Issue 212 in webp: Simple API does not preserve EXIF metadata

[we...@googlecode.com]

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

New issue 212 by JamesMSo...@gmail.com: Simple API does not preserve EXIF
metadata
http://code.google.com/p/webp/issues/detail?id=212

I could have missed something simple but...

Using C# and dllimport

What steps will reproduce the problem?
1. Encode Image containing EXIF info using WebPEncodeBGRA.
2. Save image using File.WriteAllBytes.

What is the expected output? What do you see instead?
Image should contain EXIF metadata, image does not.

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

0.4.0 Windows 7/8.1

Attachments:
WebPFormat.cs 12.8 KB

--
You received this message because this project is configured to send all
issue notifications to this address.
You may adjust your notification preferences at:
https://code.google.com/hosting/settings

[we...@googlecode.com]

Comment #1 on issue 212 by jz...@google.com: Simple API does not preserve
EXIF metadata
http://code.google.com/p/webp/issues/detail?id=212

libwebp doesn't offer metadata manipulation, a separate pass using
libwebpmux [1] will be needed.

[1] https://developers.google.com/speed/webp/docs/container-api#mux_api

[james...@gmail.com]

Thanks for the extra info.

How come decoding using  WebPDecodeBGRAInto also decodes the metadata though?

I can read orientation info from an Image decoded using that method. It feels disjointed.

[james...@gmail.com]

Also, what type should I be returning using WebPMuxNew()? I can't seem to find a definition in the source.

[Pascal Massimino]

Hi James,

On Wed, Jun 25, 2014 at 2:38 AM, <james...@gmail.com> wrote:

Also, what type should I be returning using WebPMuxNew()? I can't seem to find a definition in the source.

It left undefined on purpose. This opaque WebPMux object gets only manipulated

through pointers, publicly.

 

On Wednesday, June 25, 2014 9:22:36 AM UTC+1, james...@gmail.com wrote:

Thanks for the extra info.

How come decoding using  WebPDecodeBGRAInto also decodes the metadata though?

hmm... this function only decodes raw pixels from the compressed bitstream

and doesn't parse any metadata.

 

I can read orientation info from an Image decoded using that method. It feels disjointed.

On Wednesday, June 25, 2014 1:58:44 AM UTC+1, we...@googlecode.com wrote:

Comment #1 on issue 212 by jz...@google.com: Simple API does not preserve  
EXIF metadata
http://code.google.com/p/webp/issues/detail?id=212

libwebp doesn't offer metadata manipulation, a separate pass using  
libwebpmux [1] will be needed.

[1] https://developers.google.com/speed/webp/docs/container-api#mux_api

--
You received this message because this project is configured to send all  
issue notifications to this address.
You may adjust your notification preferences at:
https://code.google.com/hosting/settings

--
You received this message because you are subscribed to the Google Groups "WebP Discussion" group.
To unsubscribe from this group and stop receiving emails from it, send an email to webp-discuss...@webmproject.org.
To post to this group, send email to webp-d...@webmproject.org.
Visit this group at http://groups.google.com/a/webmproject.org/group/webp-discuss/.
For more options, visit https://groups.google.com/a/webmproject.org/d/optout.

[james...@gmail.com]

You're correct, sorry. I'd previously loaded the EXIF data though other means. I was converting the file to webp.

I'm at a loss now. Which methods should I invoke? There are no examples for C# 

[diosmede...@gmail.com]

I can not download your attachment.
If you attach your actual code with comments, I will try to help you.

[james...@gmail.com]

Thanks that would be really awesome,

I think it's probably best if I link to my github repo. That way you can see the code in context.

https://github.com/JimBobSquarePants/ImageProcessor/blob/V2/src/ImageProcessor/Imaging/Formats/WebPFormat.cs

It's part of a much bigger project. 

Cheers!

James

[we...@googlecode.com]

Updates:
Status: WontFix
Labels: -Type-Defect Type-Enhancement

Comment #2 on issue 212 by jz...@google.com: Simple API does not preserve
EXIF metadata
http://code.google.com/p/webp/issues/detail?id=212

I'm marking this as an enhancement for tracking, but closing it as there
aren't any plans to add this functionality to libwebp currently.