Questions tagged [alpha]
The alpha tag has no usage guidance.
29 questions
0
votes
1
answer
25
views
How to overlay only part of a video using ffmpeg or a similar tool (not the full frame)
I have two videos (let's say 1.mp4 and 2.mp4). I would like to overlay only the top-right quarter of 2.mp4 onto 1.mp4.
The output would be a single video with the content from 1.mp4 in the top left, ...
- 1
0
votes
0
answers
67
views
How to encode HEVC with alpha without a Mac?
I am trying to produce a file that Safari on Apple devices will play with alpha support. I don't actually have any Apple devices, though, and all of the instructions I've found for doing this suggest ...
- 101
0
votes
1
answer
202
views
How to create a video WITHOUT alpha, from a png sequence WITH alpha using ffmpeg
I have a sequence of pngs with alpha, and I'd like to encode to h264 without alpha, overlaid on black.
My usual command for image sequence to h264 is
ffmpeg -r 30 -i 'template %05d.png' -c:v libx264 -...
- 103
1
vote
1
answer
824
views
KDenlive, image sequence, and transparency/alpha/opacity of fades
This is probably the same question as https://www.reddit.com/r/kdenlive/comments/ik44o2/image_sequences_cutting_and_transparency/ ( and probably related to https://kdenlive.org/en/project/compositing-...
- 141
0
votes
1
answer
240
views
Suitable alternative to Quicktime RLE for alpha-containing non-cartoon videos?
I'm producing a product that involves a composition of several videos, over alpha layers, and there are surprisingly few options aside from image lists. Quicktime's RLE (Run-Length Encoding) codec ...
- 170
0
votes
1
answer
2k
views
ffmpeg to combine video + alpha video, transparency key with threshold
I have two corresponding video files. One is a regular video and the other is meant to be the alpha channel for that video. I wish to combine them, and use the alpha video to lay a transparency key ...
- 101
2
votes
1
answer
6k
views
Using a video as alpha mask for another on Davinci Resolve
Sorry I'm new, i can't find a tutorial to do this: i have a normal video and another one that i would like to use as an alpha mask to 'smooth borders' in davinci resolve, here is an example of my mask
...
- 21
2
votes
0
answers
35
views
Edges look wrong when compositing layer with blur and transparency
I'm trying to composite layers from an animation I made with Blender in After Effects. The problem I'm running into is that the motion-blurred edges are either receding, or becoming discolored, ...
- 21
4
votes
1
answer
17k
views
Creating transparent video from transparent png files using ffmpeg
I have a set of 300 transparent png files and I would like to create a transparent video file from them. I'm using the ffmpeg command as follows:
ffmpeg -f image2 -i anim.%04d.png -r 30 -vcodec png ...
- 143
0
votes
1
answer
602
views
How to convert a black and white video to a APNG file while setting a color as transparent?
I created a small video with threshold filter to get black and white pixels (no greyscale):
ffmpeg -y -i /dev/video0
-f lavfi -i color=0x606060:s=640x480
-f lavfi -i color=black:s=...
- 111
0
votes
1
answer
44
views
Audio not detected with Transparent Video Formats (Quicktime - PNG/QtAnimation- AAC/PCM)
On importing a transparent .mov file (Quicktime - PNG/QtAnimation- AAC/PCM) , the audio is not detected by the Videoeditors (Powerdirector17 < Davinci Resolve doesn't support the above format> )....
- 113
0
votes
0
answers
248
views
ffmpg (copy existing settings?) or crop a .mov with alpha and have it be open-able using Quicktime (not VLC)
How do you have ffmpeg copy all existing settings except the crop dimensions of a video file?
I've been struggling to crop an .mov with alpha channel (transparent video), so that it can be opened ...
- 101
0
votes
0
answers
2k
views
Importing Clip with Alpha Transparency into Resolve
Working on a video for a client with a third party animation company.
I need to figure out a file format they can export video with alpha transparency, that Resolve will import correctly.
Ordinarily I ...
1
vote
0
answers
113
views
After Effects doesn’t handle premultiplied images correctly
I’ve been told by various people in the industry that AFX doesn’t handle premultiplied images correctly and I’ve been able to verify this myself in my own pipeline. I’m just not sure if we are all ...
- 27
1
vote
2
answers
966
views
How to mask a mp4 video with another alpha mp4 video
A noob question. I have two mp4 video files. The first one is ordinary color video (right side).
The second one is transparency mask video (alpha), it's a mp4 video not an image (left side).
This ...
- 13
0
votes
1
answer
26
views
Does any software have the capability to create a mask/alpha value based on the volume of an audio channel
I'm looking for an automagical way to create a Google Hangouts effect, ie.
1. I have a number of files that are recordings of individual conversation members.
2. I want to put together the video ...
- 103
1
vote
1
answer
12k
views
Mask clip with transparency in DaVinci Resolve
Is it possible to use some combination of Color nodes and power windows to hide parts of an already partially transparent clip such as one whose frames might be made from transparent images like
?
I'...
- 13
0
votes
0
answers
421
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....
- 27
0
votes
1
answer
706
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=...
- 27
2
votes
1
answer
61k
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 ...
- 121
3
votes
1
answer
4k
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 ...
- 33
2
votes
0
answers
446
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 ...
- 121
0
votes
1
answer
1k
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 ...
- 81
0
votes
1
answer
492
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, ...
- 103
0
votes
1
answer
3k
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 ...
- 95
8
votes
3
answers
21k
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.
- 615
1
vote
0
answers
206
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 ...
- 111
2
votes
1
answer
112
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 ...
- 615
2
votes
1
answer
847
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 ...
- 1,004