Image quality and directshow

[Daodan]

While closely analizing some x264 encoded samples (from the SSIM tests you can find in a thread below) I used VDM to save pictures from the samples (directshowsource). What surprised me is that the image quality in VDM is much better than the one in mpc. I tried all the possible outputs in mpc (I usually use overlay mixer) but the problem remained. The picture problem I'm talking about I think is called 'banding' (color gradients not looking smooth) and this is one of the problems I alwasys found anoying about h264 when not using high enuogh bitrates especially.
So my question is why? And especially, how can I make look the same in mpc? (by the way, I use Haali splitter and CoreAVC).

[foxyshadis]

In ffdshow, try using "high quality yv12 to rgb conversion" or whatever it's called, unless you already did. Not quite sure how you get to it through mpc's config. Otherwise it could by low frequencies getting quantized to death, like xvid tends to, which a custom matrix would help out on. Still, I suspect it has to do with vdubmod using a better yv12->rgb converter than directshow.

[Oline 61]

But ideally there wouldn't be a conversion would there? I know my 6600GT uses a YV12 overlay, which is what the encoded x264 video is, so there should be no conversion on playback.

[Soulhunter]

Im also a "proud" GF6600GT owner... (http://forum.doom9.org/showthread.php?t=106111) :\


Bye

[Oline 61]

Wow, I had no idea about any of that, thanks Soulhunter. So all I need to do is check off the high quality conversion in FFDShow?

[Soulhunter]

@ Oline 61

Only if you dont care about crappy upsampled chroma...


Bye

[Oline 61]

I don't believe I entirely understand the settings required for chroma upsampling with overlay and high quality YV12 to RGB conversion. Media Player Classic is set to use overlay. Here is my FFDShow config: http://img295.imageshack.us/img295/1682/untitled1gc.jpg
What do I need to change?

Thanks for your help.

[Soulhunter]

You need to uncheck YV12, otherwise RGB32 isnt used...


Bye

[Daodan]

Thanks for the replies guys. I'm also a proud owner of 6600GT but it seems that doesn't help. I will try that ffdshow thing as soon as I get home. And how should upsampled chroma look like? (to see what I'm missing).

[foxyshadis]

http://forum.doom9.org/showthread.php?t=107910

Check out my first pics vs Soulhunter's, that's the difference, if a bit exaggerated compared to normal sources. The ultraclean and sharp cg-animation makes it stand out a lot more than you'd probably see.

[Soulhunter]

And how should upsampled chroma look like?

RGB Source -> YV12 bad upsampled -> YV12 proper upsampled (http://img7.imageshack.us/img7/3314/chrupsampling4vf.jpg)


Bye

[Daodan]

Thanks. From what it looks to me I think this is less likely to be observed in a movie than that anoying banding.

[Soulhunter]

Well, with a fast CPU you can do both in realtime! YV12 Input -> FFDShow-> Some DeBand processing (AviSynth section) -> HQ YV12 to RGB32 conversion (output section) -> Overlay mode...


Bye