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Encoding format for track matte clips?
Hi!
Since I have been working a lot with track matte keying lately I am wondering if there is a more (space)efficient way of encoding the matte clips than what I am doing now.Most of my clips are rendered out from After Effects but I guess the encoding principles are the same in PPro. I encode my clip with the Microsoft DV codec and then another copy of the clip that contains only the alpha channel, also with the same DV codec. So I end up with two equally sized files for each clip. But the alpha channel is only greyscale and should in theory not need as much data as the corresponding full color file.
Since space is an issue for me when archiving material, I wonder if there is an easy way to reencode the matte files to lower sizes without loss of quality (sort of an DV codec for greyscale)?And if there happenes to be an After Effects expert out there, whats the best format to encode the alpha channel to in AE with similar restrictions (less space than full color but same quality as DV)?
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4 Replies
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Have you tried exporting from AE in the uncompressed Animation CODEC using millions+ color space? That should keep pictures and alpha together, but at the expense of more disk space.
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Hi!
Thanks for the input David.
I am really trying to save diskspace so for my archiving purposes that is not a better option. However, for intermediate work in AE that seems like a good codec to use and was recommended by others as well. For archiving I got a suggestion on the AE forum to use Photo-JPEG compression in QT and that seems to be the ideal choise for me since the quality is better and the diskspace required for greyscale clips are much lower.best regards
Joakim -
Disk space is cheap enough nowadays to consider having external or caddied drives on which to store the full-resolution originals instead of cramming everything into corners on the base system. For stills, storing the originals on data CD or DVD is space efficient without losing quality. For short enough projects, original-format video can also be stored on DVD.
Next best is back to tape.
Last resort, in my book, is lossy compression for archiving.
As long as you have no requirement to edit afterwards, then some of the lossy CODECs can be useful, albeit at some hit in quality. WMV has a good name nowadays, too.
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I see your point and I wont argue against it. The reason I am (was) looking at spaceefficient archieving options is that the project at hand was just a few hundred Mb short of fitting on a single DVD and it contained quite a few clips of a person keyed out from a green background. I do not expect to use these clips ever again (this is just some private amateur stuff) but by using the Photo-JPEG on the clips I was able to get a backup of the whole project on a DVD and still the keyed out footage looked better than when compressed with the DV codec (on a project like this I saw no reason to save in lossless and all raw material except for some picture was shot with a DV-cam). So for me there are situations where I do not need to archiev in full quality but I guess If I expect to reuse the footage or if I should do some more professional work, full quality backups are a must.
And as you point out, storing space is cheap these days.Thanks again for your input David.
best regards
Joakim
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