[wp-trac] [WordPress Trac] #62365: HEIC upload conversion mappings may conflict with `image_editor_output_format` overrides

[WordPress Trac]

#62365: HEIC upload conversion mappings may conflict with
`image_editor_output_format` overrides
--------------------------------------------+------------------------------
 Reporter:  ironprogrammer                  |       Owner:  adamsilverstein
     Type:  defect (bug)                    |      Status:  assigned
 Priority:  normal                          |   Milestone:  6.8
Component:  Media                           |     Version:  6.7
 Severity:  normal                          |  Resolution:
 Keywords:  has-testing-info needs-refresh  |     Focuses:
--------------------------------------------+------------------------------
Changes (by SirLouen):

 * keywords:  has-patch has-unit-tests => has-testing-info needs-refresh


Comment:

 == Test Report
 === Description
 This report can't validate that the patch works as expected.

 Patch tested: https://github.com/WordPress/wordpress-
 develop/pull/7815.diff

 === Environment
 - WordPress: 6.8-alpha-59274-src
 - PHP: 8.2.28
 - Server: nginx/1.27.4
 - Database: mysqli (Server: 8.4.4 / Client: mysqlnd 8.2.28)
 - Browser: Chrome 134.0.0.0
 - OS: Windows 10/11
 - Theme: Twenty Twenty-Five 1.0
 - MU Plugins: None activated
 - Plugins:
   * Test Reports 1.2.0

 === Expected Results

 - The expected results is uploading a HEIC image and having all images
 converted to AVIF in multiple sizes

 === Testing Procedure

 1. Add this snippet to functions.php a plugin, or wherever it can be
 loaded

 {{{#!php
 function filter_image_editor_output_format( $formats ) {
         $formats['image/heic'] = 'image/avif';
         return $formats;
 }
 add_filter( 'image_editor_output_format',
 'filter_image_editor_output_format' );
 }}}

 2. Upload an image in HEIC format. Example: https://heic.digital/download-
 sample/classic-car.heic
 3. Go to the uploads directory and check for all the converted images.

 === Actual Results

 ==== Without patch
 - Images are converted to JPG instead of AVIF as expected, as this is the
 default behaviour

 {{{
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# ls classic-car*
 classic-car-1152x1536.jpg  classic-car-1536x2048.jpg  classic-car-
 768x1024.jpg  classic-car.heic
 classic-car-150x150.jpg    classic-car-225x300.jpg    classic-car-
 scaled.jpg
 }}}

 ==== With patch
 - ❌ The patch is not fully working as expected
 - Some images are converted to AVIF, but not all
 - The conversion takes too long: https://i.imgur.com/qRHZaCr.png
 - And after a while it fails: https://i.imgur.com/oTNp8VR.png

 In the end, not all image sizes are generated + one is corrupted:
 {{{
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# ls classic-car*
 classic-car-1152x1536.avif  classic-car-225x300.avif   classic-car-
 scaled.avif
 classic-car-150x150.avif    classic-car-768x1024.avif  classic-car.heic
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# file --mime-
 type classic-car.heic
 classic-car.heic: image/heic
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# file --mime-
 type classic-car-scaled.avif
 classic-car-scaled.avif: application/octet-stream
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# file --mime-
 type classic-car-150x150.avif
 classic-car-150x150.avif: application/octet-stream
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# file --mime-
 type classic-car-225x300.avif
 classic-car-225x300.avif: application/octet-stream
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# file --mime-
 type classic-car-768x1024.avif
 classic-car-768x1024.avif: application/octet-stream
 root at bb89abdaa4e7:/var/www/src/wp-content/uploads/2025/03# file --mime-
 type classic-car-1152x1536.avif
 classic-car-1152x1536.avif: inode/x-empty (CORRUPTED IMAGE)
 }}}

 I'm testing with regular parameters from the `wordpress-develop` docker.
 Maybe increasing the PHP execution time could lead to a full conversion.
 Anyway, I'm not sure if taking that long is worth the deal, maybe this is
 because of the chained conversions? This leads to further discussion.

 === Additional Notes and Further Discussion
 - I'm not completely aware of how the conversion is being done behind the
 scene. Judging from the conversation, it seems that there is a double
 conversion in a chain: First from HEIC to JPG (default) and then from JPG
 to AVIF (with thanks to the filter hook upgrade).

 - Still, I'm not if it's possible to do a straight conversion from HEIC to
 AVIF. The suggestion is that this type of conversion should be left to
 plugins, not native to WP.

 - I'm assuming that @adamsilverstein suggests leaving open this ticket
 just in case someone takes the time to upgrade the conversion system to
 avoid a chained conversion?

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/62365#comment:15>
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