How to get the EXIF data from a file using C#

StackOverflow https://stackoverflow.com/questions/9123026

  •  22-04-2021
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Question

I would like to write a small program in C# which goes through my jpeg photos and, for example, sorts them into dated folders (using MY dating conventions, dammit...).

Does anyone know a relatively easy way to get at the EXIF data such as Date And Time or Exposure programatically? Thanks!

Était-ce utile?

La solution

Check out this metadata extractor. It is written in Java but has also been ported to C#. I have used the Java version to write a small utility to rename my jpeg files based on the date and model tags. Very easy to use.

EDIT metadata-extractor supports .NET too. It's a very fast and simple library for accessing metadata from images and videos.

It fully supports Exif, as well as IPTC, XMP and many other types of metadata from file types including JPEG, PNG, GIF, PNG, ICO, WebP, PSD, ...

var directories = ImageMetadataReader.ReadMetadata(imagePath);

// print out all metadata
foreach (var directory in directories)
foreach (var tag in directory.Tags)
    Console.WriteLine($"{directory.Name} - {tag.Name} = {tag.Description}");

// access the date time
var subIfdDirectory = directories.OfType<ExifSubIfdDirectory>().FirstOrDefault();
var dateTime = subIfdDirectory?.GetDateTime(ExifDirectoryBase.TagDateTime);

It's available via NuGet and the code's on GitHub.

Autres conseils

As suggested, you can use some 3rd party library, or do it manually (which is not that much work), but the simplest and the most flexible is to perhaps use the built-in functionality in .NET. For more see:

I say "it’s the most flexible" because .NET does not try to interpret or coalesce the data in any way. For each EXIF you basically get an array of bytes. This may be good or bad depending on how much control you actually want.

Also, I should point out that the property list does not in fact directly correspond to the EXIF values. EXIF itself is stored in multiple tables with overlapping ID’s, but .NET puts everything in one list and redefines ID’s of some items. But as long as you don’t care about the precise EXIF ID’s, you should be fine with the .NET mapping.

Edit: It's possible to do it without loading the full image following this answer: https://stackoverflow.com/a/552642/2097240

Here is a link to another similar SO question, which has an answer pointing to this good article on "Reading, writing and photo metadata" in .Net.

You can use TagLib# which is used by applications such as F-Spot. Besides Exif, it will read a good amount of metadata formats for image, audio and video.

I also like ExifUtils API but it is buggy and is not actively developed.

Image class has PropertyItems and PropertyIdList properties. You can use them.

Getting EXIF data from a JPEG image involves:

  1. Seeking to the JPEG markers which mentions the beginning of the EXIF data,. e.g. normally oxFFE1 is the marker inserted while encoding EXIF data, which is a APPlication segment, where EXIF data goes.
  2. Parse all the data from say 0xFFE1 to 0xFFE2 . This data would be stream of bytes, in the JPEG encoded file.
  3. ASCII equivalent of these bytes would contain various information related to Image Date, Camera Model Name, Exposure etc...

The command line tool ExifTool by Phil Harvey works with dozens of images formats - including plenty of proprietary RAW formats - and can manipulate a variety of metadata formats including EXIF, GPS, IPTC, XMP, JFIF.

Very easy to use, lightweight, impressive application.

Recently, I used this .NET Metadata API. I have also written a blog post about it, that shows reading, updating, and removing the EXIF data from images using C#.

using (Metadata metadata = new Metadata("image.jpg"))
{
    IExif root = metadata.GetRootPackage() as IExif;
    if (root != null && root.ExifPackage != null)
    {
        Console.WriteLine(root.ExifPackage.DateTime);
     }
}
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