Alpha Channel Video for Stream Overlay

Forum|Forum|7 years ago
December 27, 2018
4 replies
5447 views

Hi all,

I have googled my little heart out trying to find a solution.. if there even is one..

Long story short, I have been asked to create a small set of animations to be used as a streamers cut scene transition..

The clip has a transparent background and will not be used in any other post production - it simply needs to be the video file with the transparent background.

I have exported out as lossless with animation and this does work.. however the file size is 1GB for an 11sec clip - Any suggestions to reduce this at all?

Thanks!

P.s I am no means an expert at this.. kind of learning as I go..

This topic has been closed for replies.

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Warren Heaton10841144

Adobe Expert

Just adding some more options:

a. In the After Effects Render Queue, use the "Lossless with Alpha" Output Module instead of the "Lossless" one. The file size will still be large.

b. (Important note: this approach is by no means ideal and should be avoided, but...) Send the Comp to Adobe Media Encoder and then click the Add Output button so that you've two outputs for the Comp. Set the 1st output to H264 Match Source - High Bitrate. Set the second output to the same thing, but click on Match Source - High Bitrate and check "Render Alpha Channel Only" in the Render Settings. This will give you two files: the video and its corresponding "hold out" matte. It's pretty old school to do it this way and H264 is a terrible format for it. But, compression generation loss and interframe compression issues aside, it'll work (assuming the person you give it to knows what to do with a hold out matte (a.k.a. Luma Matte).

Roei Tzoref

Brainiac

Prores4444 will be smaller most of the times than quicktime animation And in cc2019 you have it on windows too. Also gopro cineform. You can also use mxf OP1A Jpeg 2000 in Adobe media encoder. in you have an Ae version prior to cc 2018, then Quicktime PNG will probably give you the best compression.

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Dave Merchant

Brainiac

ProRes 4444 has a target bitrate of 330MBps at full-HD. An 11 second clip would be 3.6GB.

Roei Tzoref

Brainiac

yes that's the pure math. an estimation. doesn't mean the file will actually be that size, especially when animation and transparency is concerned. Quicktime Animation will produce a larger file size. ProRes will be most of the time smaller file size than animation. that 11 second clip could be half or even third of that QT Animation file. it all depends on the pixels, the animation/video changes over time , and transparent areas.

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Dave Merchant

Brainiac

ian.taylor@tpmedia.co.uk wrote
the file size is 1GB for an 11sec clip - Any suggestions to reduce this at all?

A compressed image sequence (TIFF or PNG) might be smaller if most of the screen area is empty or solid color.

Mo Moolla

Brainiac

Yes but only TIFF and PNG. If he goes DPX it will be bigger

Mo Moolla

Brainiac

Take this file in Media Encoder and use a H.264 codec

It will substantially drop the file size down based on the bitrate you choose.

Higher the bitrate higher the file size.

In ME you will be able to see the export file size before you render so as u play with bitrate you will be able to find a comfortable resolution and size to suit you

Mo