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qiqian / webp

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cannot convert high resolution images #74

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago 
What steps will reproduce the problem?
1. Convert a high res image
2. Run "cwebp big.png -o big.webp"
3. Get an error message.

What is the expected output? What do you see instead?
Expected: Converted image
Instead: "Error! Cannot encode picture as WebP"

What version of the product are you using? On what operating system?
0.1.2

Please provide any additional information below.
Ive tried it first on a large jpg file, but created a small .png sample file so 
that this can be easily reproduced.

Original issue reported on code.google.com by martin.a...@gmail.com on 23 May 2011 at 8:05

Attachments:

GoogleCodeExporter commented 8 years ago 
Currently, the WebP format is limited to 16384 pixels in height or width. It 
cannot handle such large files yet.

Original comment by mikol...@google.com on 23 May 2011 at 3:39

GoogleCodeExporter commented 8 years ago 
idea (not for now): cwebp could automatically tile the source in case of large 
image.

Original comment by pascal.m...@gmail.com on 22 May 2012 at 7:39

GoogleCodeExporter commented 8 years ago 
The vp8 bitstream is limited to 16384 pixels, but the container isn't.
Could you make this work with lossless mode?

Original comment by fbarch...@google.com on 11 Jan 2013 at 3:01

GoogleCodeExporter commented 8 years ago 
for coherency reasons, lossless is also limited to 16384 pixel resolution.

Original comment by pascal.m...@gmail.com on 29 Jan 2014 at 9:18

GoogleCodeExporter commented 8 years ago 
Do all image algorithms have this 16382 pixel ratio cutoff? I was hoping that I 
can have a fallback to WebP if this exception occurs. Is it possible to some 
other algorithm to compress images which are greater than this limit?

Original comment by swaath...@gmail.com on 19 Mar 2015 at 8:35

GoogleCodeExporter commented 8 years ago 
JPEG allows for dimensions up to 65535x65535. PNG uses 31-bit resolution 
(2^31-1), but by default sets an upper bound of 1Mx1M [1].

[1] http://www.libpng.org/pub/png/libpng-manual.txt

Original comment by jz...@google.com on 20 Mar 2015 at 1:49

GoogleCodeExporter commented 8 years ago 
Great! Thanks.

Original comment by swaath...@gmail.com on 20 Mar 2015 at 2:43