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yuriythebest
08-28-2007, 10:36 AM
I'm trying to output an image sequence into avi using combustion, however the video quality is extreemly low. In DivX settings I've even tried setting the bitrate to max, and set DivX to HD (my video is in high def), that didn't help. Also why can't I make the output 16 bit?

http://img211.imageshack.us/img211/2518/videobadqualitydd0.jpg (http://imageshack.us)

http://img250.imageshack.us/img250/6748/settingsye5.jpg (http://imageshack.us)

EricNS
08-28-2007, 11:58 AM
Hi,

What you have here is color banding. It's a problem with 8 bit per channel images. 256 shades of color are often not enough to encode correctly soft gradients. The Steps become visible. Combustion is not to blame here.

The solutions:

-Work in 16 bit.
-Use a strong dithering or film grain, to "break" the gradient. This is the only solution if the final output will be in 8 bit (like for mpeg2 DVDs).

You selected the AVI (DivX) codec. This format offers only 8 bit per channel.

yuriythebest
08-28-2007, 01:56 PM
Hi,

What you have here is color banding. It's a problem with 8 bit per channel images. 256 shades of color are often not enough to encode correctly soft gradients. The Steps become visible. Combustion is not to blame here.

The solutions:

-Work in 16 bit.
-Use a strong dithering or film grain, to "break" the gradient. This is the only solution if the final output will be in 8 bit (like for mpeg2 DVDs).

You selected the AVI (DivX) codec. This format offers only 8 bit per channel.

Thanks for the prompt reply! I rendered it out in quicktime PAL. The pixelation is gone but the color quality is somehow still lower- the image is much less brighter/colors are more dull than in the original. How do I switch to 16 bit? When I click create new composite I select 16 bit but in the render dialog as shown in the screen only 8 bit is allowed. What format/codec should I render to?

scrimski
08-28-2007, 02:35 PM
What do you need it for? What codec is that QT PAL anyway?
PAL itself isn't even real 8 bit, it's limited to values from 16 to 235 instead of 0 to 255.

yuriythebest
08-28-2007, 03:01 PM
What do you need it for? What codec is that QT PAL anyway?
PAL itself isn't even real 8 bit, it's limited to values from 16 to 235 instead of 0 to 255.


please tell me which format/codec I should use for HD (1280*720) animations? DivX has a setting for high definition but as seen in the image at the beginning of the thread the quality is very bad for some reason even with the maximum 8 megs of bitrate. Btw the input format is in a 24 bit targa sequence.

EricNS
08-28-2007, 07:48 PM
Like scrimski said, PAL is even lower than 8 bit per channel, so avoid it! Use something like Quicktime with the "Animation" Codec, or a Tiff or Targa sequence. Image quality is not the issue here. You can use DivX at the highest quality, you'll still get color banding.

If you want really want to switch from 16 to 8 bit, add a "Bit Depth Converter" operator. It's not a perfect solution, but it works in most cases.

Good luck!

seedo
08-28-2007, 08:36 PM
use quicktime

yuriythebest
08-28-2007, 09:31 PM
did some experimentation.

quicktime & H261, H263 codecs offer VERY low quality

1280*720, quicktime H.264 -best quality, 16 bit= high quality, yet has small 'bumps' and 5 seconds weighs 150 megs

1280*720, quicktime H.264-medium quality, 16 bit=high quality also, 5 seconds 50 megs. Still has jitters from processor strain.

using the avi x264 - H264/AVC encoder makes about the same results only filesize is 100 megs.

I'm very confused- either the filesize is extreem or the quality is extreemly poor. Can anyone give me some nice settings for exporting 1280*720 in nice quality and with a reasonable filesize?

scrimski
08-28-2007, 09:51 PM
Once again: What are you planning to do with those files?
For web broadcasting limiting the framerate down to 18 fps would be a first step. Do not touch the quality settings but the bitrate first. You will have to experiment, start with something like 4000kB/s on a small 10 seconds piece of your stuff with lots of motion/contrast/color in it. If you see artefacts, increase the bitrate, if not, decrease.
If you can afford the time, encode in two passes.
If you use sound, try a codec like AAC with a 33 or even 22 kHz samplerate.

yuriythebest
08-29-2007, 02:31 PM
Once again: What are you planning to do with those files?


a high definition animated short.

scrimski
08-29-2007, 03:09 PM
What way of distribution? DVD/TV or web download?

yuriythebest
08-29-2007, 07:34 PM
What way of distribution? DVD/TV or web download?

web download, though NOT web streaming like youTube, I'm talking about a nice large filesize and a good quality HD video. It will be around 5 mins and I hope it will be around 100-150 megs.

seedo
08-29-2007, 08:10 PM
u asking for alot but here is the deal


i have a project befor that was 6 min, i render it in combustion Pal full quality which was so great and smoth, the file size was 1.7 GB yes GB and i used Divex converter it give me the same quality almost like let say 90 % close to the origonal and the divx converter reduce the size to 47 MB and am not kidding i swear to god.
so try that
thank u

thatoneguy
08-29-2007, 11:49 PM
Quicktime will change the gamma of every movie it makes through H.264, Sorenson etc. that's where the "washed out" look is coming from. You can slap Apple engineers' incompetance for that one.

The banding howeer is not a result of you rendering out at 8bits per channel. If that were the case the JPEG compressed screenshot of the uncompressed image would also be banding. It's completely a problem with your compression settings. Compressing low contrast gradients is easily one of the most difficult challenges for a codec. I would try a VBR 2 pass Divx or maybe give XviD a try.

Every codec has a bit depth limitation. Most lossy codecs are limited to 8bits per channel. It's just the way it is. They *could* make a higher bit depth version but it would only be useful for post workflows since no consumer monitor or TV I know of actually displays 10bits+ of color information

yuriythebest
08-31-2007, 06:00 AM
u asking for alot but here is the deal


i have a project befor that was 6 min, i render it in combustion Pal full quality which was so great and smoth, the file size was 1.7 GB yes GB and i used Divex converter it give me the same quality almost like let say 90 % close to the origonal and the divx converter reduce the size to 47 MB and am not kidding i swear to god.
so try that
thank u


right, so you used an external DivX converter later on? Which one? Can you give a link?

scrimski
08-31-2007, 01:57 PM
http://forums.cgsociety.org/showpost.php?p=4619984&postcount=1

yuriythebest
08-31-2007, 04:49 PM
thanks! greatly appreciated!

seedo
08-31-2007, 08:06 PM
hi:
just visit the divx site and download the divx convertot thats all

lehmi
09-24-2007, 09:07 PM
I learned really quick that combustion is not made for the final output.

Use the divx codec together with virtualdub to go the avi route and h264 together with sorenson squeeze for the quicktime/flash route...

:)

good luck

aglick
09-26-2007, 10:31 PM
"...I learned really quick that combustion is not made for the final output..."

This is true -

Combustion was never designed as a "finishing" or transcoding environment. It didn't even have a timeline or editing tools until v.4. Discrete designed this as a compositing tool - nothing more. It's nice that it has pretty flexible options for file rendering and export...

If you are wanting more precise control over highly compressed exported sequences, then you would want to use a 3rd-party application like Windows Media Encoder, Cleaner, or one of the many other compression utilities...

CurtJ
11-18-2007, 01:22 AM
http://forums.cgsociety.org/showpost.php?p=4619984&postcount=1

Excellent! -- Should this be sticky on the discreet forum too? I know it refers to after effects, but it seems to be just as relevant to combustion, it was definitely a major relief for me when I read it. Thanks

Ahnab
11-24-2007, 08:58 PM
Render it out to Quicktime, set at TGA, Depth at Millions of Colors (NOT Millions+, coz thats with alpha), Quality slider all the way to the right at Best and specify your desired framerate. Simple! :)

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