[wp-trac] [WordPress Trac] #62285: HDR AVIF is corrupt in the media library (encoded as SDR)

[WordPress Trac]

#62285: HDR AVIF is corrupt in the media library (encoded as SDR)
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 Reporter:  gregbenz      |       Owner:  adamsilverstein
     Type:  defect (bug)  |      Status:  assigned
 Priority:  normal        |   Milestone:  6.8
Component:  Media         |     Version:
 Severity:  normal        |  Resolution:
 Keywords:                |     Focuses:
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Comment (by gregbenz):

 @adamsilverstein Agreed, 8-bit was a safer choice in the past when most
 images had SDR luminance with Rec709 primaries. That no longer holds true.

 10-bit is the minimum for quality HDR, and in some cases 12-bit may be
 required to avoid banding. I believe preserving the bit depth up to
 12-bits is ideal to avoid risk of banding (visible quantization error).

 10-bit actually matters for some SDR (standard images) too. We can see
 banding in smooth gradients at 8-bits even in SDR, and wider gamuts
 further increase risk of quantization error (since the bits are spread
 across a wider range of values). So allowing preservation of 10-bit even
 for SDR is probably ideal, especially as encoding with Rec2020 primaries
 may become more common over time.

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Ticket URL: <https://core.trac.wordpress.org/ticket/62285#comment:6>
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