View Full Version : Blacker than black a.k.a. BTB a.k.a. below reference black in Linux


Blerghass
01-07-09, 07:56 PM
When I play video from my Linux HTPC on my TV, all data below reference black (16) is lost. The computer takes the range 16-235 and expands it to 0-255 before sending it to the TV. I don't want to lose this data. As a result, DVDs look different when played on a DVD player compared to when played on my HTPC.

I've read that VMR9 can preserve the blacker than black data, but I don't think it is available in Linux. Does anybody know how to send the blacker than black data intact to the TV in Linux?

I learned this information in this thread: http://www.avsforum.com/avs-vb/showthread.php?t=523614

I am running Mythbuntu, and my video card is a Radeon 9600. My TV is a Panasonic plasma 42PX75U.

Rgb
01-07-09, 08:10 PM
DOn't know if you're involved with this thread at phoronix

http://www.phoronix.com/forums/showthread.php?t=12020&page=2

but lots of good discussion re the black/white range issue- don't know if there's any solution there...

Perhaps Nvidia cards/drivers handle BTB better than ATI?

Rgb
01-07-09, 08:14 PM
It appears the BTB bug is fixed for Intel GPU's

https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/105656


which also mentions mplayer as handling the black-white range properly.

Bugs submitted for ATI and Nvidia?

Blerghass
01-09-09, 08:14 PM
Thanks for the links. It seems that if I use TexturedVideo + xv my PC may output video without moving black from 16 to 0. I will give it a try and post again with my results.

I find it interesting and troubling that the people from your links are trying to get rid of the very thing that I need. They want all video players to expand 16-235 to 0-255. I just want to find some mode that won't do that.