DivX 5.0.1 and Artifacts

[Stormblade]

Hi all,

Ok, I'm converting from an mpeg-1 to DivX 5.0.1. My settings were set according to this article here:

http://www.divx-digest.com/articles/divx5_setup.html

My problem is this. When I choose 2-pass encoding (Either 1st pass or 2nd pass) in Virtual Dub the resulting file has artifacts during playback.

And once when I'd forgotten to disable the Quarter Pixel option the file produced caused both Windows Media Player 8 and DivX Player 2.0 to crash.

The only way I was able to get a decent output was to use either 1-pass or 1-pass quality based but according to that article this is crappy compression.

Anyone know what I'm doing wrong? Should I stick to the 1-pass ones? Perhaps just 1-pass and play around with bitrate? Or just 1-pass quality based which produced a file smaller than the original with not too much quality loss.

My system specs are in my signature. Click on the link

[techno]

keep experimenting.

but if u want quality and low file size, use DIVX 3.11alpha

https://www.technosoft2000.co.uk/divx

Techno

[Stormblade]

Ahh. Well that would explain it. I was told that the 1-pass option for DivX 5.0.1 was the equivalent of the 3.11 Alpha and it seems as so. I just re-compressed a 218 meg mpeg to 78 megs using DivX 5.0.1 with 1-pass quality based option. And it looks good.

I still would like to know why using the 2-pass resulted in artifacts though but for now 1-pass and 1-pass (quality based) works for me.

[khp]

Originally posted by Stormblade
I still would like to know why using the 2-pass resulted in artifacts though but for now 1-pass and 1-pass (quality based) works for me.

Just a thought (and this is ofcause wild speculation on my part).

Did you use the mv log file ?, for the 2-pass encoding.
If you have artifact that only showup with 2-pass encoding, with all other things beeing equal, I think the only obivous culprit would be the mv log file.

Could you perhaps retry the 2-pass encode without using the mv logfile ?.

[Stormblade]

Yup that was it. Soon as I unchecked the use MV File it no longer produced artifacts. I don't remember checking this option and I sure don't know what it is nor what it does but thanks much. I'll have to try using 2-pass now and see if I get better compression with same quality as I was getting with 1-pass

[khp]

The MV file logs motion vectors, the divx codec use motion vectors to improve the encodeing of objects that move, by only encoding the object once and then haveing a motionvector, specifying how much an object should be moved at each frame.

Using the MV logfile means that the motion vectors found durring the first pass will be reused in the second pass. This means that the codec don't have to do motion search, durring the second pass, which speed up the encoding.

If you can reproduce this problem, you should definetly report it to DXN. From what I can see this is not on the official known bugs list.

http://www.divx.com/support/divx/divx_knownissues.php