Opened 7 weeks ago
#10901 new defect
HEVC with alpha to PNG does not maintain alpha
Reported by: | Jozef Chutka | Owned by: | |
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Priority: | normal | Component: | undetermined |
Version: | 6.1 | Keywords: | Hevc alpha |
Cc: | Blocked By: | ||
Blocking: | Reproduced by developer: | no | |
Analyzed by developer: | no |
Description
When converting hevc.mp4 with alpha into PNG, the alpha information is not respected, producing opaque PNG.
How to reproduce:
% ffmpeg -i hevc.mp4 -vframes 1 output.png
hevc.mp4 was created from source image with alpha channel and seems to have the alpha properly encoded:
ffmpeg -i source.png -vcodec hevc_videotoolbox -r 1 -t 1 -vtag hvc1 -alpha_quality 1 -y hevc.mp4
Following https://trac.ffmpeg.org/ticket/7965 which refers to https://patchwork.ffmpeg.org/project/ffmpeg/patch/tencent_5F1F4DA9CFDF5521A752B8C9161A4D23A007@qq.com/ it seems hevcdec has some kind of decoding support for alpha channel... is it hidden behind some command line flag?
Attachments (3)
Change History (3)
by , 7 weeks ago
Attachment: | source.png added |
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by , 7 weeks ago
by , 7 weeks ago
Attachment: | output.png added |
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