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White video

vvvv beta general
#1

hello,

sorry for this late 2008 extra newbie question…
i’ve made a simple video player and i notice something strange:
when i play a full white video file
FileStream -> VideoTexture (standard not the YUV mixing mode)-> quad -> render
i’ve a greyed white output instead of the full white…
i’ve to put the blend (EX9 renderState) mode : Add
to have the full white…but the blacks are not black any more
so i try with the VideoTexture YUV mixing mode
same problem…
with aviparser or filetexture(white JPG) -> quad : everything is fine…

so my question : how to configure the videoTexture node
to output the real video colors ?
thanks

Nvidia 8600mGT (with the latest Nvidia Laptop drivers)

#2

hola circuit,

this is a known problem that for my understanding has nothing to do with vvvv. from the picvideo codec manual:

Many M-JPEG codecs (including previous versions of PICVideo) have treated YUV input to the compressor as though luminance and chrominance values are in the range of 0 to 255.

However, the actual YUV input to the compressor has luminance and chrominance values which are in the range 16 to 235 and 16 to 240 respectively.

The result of encoding YUV incorrectly is that the resulting video can look washed out and undersaturated.

the picvideo decoder has an option to workaround wrongly encoded videos: Assume Normalized YUV.

not sure about other codecs. so the solution may be either in encoding the videos again or use a decoder that can treat the videos correctly.

#3

hey Joreg,

MJPEG with ffdshow decoder
works perfect

thanks

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