Format error decoding Jpeg:

[Oreolek]

Tried to set wallpaper and failed:

0: Failed to read image "[…]/Wallpapers/classics/Hunters in the Snow (Winter) - Pieter Bruegel the Elder.jpg" needed for […]
1: Format error decoding Jpeg: "Parsing of the following header DAC is not supported,cannot continue"
2: "Parsing of the following header DAC is not supported,cannot continue"

Image is «Hunters in the Snow» downloaded from Wikipedia.

file output: JPEG image data, JFIF standard 1.01, resolution (DPI), density 300x300, segment length 16

The image works in swaybg btw.

[anoldguy]

For the record, I tried the following versions of the linked wallpaper, and could not reproduce with v1.2.1:

• 6819 × 4853 (Original file)
• 2560 x 1822
• 1280 x 911

I tried them separately, and together in a folder, and use wpaperctl next to rotate between them. My wpaperd daemon during that time:

» wpaperd -v
DEBUG [smithay_client_toolkit::registry] Bound new global [55] wl_output v4
DEBUG [smithay_client_toolkit::registry] Bound new global [58] wl_output v4
DEBUG [smithay_client_toolkit::registry] Bound new global [7] zxdg_output_manager_v1 v3
DEBUG [smithay_client_toolkit::shm] supported wl_shm format Xbgr8888
DEBUG [smithay_client_toolkit::shm] supported wl_shm format Xrgb8888
DEBUG [smithay_client_toolkit::shm] supported wl_shm format Abgr8888
DEBUG [smithay_client_toolkit::shm] supported wl_shm format Argb8888
^C

[danyspin97]

Hello @Oreolek , which is the version of wpaperd that you are using? If it works for @anoldguy (thanks for trying btw), then I thinkg it might work with the next tagged release.

[Oreolek]

i'm on 1.2.1 (as reported by --version) or 1.2.2 (as reported by pacman)

[Oreolek]

on the latest git it's causing a full crash instead of a warning:

The application panicked (crashed).
Message:  called `Result::unwrap()` on an `Err` value: Decoding(DecodingError { format: Exact(Jpeg), underlying: Some("Parsing of the following header `DAC` is not supported,cannot continue") })
Location: daemon/src/image_loader.rs:108

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
Rayon: detected unexpected panic; aborting
The application panicked (crashed).
Message:  called `Result::unwrap()` on an `Err` value: Decoding(DecodingError { format: Exact(Jpeg), underlying: Some("Parsing of the following header `DAC` is not supported,cannot continue") })
Location: daemon/src/image_loader.rs:108

[danyspin97]

Hi @Oreolek , I have tried with the master commit and it is working. Probably an update to the image crate fixed this issue. Thank you again for opening this issue!

[Oreolek]

yeah, I reinstalled wpaperd 1.3.0 and it's still crashing.

The application panicked (crashed).
Message:  called `Result::unwrap()` on an `Err` value: Decoding(DecodingError { format: Exact(Jpeg), underlying: Some("Parsing of the following header `DAC` is not supported,cannot continue") })
Location: daemon/src/image_loader.rs:108

Run with COLORBT_SHOW_HIDDEN=1 environment variable to disable frame filtering.
Rayon: detected unexpected panic; aborting

[danyspin97]

Can you please try deleting the image and downloading it again? Maybe it's corrupted.

[Oreolek]

It's not corrupted but I figured out the backstory:

I love classic paintings and got a lot of pics from sites like Wikipedia and Google Art Project. I used GIMP to cut them to 16:9; but the default JPEG export settings in GIMP use Distributed Arithmetic Coding (DAC). That's how I got a lot of DAC-encoded wallpapers.

I converted all of them to JFIF now with this script:

#!/usr/bin/php
<?php
foreach (new DirectoryIterator('.') as $file) {
  if($file->isDot()) continue;
  $filename = $file->getFilename();
  $ext = pathinfo($filename, PATHINFO_EXTENSION);
  $basename = pathinfo($filename, PATHINFO_BASENAME);
  if (!in_array($ext, ['jpg', 'jpeg'])) continue;
  $enc = _detectFileEncoding($filename);
  if ($enc !== 'Progressive DCT, arithmetic coding') continue;
  shell_exec('magick "'.$filename.'" "'.$basename.'.jfif"');
  shell_exec('mv "'.$filename.'" /tmp/');
}
function _detectFileEncoding($filepath) {
  $output = array();
  exec('exiftool "' . $filepath.'" | grep coding', $output);
  if (isset($output[0])){
    $ex = explode(':', $output[0]);
    return isset($ex[1]) ? trim($ex[1]) : null;
  }
  return null;
}