Banding in WB BD releases

[Ruined]

I've noticed some people and editors (*cough*Dan Ramer*cough*) have noticed banding in certain WB titles and attributed this to a VC-1 encoding artifact or low bitrate problem. Stacey Spears gave us some insight on AVSFORUM why banding raises its head and usually it has nothing to do with encoding or bitrate, but rather the master downconversion to 8bit that must be done prior to encoding. Remember, Blu-ray does not support "Deep Color" for video streams, and hence all masters on Blu-ray must be converted to 8bit before encoding.

In this post, check out the pics:
Video pre-processing - AVS Forum

He demonstrates the difference between a master that has been downconverted using Microsoft's xScaler advanced dithering algorithm (left pic) vs generic 8bit rounding (right pic). As you can see from the differences, the banding artifacts on the right pic are much worse.

Now, despite Warner - who does encodes in-house - using the VC-1 codec, they apparently have not licensed Microsoft's xScaler dithering algorithm. Hence, there are banding artifacts in some of their HD releases due to their less advanced 8bit downconversion tool - it is more noticable on CG than film. On the other hand, many studios like Paramount, Disney, and others all use the same external house which does use Microsoft's dithering algorithm. So, Beowulf domestic HD DVD, for instance, had its master dithered to 8bit using MS' xScaler software but was then encoded in AVC for Paramount. On the other hand, Beowulf international had its master rounded to 8bit by Warner, resulting in banding prior to the VC-1 encoding process even beginning.

I thought it was useful to know the source of banding some find in WB releases - it appears it is due to their using a less advanced tool to downconvert the master to 8bit prior to encoding, and has absolutely nothing to do with video codec or bitrate. Authoring houses that use xScaler dithering, on the other hand, will have a better final output without the banding artifacts - assuming they don't screw things up another way later down the line.

[videoworx]

I mentioned this over a year ago, when you called out "Deep Color" as a marketing gimmick.

I'm hoping down the line we get a Profile 3.0 player that supports 10 bit colour (as AVC supports it). BTW, there are plenty of dithering tools out there to reduce banding. Authoring houses are just lazy (and keen to use software they do not fully understand).

[jbat31]

Looking at both, i can hardly tell a difference.

[Pirate]

Originally Posted by jbat31

Looking at both, i can hardly tell a difference.

It's actually pretty pronounced in the second image. Turn the brightness on your monitor up and you should see it.

[Derb]

Originally Posted by jbat31

Looking at both, i can hardly tell a difference.

Same here.

In fact the last pic of the fishies looks the worse than the original. Was that the point to show off the banding?

The first animated pic(s) also suffer from banding too.

If & when Deep Color ever arrives wouldn't we have to sell our thousand dollar displays for another?

Geez, just be happy with what is currently available already!

[videoworx]

If & when Deep Color ever arrives wouldn't we have to sell our thousand dollar displays for another?

There are a bunch of plasma and LCD displays that have supported 10 bit (deep color/X.V. Color) for a year now (camcorders that record to AVC can utilize it, so the displays have been out there to show the benefit of it).

[Ruined]

Originally Posted by videoworx

I mentioned this over a year ago, when you called out "Deep Color" as a marketing gimmick.

I'm hoping down the line we get a Profile 3.0 player that supports 10 bit colour (as AVC supports it). BTW, there are plenty of dithering tools out there to reduce banding. Authoring houses are just lazy (and keen to use software they do not fully understand).

Deep Color is a marketing gimmick because it is useless based on current BD spec. If BD spec was changed to include it, then it would be useful. But since that hasn't happened and has no signs of happening, it remains a marketing gimmick.

After all, in order for Deep Color to be compatible with older BD players you'd likely need to have two entirely different encodes of a movie, one at 8bit and one at 10bit. So it is extremely doubtful this would ever happen, and it will make Deep Color a marketing gimmick until the next HD format that actually uses Deep Color arrives.

[Ruined]

Originally Posted by Derb

Same here.

In fact the last pic of the fishies looks the worse than the original. Was that the point to show off the banding?

The first animated pic(s) also suffer from banding too.

The point was to show how different downconversion methods from the master can give significantly different results; every master essentially needs to be downconverted in order to be compatible with BD. The very low color/bitdepth fish pictures were put there to make the difference between diffusion, rounding, and other types of downconversion more obvious to those who couldn't see it in the high color/bitdepth pictures.

If & when Deep Color ever arrives wouldn't we have to sell our thousand dollar displays for another?

Deep color is here already and supported by both many BD players and many displays. The problem is Deep Color is not in the BD spec and cannot be added easily, so it is a useless feature at this point in time.

Geez, just be happy with what is currently available already!

Of course, that is another option

[dugpa]

Originally Posted by videoworx

I'm hoping down the line we get a Profile 3.0 player that supports 10 bit colour (as AVC supports it).

I'm sure they will. How could they resist reissuing all the discs with 10bit colour and getting to resell us all the same films yet again!