Questions tagged [alpha-channel]
The alpha-channel tag has no usage guidance.
35
questions
46
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get pixel alpha value
Given a pixel in an image imported from a png file, how can I get the alpha value of the pixel with the GIMP? If this is not possible, what software can I use to achieve this (OS: Linux)?
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9
answers
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Extracting the layer transparency into an editable layer mask in Photoshop
Is there any simple way to extract the "baked in" transparency in a layer and turn it into a layer mask in Photoshop? To take a simple example: Let's say that I paint a few strokes with a semi-...
- 145
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votes
3
answers
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Turn grayscale into alpha channel in Paint.net
I have a PNG image that has many shades of gray and no transparency:
I would like to turn the grayscale into an alpha channel in Paint.net, so that the parts that are completely white would become ...
- 2,569
9
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1
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How do I add a background to a transparent png in gimp?
I have a png file with a transparent background. I would like to add a non-transparent background from a jpg. I have tried:
Open the transparent png file. I see the picture with the checkerboard ...
- 257
8
votes
3
answers
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Point sample opacity/alpha in Adobe Photoshop?
I opened a PNG containing an alpha channel in Photoshop and wanted to get the opacity / alpha of a given point in the PNG file, so that I could match that opacity in a new photoshop layer. How can I ...
- 9,747
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6
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Is there any way to save a PNG-8 file with Alpha Transparency in Photoshop?
I recently discovered something that I previous thought was impossible: PNG-8 files can store Alpha Transparency in the same way as PNG-32 files can. Not Indexed Transparency (like GIFs), but full on ...
- 4,464
6
votes
1
answer
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ffmpeg: change alpha channel of a showwaves filter
I've been trying to figure this issue out for a few hours and I can't seem to find any solution.
I'm creating a video from an .mp3 and some images with the following command
fmpeg.exe -y -i temp\...
- 136
3
votes
1
answer
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Lossless VP9 Webm Encoding of PNG Sequence with Alpha in FFmpeg
I'm trying to encode a sequence of 32-bit 8bpc PNG images (RGB with an alpha channel) using the lossless VP9 codec with ffmpeg; specifically:
ffmpeg -framerate 60 -i out%04d.png -c:v libvpx-vp9 -...
- 1,560
3
votes
1
answer
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Lossless Video Codec supporting Alpha Channels
Suppose I have a sequence of PNG image files which may or may not contain an alpha channel (assume those that do have an alpha channel actually utilize it). While PNG files themselves have their own ...
- 1,560
3
votes
1
answer
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overlay a sample video with alpha channel over another video in gstreamer
I want to play 2 video files using a GStreamer pipeline on my screen. The first video is without an embedded alpha channel and I want the second video with an embedded alpha channel to be overlaid ...
- 249
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3
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ffmpeg -- How do I overlay a PNG over another PNG?
I have PNG A with alpha layer, which I want to overlay on top of another PNG B. How do I do that with ffmpeg?
I tried ffmpeg -i A.png -i B -filter_complex "[0:v][1:v] overlay=0:0" out.png, but I ...
- 123
2
votes
1
answer
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Is it possible to compress alpha and RGB channels of PNG sequence separately with FFmpeg?
Suppose I have a sequence of 32-bit (RGBa) PNG files. Is it possible to compress the RGB channel with one codec and the alpha channel with another? For example, if I had the RGB and alpha as separate ...
- 1,560
2
votes
1
answer
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How do i convert a transparent .mov-file to an mp4 file overlayed on a background-image using FFMPEG
I'm trying to convert a mov file with the following specs:
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mov':
Metadata:
major_brand : qt
minor_version : 537199360
...
- 143
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votes
2
answers
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How can you test a video with alpha channel before merging it with another video?
I am working on videos with alpha channel to be merged with a background video at a given position (for instance, [100,100]) . You can accomplish this by using:
ffmpeg -i BACK -i OVER -...
- 1,531
2
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1
answer
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Alpha plugin in GStreamer not working
I'm trying to compose two videos, and I'm using the alpha plug-in to make the white color transparent.
To test the alpha plug-in I'm creating the pipeline with gst-launch.
The first test I done was:
...
2
votes
1
answer
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Using ffmpeg to create a video from a sequence of TGA images, with a depth of field blur effect sourced from the TGA's alpha channel
I'm working on turning a sequence of TGA images into a video using ffmpeg. I want the video to have a depth of field blur effect. The alpha channel of each TGA contains a depth-mask, where black=...
- 21
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votes
1
answer
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Keep alpha transparency in indexed PNG from Fireworks when batch resizing using convert (ImageMagick)
I have a special case where I'm using alpha transparency in indexed PNGs from Fireworks to keep the file size of PNG's in an iOS game down. (That is, indexed colors like an 8bit PNG but alpha ...
- 810
2
votes
1
answer
182
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Integrating ffmpeg4 with Pyglet. What is correct method to identify streams with alpha?
We're trying to interate ffmpeg4 with Pyglet.
Its all going very well but we have one issue:
If a VP9 (or VP8) file is created using ffmpeg4, from png files with alphas, we get a video file (webm) ...
- 121
1
vote
0
answers
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ffmpeg stuck on last couple of frames during alphamerge
I'm trying to put alpha channel on an mp4 file, using an alpha file that I have previously extracted. The command that I'm using with some tuning flags is this:
ffmpeg -hide_banner -i video.mp4 -i ...
- 11
1
vote
2
answers
4k
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Is it possible to overlay video with alpha channel over the desktop in real time (Windows)?
I'm going to run a pen & paper RPG game and one of my players will participate via Skype. To make his appearance more immersive, I would like to cast some sort of futuristic HUD over the video ...
- 13
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vote
0
answers
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opensource vp6a encoding
I am looking for a way to encode a movie with vp6a. I was hoping I would be able to do this with ffmpeg using this command:
ffmpeg -i test.flv -loop 1 -i bg.tga -vcodec vp6a -vframes 1037 -b:v 1024k -...
- 11
1
vote
1
answer
442
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How to combine multiple similar images with "holes" into one good one?
Suppose you have multiple photos of the same object (from slightly different angles), each have some obstacles in foreground.
You added an alpha channel to each picture and "erased" the obstacle (...
- 17.2k
1
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0
answers
2k
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.MOV video compressed with PNG has no alpha channel
I have a QuickTime file .mov with alpha channel compressed with PNG codec. What I need is to create smaller version of this file using ffmpeg. Everything works except new mov has no alpha (Adobe After ...
- 21
1
vote
0
answers
286
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Render Video as png with Alpha
I have pixel art that I want to put in an animated png. I animated it in the timeline, but when I rendered it into a series of pngs, It has no partial transparency. Anyone know how to solve this?
- 249
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1
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Convert TIFF with Alpha Channel to PNG?
I have a TIFF File that has a blue background and an Alpha Channel. I would like to save a PNG File which has the blue background transparent, using the Alpha Channel (because some pixels are not ...
- 3,101
0
votes
1
answer
5k
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Transparent Video (RGB+Alpha) in PowerPoint
I am able to export a transparent-background video in After Effects - AVI with RGB+Alpha. It was of a man talking with a green screen background.
However, once I import it to PowerPoint, a black ...
- 125
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votes
1
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Alphamerge filter only works on first frame
I am trying to implement blur filter over specific non rectangle object, I have mask and sample video but the issue is that alphamerge result of first frame of video is applied to the whole video(Like ...
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1
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466
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Convert bmp to png and black colors to alpha
I exported some sprites from the game Half-Life; however, they seem to have tones of black instead of the alpha channel. For example:
How do I convert the black colors into alpha/transparency?
0
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2
answers
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How can I convert the color in this button into an alpha transparency so that any background will show through, changing the color of the button?
The button has a layer in it that has a bevel/emboss filter on it. I'm stumped.
Here's the PSD that I'm trying to convert.
- 777
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votes
1
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ARGB in Adobe Illustrator
I need to create some icons and my client's requirements are (A: 0, R:255, G: 255, B: 255) for the background.
I'm working on Adobe Illustrator, how do I change the Alpha?
When the background is ...
- 1
0
votes
1
answer
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ffmpeg merge videos including one with alpha transparency with mp3 audio
I have two video tracks (one with alpha transparency and both without audio) and an audio file, I need to put them all together with the same beginning.
so:
I only managed to mix the two videos ...
- 51
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votes
1
answer
443
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How to get exact alpha value in Photoshop
I need to know the exact alpha value of a pixel in Photoshop. I tried using the answer in this question (Determine pixel alpha value in photoshop), but that gives me an opacity percentage such as 27%, ...
user169819
0
votes
0
answers
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Apply depth of field blur effect from a grayscale video using ffmpeg [duplicate]
I have two videos.
One is a normal video, the other is a grayscale video.
Supposedly, merging the videos I can have a video with a depth of field blur effect.
I wish to know how I could do it using ...
0
votes
0
answers
174
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How to concatenate different sized videos and then overlay with transparency on a background in ffmpeg?
I have multiple videos that are different sized, and I needed to concatenate them and then put the finished concatenated result on top of a 1080p background. However, the only way I can currently do ...
- 11
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1
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How do I discard transparency channel when encoding files with bpgenc?
Sometimes png pictures contain redundant alpha channel. While this is usually not an issue, for libbpg it triggers more complicated mode which is not compatible with fast x265 encoding or with ...
- 17.2k