Issue 359 in webp: why the command "webpmux -get frame 2 xxx.webp -o 2.webp" get a wrong size image?

[zhijie.l… via monorail]

Status: New
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 359 by zhijie.l...@gmail.com: why the command "webpmux -get frame 2 xxx.webp -o 2.webp" get a wrong size image?
https://bugs.chromium.org/p/webp/issues/detail?id=359

why the command "webpmux -get frame 2 xxx.webp -o 2.webp" get a wrong size image?

I expected that each frame has same size,just like the first frame.



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[jz… via monorail]

Comment #1 on issue 359 by jz...@google.com: why the command "webpmux -get frame 2 xxx.webp -o 2.webp" get a wrong size image?
https://bugs.chromium.org/p/webp/issues/detail?id=359#c1

webpmux extracts the raw frame and doesn't reconstruct the image as would happen in chrome for instance, you may want to try the newly added anim_dump utility [1].

[1] https://groups.google.com/a/webmproject.org/d/msg/webp-discuss/x1KhpfpMk0M/ebxw_uo1AwAJ

[pascal.m… via monorail]

Comment #2 on issue 359 by pascal.m...@gmail.com: why the command "webpmux -get frame 2 xxx.webp -o 2.webp" get a wrong size image?
https://bugs.chromium.org/p/webp/issues/detail?id=359#c2

indeed, in animation, each frame can update only a sub-rectangle of the full canvas.

Note for completeness, that there's a WebPAnimDecoder API in webp/demux.h to handle the animation's frame reconstruction.

See: https://developers.google.com/speed/webp/docs/container-api#webpanimdecoder_api

[jz… via monorail]

Updates:
Status: WontFix

Comment #3 on issue 359 by jz...@google.com: why the command "webpmux -get frame 2 xxx.webp -o 2.webp" get a wrong size image?
https://bugs.chromium.org/p/webp/issues/detail?id=359#c3

anim_dump should give you the fully reconstructed frames. Please file a new bug if there are any further issues.