#9872: WebP vs PNG alpha
-------------------------------------+-------------------------------------
Reporter: Jozef | Owner: (none)
Chutka |
Type: defect | Status: new
Priority: normal | Component:
| undetermined
Version: unspecified | Resolution:
Keywords: scale alpha | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by Jozef Chutka):
The workaround is to create yet another `color=#ffffff00` and `overlay`
with the webp before the `scale` and the following filter graph. (`movie`
replaced by `color+movie+overlay`):
{{{
ALPHA PROBLEM:
ffmpeg -filter_complex
"color=white:200x200[b];movie=x.webp,scale=200:200,[b]overlay" -y out-
webp-scale.png
ALPHA FIXED:
ffmpeg -filter_complex
"color=white:200x200[b];color=color=#ffffff00:size=100x100[c];movie=x.webp,[c]overlay,scale=200:200,[b]overlay"
-y out-webp-scale-fix.png
scale-fix.png
}}}
This makes me think that there might some strange format used for webp
movie, which can not be enforced/changed by `format` filter, but can be
changed/fixed by `overlay`-ing it to artificial `color`
--
Ticket URL: <https://trac.ffmpeg.org/ticket/9872#comment:4>
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