Digital Juice, compression, alpha channel

[Christopher Glaeser]

I'm working on an SD DVD project in Premiere CS3 and have added some Digital Juice backgrounds, lower thirds, and swipes. Some of these elements include an alpha channel. The DJ documentation recommends using QuickTime Animation with Alpha for rendering these elements. This results in about 1 GB per minute in file size. A similar avi or wmv file (without alpha channel) is a small fraction of that size. I have plenty of disk space so this is not a serious problem, but it just seems like a waste of disk space and bandwidth for these elements with alpha channel.

I happen to own Aspect HD so I thought I would ask, does it make sense to try the Cineform codec. I suppose I could just try it and see what happens, but I wanted to make an educated guess first. Any suggestions or comments? I posted this question on the DJ forum yesterday, but so far no suggestions for improvements over QT Animation.

Best,
Christopher

[David Newman]

We definitely improved things a lot over the animation codec, we can do alpha 4:4:4:4 RGB encoding with significantly compression than the animation codec. However, we only offer 4:4:4:4 encoding in NEO 2K and Prospect 2K. To can try either of those products to see how much smaller and more handy your Digital Juice become.

[David Newman]

Could you please point me to the DJ forum thread so I can add a reply?

[Christopher Glaeser]

Originally Posted by David Newman

Could you please point me to the DJ forum thread so I can add a reply?

See http://www.digitaljuice.com/communit...tm.asp?m=75518

Best,
Christopher

[Christopher Glaeser]

Originally Posted by David Newman

However, we only offer 4:4:4:4 encoding in NEO 2K and Prospect 2K.

Two quick questions:

1. Is 4:4:4:4 the only Cineform encoding that supports an alpha channel?

2. Digital Juice can render the video separate from the alpha. Could I use the Aspect HD CFHD to render both clips and put both clips on the Premiere timeline as though it was one clip of video + alpha?

Best,
Christopher

[David Newman]

1. Yes.

2. I never tried that, tell me how to do it.

[Christopher Glaeser]

Originally Posted by David Newman

2. I never tried that, tell me how to do it.

In Juicer 3, select an asset that has an alpha channel (e.g. full screen wipe, lower third, etc). In the Output settings, there is an option "Render Alpha Separately". This will render two clips. One clip is the video and the other is B&W of the alpha channel.

I think these two clips can be put on the Premiere timeline and made to behave like a video with alpha. Perhaps someone can help with this step.

I'm certain it can be done in AE; just curious if it can be done in Premiere with results comparable to QT Animantion with Alpha, but with considerably less storage.

Best,
Christopher

[Steven Gotz]

The Alpha channel is exported monochrome, I believe, and can be used as a Track Matte for the other footage.

[David Newman]

These two files will give you an effective 4:2:2:4 color sampling, while not 4:4:4:4, it is still pretty good. Someone please try both methods are post on their experience.

[Christopher Glaeser]

Originally Posted by Steven Gotz

The Alpha channel is exported monochrome, I believe, and can be used as a Track Matte for the other footage.

Yes, do you know the specific details of doing this in Premiere? For example, do you use an effect? I read through the Premiere documentation and did not see anything that addressed this specific issue.

FOUND IT! Video Effect->Keying->Track Matte Key->Matte Luma.

Best,
Christopher