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View Full Version : Codecs that turn black grey, adding audio?!



starbase1
10-07-2009, 02:38 AM
I recently noticed that an animation of mine set in space was playing back with the background as dark grey, not black. I checked everything and eventually traced it to the codec (xvid). I then recompiled the image sequence with various other, (including MS offerings), and once my attention fouicssed on the background, I started to see problems all over the place, (or colour shifts in the foreground, or just plain poor results for the file size)

Given that the range between black and white is often given as a measure of screen quality, I'm more than a bit surprised that any codec would choose to lighten blacks...

And as someone who loves to do space scenes, I'd really like to fix this!

So what codecs do people recommend for this sort of thing? Must be able to handle full HD!

While I am at it, is there a prog that will simply attach audioo to a video file? Very often that is the main thing I want to do with what comes out of LW, and going through a full blown video editor seems overkill...

erikals
10-07-2009, 04:22 AM
dang' good question... http://www.newtek.com/forums/images/smilies/brians/aiwebs_017.gif

starbase1
10-07-2009, 04:52 AM
Now all we need is a dang good answer then...

Lightwolf
10-07-2009, 05:30 AM
While I am at it, is there a prog that will simply attach audioo to a video file? Very often that is the main thing I want to do with what comes out of LW, and going through a full blown video editor seems overkill...
VirtualDub (http://www.virtualdub.org)... which also does a lot more if you want it to.

Cheers,
Mike

erikals
10-07-2009, 06:41 AM
wonder if it is the video codec itself, or if it is a gamma setting in the player...

erikals
10-07-2009, 07:01 AM
yup, over here, it had something to do with the gamma....

setting it from 1.00 to 0.80 helped...

Silkrooster
10-08-2009, 09:40 PM
Hmm... I wonder if that codec had the intentions of being used for TV. It sounds like it is clipping the black and whites for NTSC. The little I used that codec, I haven't noticed it though.

starbase1
10-09-2009, 12:14 AM
yup, over here, it had something to do with the gamma....

setting it from 1.00 to 0.80 helped...

I thought gamma did not affect the whiote and black points, just the curve between?

Silkrooster
10-09-2009, 12:20 AM
I thought gamma did not affect the whiote and black points, just the curve between?

Thats the way I understood it. Gamma is the mid tones.

erikals
10-09-2009, 01:11 AM
nope. fix it here at least...

starbase1
10-09-2009, 01:25 AM
nope. fix it here at least...

Thanks for the observations- I'm wondering if your monitor is set darker than mine, so the difference does not show?

Anyway,here's a screen grab of the vid playing in GOM player.

starbase1
10-09-2009, 01:30 AM
And if anyone would like to see the vid, (now with sound thanks to VDub!), I've put it here:

http://www.starbase1.co.uk/rwhd.avi

About 15 Mb, of a flight across Ringworld, in HD. Sound track was generated with Smartsound, which I am rather impressed by!

erikals
10-09-2009, 08:15 AM
videograb of Nvidia gamma settings...

toby
10-11-2009, 12:59 AM
Lossy compression codecs do seem to lift the blacks, and I think it's to reduce the total amount of colors stored and reduce file size. Reducing the gamma on your display device will darken it, but it'll also darken greys that are supposed to be grey, on everything on your screen. I've seen professionally compressed video that's pretty dark, maybe it's something they save for the pro software.

toby
10-11-2009, 01:45 AM
And if anyone would like to see the vid, (now with sound thanks to VDub!), I've put it here:

http://www.starbase1.co.uk/rwhd.avi

About 15 Mb, of a flight across Ringworld, in HD. Sound track was generated with Smartsound, which I am rather impressed by!
This looks pretty dark to me, maybe your monitor's set too bright?

I just tried a re-compression of an h264 video, using h264 in quicktime, and there's some absolute 0/black areas, have you tried h264?

erikals
10-11-2009, 03:45 AM
Lossy compression codecs do seem to lift the blacks, and I think it's to reduce the total amount of colors stored and reduce file size. Reducing the gamma on your display device will darken it, but it'll also darken greys that are supposed to be grey, on everything on your screen. I've seen professionally compressed video that's pretty dark, maybe it's something they save for the pro software.

actually you are right, i think i recall i have seen some .movs that have displayed dark black also...

erikals
10-11-2009, 03:47 AM
This looks pretty dark to me, maybe your monitor's set too bright?

I just tried a re-compression of an h264 video, using h264 in quicktime, and there's some absolute 0/black areas, have you tried h264?

this show how bright it was on my monitor...
http://www.newtek.com/forums/showpost.php?p=934757&postcount=13

starbase1
10-11-2009, 04:12 AM
This looks pretty dark to me, maybe your monitor's set too bright?

I just tried a re-compression of an h264 video, using h264 in quicktime, and there's some absolute 0/black areas, have you tried h264?

No, but I will!

Thanks for taking the time to experiment!