Questions tagged [alpha]

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35 views

ffmpeg prores alpha channel quantization looks pretty bad

Might be related to this other ticket? I've been doing some prores tests for both color and alpha. Usually this isn't a big deal since my alpha channels are solid with a 1-2pixel transition to black....
0
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1answer
57 views

ffmpeg prores alpha channel not present when colormatrix and colorspace operations are performed

So I've figured out how to convert images to prores with no colorspace shifts using either: -vf colormatrix=bt601:bt709 filter for 8bit material and -vf colorspace=all=bt709:range=pc:format=...
1
vote
1answer
11k views

Make white background in MP4 movie transparent

I have a short animation clip made with PyMOL software (visualizing molecules), in the MP4 format. I am going to use this animation in future presentations, and it would look much better if the ...
2
votes
1answer
2k views

Create Alpha channel-Videos (obs stinger compatible) with ffmpeg and 2 files

I have 2 video files. One file is the main content and the other file has an alpha channel emulated with black and white (white = opacity 100 and black = opacity 0). Sometimes the emulated alpha ...
2
votes
0answers
222 views

FFMPEG drops end frames when converting a unmatted alpha .mov to .webm using ffmpeg but converts fine when alpha is premultiplied?

I am using ffmpeg to convert a straight alpha .mov to a webm so I can layer videos on top of one another for a web game however when converted the duration is the right length but the frames freeze ...
0
votes
1answer
454 views

ffmpeg fade to specific color values over time

I have a background image that I'm trying to fade to specific color values using this filter: lutrgb=enable='gte(t,3)':'r=0.3*val:g=0.3*val:b=0.3*val' This almost works, but it changes the values ...
0
votes
1answer
207 views

Using brush tool for alpha channels/rotoscoping in after-effects

I'm trying to rotobrush/rotoscope a bunch of footage, see image below for what I mean. Currently I'm using the rotobrush, but it is too time-consuming and slow - it keeps trying to guess the paths, ...
0
votes
1answer
450 views

What is the difference between RGB and RGB + Alpha?

I know what is Alpha channel but when I rendered a motion logo using RGB and RGB + Alpha in After Effects, I didn't see any difference. So what's the basic difference between them and how to decide ...
7
votes
3answers
13k views

Is it possible to export a Video with transparent Background? (No Image Sequences!)

Is it possible to export a video file from After Effects with transparency? I don't want to export to an image sequence.
1
vote
0answers
62 views

export a video from Blender with alpha channel

I have a problem exporting a video from Blender (Cycles Render) with Alpha Channel. Generally it's a scene with sailplane flying about a camera positioned near to the floor. In addition to this it is ...
2
votes
1answer
93 views

Is it possible to mask out unsharp areas of footage with After Effects?

Is there any existing filter/effect, that will automatically mask out the unsharp area of my footage? Let's say I have an object in focus and a lot of depth of field. How do I show only my sharp ...
2
votes
1answer
595 views

Maya batch render missing alpha channel

I'm trying to export a scene to composite in Nuke. When I "render current frame" and save the image from there, I get an image with an alpha channel, but when I batch render the images don't have the ...