Use EXIF taken date as sorting date for photos [$200]

[oparoz]

From @jancborchardt on July 20, 2015 17:2

Use-case: Doing a trip with friends and multiple people take photos. Afterwards when you move them all in the same folder from the different devices, the sorting is off. It’s not based off the EXIF date but instead the modified date.

We should sort photos where there is an EXIF date present by that date. @oparoz

Ref owncloud/gallery#101

Pre-requirements

• Collect EXIF/XMP/IPTC data (Create an app to manage the meta data stored in media files owncloud/gallery#550)

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Copied from original issue: owncloud/gallery#221

[oparoz]

Agreed, but for this to work well, data should be extracted and indexed in the DB at upload time, otherwise it will slow down all operations since each file would have to be opened before we're able to get the list of files.

[oparoz]

From @jancborchardt on July 20, 2015 17:26

Maybe this is something for core then? The sorting should be right in the Files app already as well. cc @schiesbn @DeepDiver1975

[oparoz]

Yes, I think the upload mechanism could do with adding more data to the FileInfo object attached to each file (dimensions, exif data object), but I'm not sure the Files app would benefit from it, even in thumbnails view. That kind of sorting works best for media files.

Also, I want to add the possibility of letting users add the missing data to other files so that they can mix PSD and JPEG files per example, but I'm not sure it's something people are going to do often (both adding data and mixing content).

A first step could be to introduce another of those settings which lets users who need the feature enable it despite the slowdowns. That way, it wouldn't affect the app for all the other users.
The main downside is that there is no easy way of caching the information between sessions...

[oparoz]

From @patman15 on September 21, 2015 19:55

I just made in one evening a prototype implementation on v14.0.0 that adds the exif time to the file properties and allows sorting. Since I'm new to owncloud and galleryplus, I'm pretty sure it's not the best, but it works. Also I read using the file system might slow things down. Nevertheless, if there is interest, I could provide the patch.

[oparoz]

From @jancborchardt on September 22, 2015 7:58

@patman15 hey, cool! :) Of course there’s interest – it would be very nice if you can open a pull request here with the patch.

[oparoz]

@patman15 - Thanks for your work :). Please submit a PR and we'll know more about what you've done.

The actual EXIF parsing code is not really the problem here, but the fact that not all images contain that information and that if we don't store it, then we need to parse the files every time and it will be very slow for external storages.

Without a new sorting button (!), the sort by date button will mix together different types of information. We need to think about the best solution for users here. The behaviour needs to be predictable.
Let's list available options and outcomes.

[oparoz]

From @patman15 on September 22, 2015 14:21

Ok, sure I'll submit a PR soon.

Button is drawn and added, logic is enhanced from two to three sort types. I'm still thinking about how to handle files without EXIF. Either use the modification time as fallback for those cases or for the complete album or disable the button if not all files are with EXIF.

Regarding speed: I read about the issue before I started. Since I'm new to OC programming I couldn't figure out yet where file (content) is actually accessed. Thumbnail generation might be one good point to add the parsing. Currently, I put it into the searchmediaserivce.php and there is still an enhancement by switching to stream access. Nevertheless, yes, it loads every time you open the folder.

[oparoz]

Thumbnail generation might be one good point to add the parsing

Yes and that's done in core. There are 2 alternatives:

• add a hook and to collect the information in our own DB table every time a file is uploaded, see Browser bar always displays on mobile device during slideshow. #101
• create an app just for that as the information could be useful for other apps

I'm in favour of the 2nd option as it offers much more flexibility and zero dependency on core.

Then in Gallery, we could have an ExifService (or use the one in the Exif app even if it's frown upon) which would collect the needed information.

[oparoz]

From @patman15 on September 23, 2015 12:30

@oparoz So, PR is there, if you want to have a look. I still have to fix a few issues to increase quality.

I just tested performance on a directory with only jpg images (worst case as other mime types do not impact performance). On the directory containing 1429 images my (very small home) server took 3.9s for scanning while the patch increases the time to 6.4s (+64%). I still have a few performance increasing options available, but it won't help too much. Nevertheless, I'm quite happy with it for my personal use case.

If you could give me some more infos on how your second option should look like or whether I should try to extend the core, I would be happy to invest some more time. Just let me know if I should finalize the current patch as an intermediate solution or directly focus on a more mature solution.