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A
A.I.1
Legend
October 22, 2017
Answered

Best output format for approx 5 mins of 1080p50 video with alpha channel

  • October 22, 2017
  • 4 replies
  • 2329 views

I have a 1920x1080p50 video that is green screen footage (man stood talking against green screen) that is just over 5 mins in duration. I need to compress it with it's alpha channel to a size as low as possible (at least under 2 GB but if possible under 1 GB) to upload online while still maintaining good enough quality and it's transparency and also being readable by Premiere users.

QuickTime Animation codec made it compress to 3.12 GB for just 10 secs.

Webm (VP8 and VP9) didn't keep the transparency even though I said to export + alpha.

I'm having more success with QuickTime Jpeg2000 but I have to keep lowering the quality value and re-trying, but that's the one that definitely shows the transparency (anim codec file does too but is much too big).

Is there any better codec for this please as I need it encoded and uploaded as soon as possible? I thought about uploading a 25 fps version but the client probably wouldn't want that but it might be the only one small enough. Any ideas?

With AE CC 2017

This topic has been closed for replies.
Correct answer Roei Tzoref

Try Quicktime Png. It's my codec of choice for lossless online delivery. It will take the longest time to render but will give the smallest file size.

4 replies

A
A.I.1Author
Legend
October 25, 2017

Thanks for the replies everyone.

Is there any reason why rendering in the webm format (VP8 or VP9 codec) from Media Encoder doesn't export the transparency?

Unlike some of the other codecs that render the transparency properly and show a chequerboard pattern in a video player (and make it transparent in Premiere), rendering with WebM (VP8/VP9) renders a mostly grey background (with the top of the frame showing a bit of green - which shows transparent in other codecs), even though I said "Include Alpha Channel" in the settings screen in AME. Is there a reason why (note: this is including when I set the quality to 72 for VP8)? Is this a bug in AME?

Szalam
Community Expert
SzalamCommunity Expert
Community Expert
October 23, 2017

Alternatively, you could make the video and the matte as two separate videos.

You could also make it compressed with H.264 as an MP4 with no alpha (pick a neutral bg color or leave the green in it). And then render out a black and white matte for the alpha. This can be used as a track matte in Premiere Pro.

    Hussin Khan
    Hussin Khan
    Participating Frequently
    October 23, 2017

    Hi there,

    May I suggest

    Option1

    Rendering into PNG sequence (image sequence). It carries the alpha channel. If you're gonna key it, it wont matter if it's contained in a .mov or a bunch of image files in a folder. I prefer the latter when doing VFX/keying job.

    Option 2

    Breaking the render into few parts - perhaps every 1 minute and adding them one-by-one into a sequence.

    Hope this helps! :-)

    Dave_LaRonde
    Dave_LaRonde
    Inspiring
    October 22, 2017

    I'm sorry, but you are stuck.  There is NO codec that will compress to the size you want and still retain an alpha channel.

    You have no other choice than to endure the large file size. 

    This may mean you must figure out a new way to get your work from Point A to Point B.  A thumb drive comes to mind.@

    A
    A.I.1Author
    Legend
    October 23, 2017

    Thanks. I'll stick to QuickTime & Jpeg2000 for now as that was the best codec for it I could find so far. I can't use a thumb drive for it - it needs to be sent online. Thanks.

    Roei Tzoref
    Roei TzorefCorrect answer
    Legend
    October 23, 2017

    Try Quicktime Png. It's my codec of choice for lossless online delivery. It will take the longest time to render but will give the smallest file size.

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