-
Black rendered as gray
Hi,
I have a HF100 AVCHD clip and when I render it in Sony Vegas Platinum 8.0d using WMVHD (tried all profiles), the black levels go up and become gray. When I use other editing programs like tmpgenc I don’t have this problem.
If I use uncompressed AVI I do see correct black levels. I also generated a solid black color before the clip and it was rendered correctly as 16,16,16 (RGB). However the AVCHD clip always jumps up to 30’s. Any ideas how to fix this?
Thanks!
Luc -
6 Replies
-
I rendered out the file that you gave a link to in the other forum dropped it on the Vegas timeline.
Black levels were identical so I suspect Windows Media Player is doing something to it.
I also tried playing it with Media Player Classic and the blacks were where they were supposed to be so I’m positive it’s Window Media Player that’s the problem.
Unfortunately I don’t know enough about WMP’s various options to tell you what to tweak on it. -
I think I understand now what’s going on. The WMV file produced by tmpgenc shows a median luminance of 25 in the histogram (and the original AVCHD shows 32). But the Vegas generated WMVHD file shows same median as the original file.
So Vegas need to change the color space from 16-235 to 0-255 but doesn’t. The broadcast filter doesn’t do that it seems (at least I saw no difference). So no idea how to solve this? Is there a setting?
-
The broadcast filter is designed to bring video levels to legal limits which is the opposite of what you want.
What you need to do is to convert Studio RGB (16-235) to Computer RGB (0-255).
The easiest way to do this is to apply the “Secondary Color Corrector FX” to the clip and then select the “Studio RGB to Computer RGB” preset.
You’ll see the blacks get blacker and the whites get whiter. -
Thanks a lot, that fixed it:-). I reported the issue to Sony.
-
If you can wrap your head around the technical terms, Glenn Chan has some excellent articles on his site about these issues, specifically the two “Color Spaces” articles.
-
I got a suggestion from Sony to use this 2nd workaround which seems to work with this particular file. Question is it a better general workaround than using the computer RGB:
“When I tested with this file, if I set the project properties in Vegas to 32-Bit Video Processing rather than 8-bit before I rendered that, the color and light seemed to render with much better accuracy. To set this, go to File / Properties / for Pixel format, choose 32-Bit Floating Point, and for Compositing Gamma, choose 2.222 (Video)”
I think the gamma change is really what’s changing this. Is this a good method?
Thanks!
Reply to this Discussion! Login or Sign Up