Seeing NotFound on all image types

[yaneury]

Hi! I'm trying the sample code to output the EXIF metadata for all images in a directory:

for entry in std::fs::read_dir(root).unwrap() {
    let file = std::fs::File::open(entry.unwrap().path()).unwrap();
    println!("File: {:?}", file);
    let mut bufreader = std::io::BufReader::new(&file);
    let exif = exif::Reader::new().read_from_container(&mut bufreader).unwrap();
    for f in exif.fields() {
        println!("{} {} {}",
                f.tag, f.ifd_num, f.display_value().with_unit(&exif));
    }
}

But the call to read_from_container is failing for all images I throw at it, e.g. jpeg, png. These are files that are confirmed to have EXIF metadata through identify -verbose <filename>

The error I'm seeing is:

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: NotFound("JPEG")', src/main.rs:19:80

Any idea what I'm doing wrong?

[kamadak]

Could you provide an image file that ImageMagick says has Exif but this library says has no Exif?

My super wild guess is that the first file returned by read_dir does not really have Exif data, and your sample code stops by unwrap at that point and does not proceed to the remaining files.

[yaneury]

It occurred with different types of images. Here's a sample one

[yaneury]

And the output from ImageMagick:

❯ identify -verbose index.jpeg              
Image:
  Filename: index.jpeg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 225x225+0+0
  Units: Undefined
  Colorspace: sRGB
  Type: TrueColor
  Base type: Undefined
  Endianness: Undefined
  Depth: 8-bit
  Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
  Channel statistics:
    Pixels: 50625
    Red:
      min: 28  (0.109804)
      max: 255 (1)
      mean: 241.801 (0.948238)
      standard deviation: 24.7243 (0.096958)
      kurtosis: 2.26448
      skewness: -1.76917
      entropy: 0.382322
    Green:
      min: 16  (0.0627451)
      max: 255 (1)
      mean: 238.729 (0.936193)
      standard deviation: 32.4425 (0.127225)
      kurtosis: 6.62594
      skewness: -2.41441
      entropy: 0.388998
    Blue:
      min: 0  (0)
      max: 255 (1)
      mean: 234.622 (0.920088)
      standard deviation: 39.7632 (0.155934)
      kurtosis: 6.38241
      skewness: -2.37785
      entropy: 0.404171
  Image statistics:
    Overall:
      min: 0  (0)
      max: 255 (1)
      mean: 238.384 (0.93484)
      standard deviation: 32.31 (0.126706)
      kurtosis: 7.66558
      skewness: -2.49239
      entropy: 0.39183
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Background color: white
  Border color: srgb(223,223,223)
  Matte color: grey74
  Transparent color: black
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 225x225+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 74
  Orientation: Undefined
  Properties:
    date:create: 2022-11-14T20:27:08+00:00
    date:modify: 2022-11-14T20:27:08+00:00
    jpeg:colorspace: 2
    jpeg:sampling-factor: 2x2,1x1,1x1
    signature: 493881774b51a76ac07c3c14c78e20c31cb50a2c307ec95b0c5909cdba72cfaf
  Artifacts:
    filename: index.jpeg
    verbose: true
  Tainted: False
  Filesize: 2798B
  Number pixels: 50625
  Pixels per second: 114.392MB
  User time: 0.000u
  Elapsed time: 0:01.000
  Version: ImageMagick 6.9.11-60 Q16 x86_64 2021-01-25 https://imagemagick.org

[kamadak]

That sample does not have Exif data.

ImageMagick will output "Profiles-exif: x bytes" line for an image with Exif:

Image:
  Filename: sample_with_exif.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
...
  Profiles:
    Profile-exif: 10362 bytes                   <-- See this line
  Properties:
    date:create: 2014-09-02T20:54:50+00:00
    date:modify: 2014-09-02T20:54:50+00:00
    date:timestamp: 2022-11-15T01:28:38+00:00
    exif:ApertureValue: 390/100                 <-- Exif attributes are printed like these
    exif:BrightnessValue: 199/100
    exif:ColorSpace: 1
    exif:ComponentsConfiguration: ....
    exif:CompressedBitsPerPixel: 32/10
    exif:Copyright:
    exif:CustomRendered: 0
    exif:DateTime: 2014:09:02 21:47:18
    exif:DateTimeDigitized: 2014:09:02 21:47:18
    exif:DateTimeOriginal: 2014:09:02 21:47:18
    exif:ExifOffset: 294
    exif:ExifVersion: 0220
...
  Version: ImageMagick 7.1.0-47 Q8 x64 47c6f10:20220827 https://imagemagick.org

[yaneury]

Oh my mistake. Didn't know where that metadata was coming from. Good catch!