Animated AVIF in some Safari versions return a black background instead of transparency

Seeing an issue in some versions of Safari (16.6, 18.3, 18.5) where an APNG converted to AVIF does not support transparency. Instead of a transparent background, the background is filled with black.

For context: Original image: https://vuaws2024.imgix.net/elephant.png (has animation as APNG)

As an AVIF: https://vuaws2024.imgix.net/elephant.png?fm=avif

  • has transparency and animation in Chrome 138
  • animation works, has a black background on Safari 16.6, 18.3, 18.5
  • works as expected in Safari 17.5 with transparency and animation
Animated AVIF in some Safari versions return a black background instead of transparency
 
 
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