Originally Posted by Seeco
There's just no end to it, is there?
That is what I said in my first reply
. Most people are not watching accurate video on their PCs. Sad, given where I used to work
This dithering you mention, does that mean that if it (the codec?) didn't apply dithering when going from 16-235 to 0-255, then it could convert back to 16-235 without any loss whatsoever (it would just have to "do the math")?
Yes and no. If like I showed, rounding was used, then inverse conversion works. But if the values were simply truncated, then accuracy is lost and inverse conversion gives you something different.
Right now what I'm seeing is banding in PC games on my HTPC, what does this mean?
Well banding could be a function of your display not handling the source properly. That is above and beyond the case we are talking about here.
Now, if the display is set to 16-235 and proper conversion with dithering is not done, then that could be responsible for it.
If it works as it should, the games (which are 0-255 as everything else) should be converted to 16-235 via the HDMI dongle. How does this produce banding?
If you do any conversion where there is fractional values, as is in this case, you are going to need to dither. If you don't dither, you get banding. In this case, you may also be going to YUV domain and as such, have color space compaction to boot. And dithering is required here too for proper operation.
According to you and to what I can see myself, what I have now is video with noise and games with banding. I guess that if I applied the tweak setting everything to 0-255, didn't use the HDMI dongle and set my TV to 0-255, then everything would be perfect except for video which would show banding, right? I guess PC:s really aren't meant for this...
PC is a multi-function device. Unfortunately, the people who designed video standards and PCs did not talk to each other much. The result is a complete mess as we have discussed.
In an ideal case, your display would go into RGB 0-255 for graphics/desptop/game work and YUV 16-235 for video. Even if it did this, then your video better be in full screen as otherwise, either the graphics of video would be wrong.
From memory, Windows Media Center gets around this problem by rendering its graphics in the same mode as video. That way, you can set up your display for video and have it all be right. Of course, that only resolves the graphics displayed while inside MCE, not outside.
So the best solution really is to dedicate a PC to video and have that path be correct. Or, just don't let the errors bother you