Colorspace Conversion Questions

[Cuttlefish]

I'm a complete newb when it comes to colorspaces, so answering any of the questions below would be of immense help to me.

1a) Is it true that ffdshow's raw video filters (more specifically the Resize & Aspect, Denoise3D, and Deband filters) only work in the YV12 colorspace? Or does it support YUY2 as well? Playing a video and then activating the EVR-CP stats page (shown by pressing Ctrl+J in MPC-BE/HC) shows that mixing is done in YUY2, but look at this:

The HQDN3D (aka Denoise3D) README page here ( http://akuvian.org/src/avisynth/hqdn3d/hqdn3d.txt ) says that the 0.11 version only works in YV12.

1b) What about the Avisynth filter? What colorspace does it work in?

2a) Does RGB Conversion in ffdshow happen before all the other filters or does it happen last?

2b) In the RGB Conversion menu, do the Dithering and "High-Quality YV12 to RGB Conversion" options only apply to YV12?

According to the documentation here: ( http://ffdshow-tryout.sourceforge.ne...version#method ), Dithering also works on YCbCr colorspaces. Does this mean that "High-Quality YV12 to RGB Conversion" works with YUV2? Note that the Dithering option can only be enabled when the "High-Quality YV12 to RGB Conversion" box is checked.

2c) Does Dithering only work when converting from YCbCr to RGB24/32? What about RGB64? Is it redundant to have the Deband filter turned on when the LAV Video Decoder is outputting YUY2 (see question 2b above)?

3) When outputting to YUY2 solely in the LAV Video Decoder, does any kind of dithering happen? Is there any way I can turn this off, so that ffdshow's raw video filter can take care of dithering instead?

4) Does ffdshow's raw video filter support all of the colorspaces supported by the LAV Video filter? If not, would anything bad happen to the video's colorspace? Would you recommend that I should just output YV12/YUY2 from LAV and then convert that to RGB32 in ffdshow?

Thanks! :-)

[raffriff42]

>> 1b) What about the Avisynth filter? What colorspace does it work in?
AviSynth works with all 8-bit colorspaces. To display the the color format that AviSynth is receiving, enter the following AviSynth script:

return Info

You can move the AviSynth filter up and down the order to see the colorspace at any point in the ffdshow filter chain.

My guess is that - like AviSynth, VirtualDub, and ffdshow's parent ffmpeg - filter processing works in the incoming format without conversion, if at all possible. Some quick tests confirm this. I looked at Picture Properties, "RGB gamma" and Levels with "Force RGB" enabled. Placing AviSynth Info after either filter shows a conversion to RGB (of a YV12 source) is taking place if the RGB-related option is checked, but not otherwise.

As for all the other questions, I don't know. If the Info trick does not help you answer them, you'll probably have to examine the ffdshow source code.

[Cuttlefish]

Thanks for the information. :-)