Deblocking and VideoShader
Posted: 11 Nov 2005 10:13
I've had an ATI Radeon 9700pro for quite a while, and was always impressed by its ability to deblock the output of VLC - the picture quality was always great.
Now I've upgraded to the x800 XL, and it apparantly has "VideoShader HD" technology which I am told improves on the original technology. Anyhow, VLC doesn't seem to know how to use it. The video is blocky as ever. However if I play the same video file with bsplayer, mpc, or even Windows Media Player, the deblocking looks wonderful.
Screenshots are below - it's pretty clear to see just by looking but it's much more obvious at higher zoom. Also I find that it's interesting that the VLC screenshot is half the size of the bsplayer shot. Since PNG compression rate is directly proportional to the number of colors in the image, does this mean VLC is outputting in lower bit color?
If you have a very critical eye, you will see both smaller normal pixelation and what I have termed 'superpixelation' in the VLC image. It's most obvious at light-dark transitions, and it's much more obvious when the video is playing but it is visible in the screenshot as well. I've attached a section of the VLC screenshot with reference lines marking some 'superpixel' borders.
VLC screenshot:
http://img384.imageshack.us/img384/7460/vlc0ot.png
VLC 'superpixel' reference lines:
http://img384.imageshack.us/img384/4672 ... xel7ie.png
BSPlayer screenshot:
http://img384.imageshack.us/img384/5900/bsplayer3iq.png
EDIT: Better example screenshots.
--bsiegel
Now I've upgraded to the x800 XL, and it apparantly has "VideoShader HD" technology which I am told improves on the original technology. Anyhow, VLC doesn't seem to know how to use it. The video is blocky as ever. However if I play the same video file with bsplayer, mpc, or even Windows Media Player, the deblocking looks wonderful.
Screenshots are below - it's pretty clear to see just by looking but it's much more obvious at higher zoom. Also I find that it's interesting that the VLC screenshot is half the size of the bsplayer shot. Since PNG compression rate is directly proportional to the number of colors in the image, does this mean VLC is outputting in lower bit color?
If you have a very critical eye, you will see both smaller normal pixelation and what I have termed 'superpixelation' in the VLC image. It's most obvious at light-dark transitions, and it's much more obvious when the video is playing but it is visible in the screenshot as well. I've attached a section of the VLC screenshot with reference lines marking some 'superpixel' borders.
VLC screenshot:
http://img384.imageshack.us/img384/7460/vlc0ot.png
VLC 'superpixel' reference lines:
http://img384.imageshack.us/img384/4672 ... xel7ie.png
BSPlayer screenshot:
http://img384.imageshack.us/img384/5900/bsplayer3iq.png
EDIT: Better example screenshots.
--bsiegel