JSON API does not share EXIF data for pictures in slideshow (GetInfoLabels)

[wutschel]

Bug report

Describe the bug

Here is a clear and concise description of what the problem is:

The JSON API of Kodi 21.0 ALPHA does not provide the expected response for picture EXIF data when requesting it via the following command:

{
    "jsonrpc": "2.0",
    "method": "XBMC.GetInfoLabels",
    "params": {"labels": ["Slideshow.Resolution",
                          "Slideshow.Process",
                          "Slideshow.Filename",
                          "Slideshow.CameraModel",
                          "Slideshow.CameraMake",
                          "Slideshow.EXIFTime",
                          "Slideshow.Aperture",
                          "Slideshow.ISOEquivalence",
                          "Slideshow.ExposureTime",
                          "Slideshow.Exposure",
                          "Slideshow.ExposureBias",
                          "Slideshow.MeteringMode",
                          "Slideshow.FocalLength"]
    },
    "id": 1
}

With 19.5 it works with the same image files.

Also, as per iOS Remote App use it does not work with Kodi 20.1, but with Kodi 17.6 (see https://forum.kodi.tv/showthread.php?tid=359717&pid=3155095#pid3155095).

Expected Behavior

Here is a clear and concise description of what was expected to happen:

The response provides results for all requested items, if present.

Actual Behavior

The response has empty strings as results for most of the fields. Only for camera make, camera model, filename, resolution and time there is a proper response.

Possible Fix

I cannot tell.

To Reproduce

Steps to reproduce the behavior:

1. Add images with EXIF data to playlist and start playing them.
2. Send JSON command as described above.
3. Review response.

Debuglog

The debuglog can be found here:

Screenshots

Here are some links or screenshots to help explain the problem:

Additional context or screenshots (if appropriate)

Here is some additional context or explanation that might help:

Your Environment

Used Operating system:

• Android

• iOS

• tvOS

• Linux

• macOS

• Windows

• Windows UWP

• Operating system version/name: Linux Mint 21.1

• Kodi version: 21.0 ALPHA

note: Once the issue is made we require you to update it with new information or Kodi versions should that be required.
Team Kodi will consider your problem report however, we will not make any promises the problem will be solved.

[rockrider69]

Hello,

+1 for solving this issue!

I can add that EXIF tag "UserComment" is not being reported correctly anymore, although it worked perfectly ok in Matrix or Leia when used in Slideshow labels for example.

$INFO[Slideshow.EXIFComment] : gives now an empty string despite it is not empty at all
$INFO[Slideshow.SlideComment] : supposed to be same as previous one, according to documentation, but now gives something weird about lavc software version. Not empty though if the documentation should be right...

Seems that mean more deeply broken stuff in EXIF tags management with Nexus ...

Note : This can be easily repoduced with the JSON API call as described in this issue, field name being Slideshow.EXIFComment.

[wutschel]

@enen92, I was looking at the code changes which added the out-of-boundary fixes from aosp. While doing this I stumbled across the use of sizeof(short) instead of using 2. Isn't sizeof(short) different for different compilers/platforms? Could this probably be related to the issues we're seeing (e.g. due to a compiler change)?

Code snippets from ExifParse.cpp:

const char* pos = (const char*)(ExifSection + sizeof(short));   // position data pointer after length field
...
pos += sizeof(short);

The Google code just uses 2 in these situations.

[wutschel]

Update: I could setup a Kodi build for Linux and look into the code changes related to the security / out-of-boundary checks which were made in 7e5f9fb and 00fec1d. None of them is causing the failing exif. Also changing sizeof(short) to 2 does not make a difference. The root cause is some other change.

[wutschel]

Thanks! Just compiled it and confirmed the EXIF data is readable again via JSON API.

[rockrider69]

@enen92 Thx a lot for proposing a fix on V19/V20 before the main rewriting, much appreciated !