thanks for any help.

[Baldrick]

Have you checked the source so it looks fine?

Or else you could try another h264 mp4 encoder like handbrake or staxrip or xvid4psp and see how it looks.

[creamyhorror]

That's a nice basic tutorial.

Anyway, the problem looks a bit like weightp distortion. If you uploaded the encode directly to Youtube, then maybe Youtube's decoder is at fault. (It might be weightp noncompliant...)

To test this: In MeGUI, in the video section, next to the Encoder settings box, click the Config button. In the box that pops up, look for P-frame Weighted Prediction and change it to Disabled. Click OK and do the encode as per normal. Then try uploading the file to Youtube again, and see if the problem still occurs.

[rcjhood]

Yes, the source is fine. And it's not Youtube's fault - the issue is present before I upload.

I tried disabling P-frame Weighted Prediction and it didn't work. Any other suggestions? For now I'll just keep messing with it and also try the other encoders Baldrick listed.

Here's a newer one with P-frame Weighted Prediction disabled. This time the distortion happens really bad at 0:24.

[poisondeathray]

What x264 version are you using? If not r1471 as of today, you should update. There was a bug in an older build a while back that looked like this

Is your system overclocked? If so revert to stock settings temporarily and try another encode

Check memory integrity with memtest 86+ , I've seen this type of error with a bad memory stick

[rcjhood]

I should have considered my overclocked processor at the start. I reverted to stock settings and it worked. Noob mistake I guess. Thanks for helping everyone.

FYI I was using x264vfw version r1195bm so I updated to 1471 CLI before I changed the CPU clock. It didn't help but it still may have been an issue along with the overclock. Memory checked out fine.