xvid brightness issue

[dukey]

not sure if this is the correct forum to put this in.. anyways

I notice the brightness between encoding xvid/x264 and the source is different. When encoding x264 the brightness comes out the same as the source. When encoding xvid the brightness is always brighter.

I am using exactly the same avisynth script to test the 2, just different encoder. Same player to decode, media player classic using VRM9 renderer.

If I do this ..

ColorYUV(levels="TV->PC")
in my avisynth script.

If i preview this script in mpc .. the brightness looks too dark. But by the time I have encoded the video (with xvid), the brightness has been corrected to normal.

Any idea whats going on ?

The rest of my avisynth script is just this
loadplugin("C:\Program Files\AviSynth 2.5\plugins\DGAVCDecode.dll")
AVCSource("C:\Recordings\k.dga")

heres a link to screenshot comparison. Xvid is on the left. X264 is on the right .. The x264 encode is the closet to the source. Xvid one is too bright.
http://img64.imageshack.us/img64/186/comparisoncu5.jpg

[sysKin]

What Xvid decoder do you use? Most (including xvid itself) have brightness slider.

[Dark Shikari]

Could that be an issue of PC -> TV luma conversion?

[Didée]

The encoder has nothing to do with this. Be assured that encoders like Xvid or x.264 don't change the brightness of their input at all.
It's merely a decoding issue, namely which video renderer is used when building the playback filterchain: Overlay mixer, VMR7, VMR9 windowed, VMR9 renderless, whatnotelse ...

[dukey]

I've tried decoding with xvid, divx and ffdshow
all give identical results

Hmm .. but
the overlay mixer in media player classic and VMR7/9 give different brightnesses. Overlay seems to be giving the correct brightness, VRM7 and 9 seem to be using 'TV scale' brightness. The only trouble is, overlay mixer doesn't really work at all in Vista, if you go fullscreen it all goes garbled.

[foxyshadis]

Set the decoder to output RGB. Or, if using ffdshow, you can do it with levels, but HQ RGB isn't a bad idea in any case, reds will look a lot nicer.

[Blue_MiSfit]

I used to always do HQ RGB conversion, and really liked the results, especially in the reds. But I've found it to be very slow sometimes. Is this expected?

You might want to try using the patched media player classic builds that have EVR support. Should work a lot better with vista.

It worked for me on XP (when I installed .Net 3.0), but had other bugs so I decided against it and use a standard build.

~MiSfit

[dukey]

I found Haali's video renderer gives the correct brightness
and works on vista too :]