I want to EXPORT TRANSPARENT BACKGROUND VIDEO BUT ITS NOT WORKING !!!

[MHKsayem]

Hello kindly help me out on this please!!!
i've tried almost every way to export BLACK BG video as a transparent video By using
 
1. QUICK TIME> RGB&ALPHA> ANIMAITON> RENDER (not working)
2. USING MEDIA ENCODER>Apple alpha>RENDER (not working)
3. TIFF Image seq> RGB&Alpha> Render> (not working)

[kglad]

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[Warren Heaton · Accepted solution]

If you want the black that's already in the video to become transparent, you'll need to knock it out prior to rendering with any of the options that you've listed.

You could try applying the Black & White effect followed by the Levels effect to turn the movie file into its own Luma Matte to knock out the black.

Effects > Color Correction > Black & White and Effects > Color Correction > Levels used to create Luma Matte in a pre-Comp

I tried using the "Alpha from Lightness (Unmult)" Effect preset, but it knocks out too much.  So does the 3rd party "Unmult" from Maxon Red Gaint.  A levels adjustment prior to applying either of those might help if you try those.

But I'm thinking of rendering the movie as an Image Sequence and then recording a Batch Action in Photoshop to remove the black with the Magic Wand Tool and Layer Mask (and maybe a slight, 0.25 pixel Gaussian Blur of the resulting Layer Mask) will give better results.  Then import that Image Sequence into After Effects.
Magic Want used in Photoshop to select the background then a Layer Mask applied to hide it.

Once the black has been knocked out, that will carry forward using the Render Queue "with alpha" Output Module templates or the Media Encoder Queue "with alpha" presets.

[MHKsayem]

Thanks, Bro!!!!!!!!!!!!!!!!!!!!! take love
Your answer is correct and I also figured out some ways that worked which are
1. Effect and Presets>Extract
2. Effect and Presets>Shifter 

[Ko.Maruyama]

If you're trying to remove the black areas - make sure that there is an alpha channel there.
(If you're using this graphic in a blending mode that disregards the black pixels - that blending mode can be applied to the resulting video as well)
Check to make sure that the source alpha is interpreted correctly - throw the transparency grid on before you render it out.
Make sure that you don't have any additional layers in your comp (no "black solid" at the bottom).

[Photoshop: It should be relatively easy to get a super clean alpha on the edge of the graphic using the photoshop pen, or maybe even simple channel selections, the interior dark areas are just islands.]