View Full Version : Video colour space & codecs

10-02-2012, 04:43 AM
For many years we have been rendering animations from LightWave as TGA sequences and using SpeedEdit to convert those to Speed HQ 4:2:2 .avi to archive and to edit.
Now our output is HD and usually in 3D & always displayed via a computer of some sort.
We are noticing that when we look at our TGA output files on our best PC monitors we cannot see any banding or artifacting (particularly in skys), but when we watch (or pause) our video output (as SpeedEditit HQ - not after compression to something to send to our clients) we can see banding & blotchiness.
This would suggest to me that we need to use some other form of video file to convert our TGA sequences to, but what ?
I think the problem is with colour space rather than codec, but I'm no video engineer (& don't want to be).
We're not overly concerned with file size, but very concerned about image quality (bunch of architects!).

10-02-2012, 06:25 AM
And are you using the sRGB colourspace in LightWave? I presume your skies are images? Are they HDRs?


10-02-2012, 06:30 AM
linear colour space, HDRI skys, note I pointed out that the individual TGA images do not exhibit banding, but after being turned into Speed HQ 4:2:2 avi we can see banding & artifacting, and on other subtle stuff as well as skys.
The render seems fine, it's the video colourspace/codec format we're worried about.

10-02-2012, 06:34 AM
When you say Linear, do you mean that all the dropdowns are at Linear in the CS tab? That actually means you *aren't* converting. :) It would be better to use sRGB, especially if the destination is the computer screen. I don't know if that would also help with the codec, but it may do.


10-02-2012, 08:17 AM
Have played with colour space to get advantage of linear workflow as recommended after it became available in LW, sRGB not being much use for the type of artily lit interior stuff we do a lot of.
At present have been all set to Linear, lighting is fine, much work gone into it output TGAs are EXACTLY right for both interior & exterior stuff on the computer screen. And the other end of the studio is complaining about the same thing happening in stuff rendered to TGA sequence in (sob, sob) MAX .
It's when we turn it into avi files the problem starts, the colour, gamma, contrast & everything are fine, the occasional bit of banding & artifacting are not.

10-02-2012, 08:34 AM
You're not actually taking advantage of linear workflow Adrian, you're using LightWave exactly as it was in 9. HDRIs do not need conversion, but any JPGs, TGAs, PNGs, etc. that you use are being over-corrected and your lighting is dropping off too fast when you have everything set to Linear, trust me. Also, for the codec have you tried Lagarith? It uses the same compression as PNG, meaning you lose no image fiability.


10-02-2012, 08:57 AM
Thanks Ben,
looking back at scenes generating recent exteriors, colour space settings as attached jpg does that look right ?
I'll try the codec !

10-02-2012, 09:01 AM
I'd just use the sRGB preset from the dropdown, but turn off Convert 8-bit to Float.