Issue 292 in webp: Wrong transparency when converting from TIFF

[tal@cloudinary.com via Monorail]

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

New issue 292 by t...@cloudinary.com: Wrong transparency when converting from TIFF
https://bugs.chromium.org/p/webp/issues/detail?id=292

What steps will reproduce the problem?
1. cwebp old_logo.tiff -o old_logo.webp
2. open old_logo.webp in chrome

What is the expected output? What do you see instead?

WebP adds border around the arrows. The same border doesn't appear in the TIFF file, or when going through PNG


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

0.4.4/0.5.0 OS-X and linux.



Attachments:
old_logo.tiff 1.2 KB

--
You received this message because:
1. The project was configured to send all issue notifications to this address

You may adjust your notification preferences at:
https://bugs.chromium.org/hosting/settings

[jzern@google.com via Monorail]

Updates:
Status: Accepted

Comment #1 on issue 292 by jz...@google.com: Wrong transparency when converting from TIFF
https://bugs.chromium.org/p/webp/issues/detail?id=292#c1

Thanks for the report.
Given a quick look this seems to be related to the tiff decoder or webp wrapper for libtiff. Using ImageMagick to first go to png doesn't show the issue nor does using ffmpeg with libwebp encode support built in.
Are your 0.4.4/0.5.0 the release binaries or built locally? If they're local what version of libtiff do you have installed?

[tal@cloudinary.com via Monorail]

Comment #2 on issue 292 by t...@cloudinary.com: Wrong transparency when converting from TIFF
https://bugs.chromium.org/p/webp/issues/detail?id=292#c2

Using locally built cwebp with the following versions of libtiff:
OS-X - libtiff 4.0.6
Linux - libtiff 4.0.3-7ubuntu0.3

[jzern@google.com via Monorail]

Comment #3 on issue 292 by jz...@google.com: Wrong transparency when converting from TIFF
https://bugs.chromium.org/p/webp/issues/detail?id=292#c3

Judging by tifftopnm it looks like TIFFReadScanLine is returning different results for this image than TIFFReadRGBAImage/TIFFRGBAImageGet unless I'm missing something. I'll try to extract this to a simple test case.
I can't pull the latest libtiff source from cvs at the moment to see if there are any changes since 4.0.6 that might address this.

[jzern@google.com via Monorail]

Comment #4 on issue 292 by jz...@google.com: Wrong transparency when converting from TIFF
https://bugs.chromium.org/p/webp/issues/detail?id=292#c4

I filed a bug against libtiff:
http://bugzilla.maptools.org/show_bug.cgi?id=2537

[alfazi… via monorail]

Comment #5 on issue 292 by alfazi...@gmail.com: Wrong transparency when converting from TIFF
https://bugs.chromium.org/p/webp/issues/detail?id=292#c5

(No comment was entered for this change.)

Attachments:
index.html 0 bytes