Render with alpha?

[scrimski]

Microsoft DV sounds like an AVI codec which doesn't support alpha/transparency except for Indeo codec(not sure about that).
Beside that I wouldn't compress anything when I'm going to edit it in an NLE later, I always render into single frame sequences

[Mylenium]

Ok I am rendering a comp that has small amount of animation that I need to overlay into a number of different video's. Is there any way to render the comp with alpha so I can use it in Prem Pro rather than import all of my rendered clips into individual comps?

I have looked in the settings and it gives the option for RGB+Alpha but it is grayed out and not available.

The only way I have been able to render with alph is to select Lossless with alpha or Microsoft DV NTSC 48Khz and turn off the compressions settings but when I do either of those two options I get a 19 second animation loop that is just shy of 1gb in file size.

I feel like a tard with out my helmet! What am I missing?

Thanks!

Well, wake up! Video editing and post effects in general require lots of disk space because most of the time you either want to work with little or no compression. If your system is not up to the task, get another hard drive. You can get cheap 250 GB SATA disks for a little over 100 USD. 1GB for 20 secs uncompressed is normal.

In addition to that, educate yourself. Per se AVIs aren't even meant to support Alpha. Every CoDec that does so, is more or less a hack. Most compressed formats like DV do not fall into that category. CoDecs that do support Alpha are either tied to special hardware that uses them or supplied by third parties. One AVI CoDec that supports this feature for instance is HufYUV. That notwithstanding, you should prefer Quicktime for several reasons. First off it's much more reliable and, which is the important part for you, supports a much wider range of CoDecs, including those with Alpha support. Though it's an old one, the most widely used is the Animation CoDec.

Mylenium

[Riding Death]

Thanks for the info I will give the quicktime format a shot and see how that works out for me. One more quick question that you might be able to answer.

Is avi a compressed format?

Thanks again!

[Mylenium]

Is avi a compressed format?


No, not necessarily. You absolutely do not seem to understand how those things work (no offence). AVI stands for audio video interleave, meaning a combined file from moving pictures and sound. So far so good. Now there are several options how to combine audio and video. The simplest is to write them both uncompressed. As you found out yourself, this consumes lots of disk space and due to the massive data rates playback may not be smooth.

That's where CoDecs com into play, which is short for compresor-decompressor. These are little extensions that either compress the video data or audio or both. This is what you see when you are e.g. choosing between Cinepak, Microsoft DV etc.. Depending on how those CoDecs work, they sacrifice more or less quality.

The one thing that's bad about AVIs is that unlike Quicktime files they don't support multiple video streams natively, hence support for Alpha channels is less than good because every CoDec doing so, has to jump hoops. Quicktime is much more open in this regard.

Mylenium

[Rickmeister]

I allways use Quicktime with the Animation Codec, alpha included. For national television. Works everytime. I allmost never use .avi or .wmv, only for client previewing over the internet with XviD or DivX codecs when they don't have Quicktime.

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