Generally, highly-compressed media, such as H.264 or HEVC, does not include alpha (transparency) information. However, last week, Dan D. sent me the following update. He writes:
This may be of interest, Larry, so I thought I’d pass it along. I found a way to make a much smaller file with alpha channels using the HEVC codec. It is possible! It’s something Apple just introduced last year, and it’s only supported on devices running iOS 13, tvOS 13, or macOS Catalina.
The first option can be used for any video created in any Mac application that includes transparency. The second option is specifically for FCP X and/or Compressor. The advantage of the first option is it can be used by anything. The advantage of the second option is that you can customize the compression settings.
OPTION 1
The resulting movie will be much smaller and retain the transparency information. This technique will work for any video that contains transparency, but requires macOS Catalina or later.
OPTION 2
Open Apple Compressor and create a new Compressor setting using QuickTime Movie. In the Video encoding settings:
This setting can be accessed directly, using Compressor, or Final Cut Pro X, using Share > Send to Compressor.
Then start the batch.
Both options create a .mov with alpha channels that is dramatically smaller than before.
Larry replies: Thanks, Dan! I did not know this was possible.
7 Responses to Include Transparency (Alpha Channels) in HEVC Video
hi, is there any way to do the same on windows ?
John:
I don’t know, because I don’t use Windows.
However, you may be able to do this in After Effects.
Larry
Hi there! So I’ve tried this methods with different exports of a prores4444 w/ alpha and keep getting the same result – following Option 1, and clicking to ‘preserve transparency’, I’m given a HEVC file ‘with Alpha’ by all accounts, but the file actually has a black background baked into it after conversion, and there seems to be no solution. I also tried the method of trying to export a 4444 file from Quicktime as HEVC with transparency expect when opening this file type in quicktime now (prores4444 w/ alpha) – it doesn’t give me any of those ‘HEVC’ and ‘Preserve Alpha’ click box options that it used to – it just wants to export (I even tested opening an Mp4 to see if atleast the HEVC option its shown to me and it is – so I have no idea whats going on now). I’m hoping someone else has had the same issue and can help because this is doing my head in. My developers need this so they can put animated text that is also support by Safari, expect there is never a simple way to actual covert files to HEVC while preserving the alpha channels – you’d think it would be easy to do through Adobe etc. but its just not a thing thats actual part of a normal video industry environment. (As a side note to cover all bases – I’ve already produced a vp8 w/ alpha to be used on Chrome browers, and we’ve already explore the PNG sequence route previously without great success for the developers).
K:
Interesting. I just did a quick test. This still works as I describe using Option 1 – Services.
However, I was not able to retain the alpha channel when compressing it using Compressor. Also, I discovered, that the alpha channel is only supported, in Compressor, using an 8-bit compressed file, not 10 bit.
Hmmm… This will need more research, but at least Option 1 still works.
Larry
I’ve tried both methods. I get the transparent video transferred to my phone and I know the size is 1280×720 hevc. Everytime I try to add the overlay to Lumabooth on my iPhone 13 Pro Max, i get an error saying “the selected overlay is 1280×720, and is not the required size. Please select a different overlay that is exactly 1280×720.” So what could It be? Thanks
DJ Tavo:
I have no idea. Time to call Apple support.
Larry
I am getting the exact same error message,