[Webkit-unassigned] [Bug 220317] New: Certain webp files can't be displayed

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=220317

            Bug ID: 220317
           Summary: Certain webp files can't be displayed
           Product: WebKit
           Version: Safari 14
          Hardware: All
                OS: macOS 11
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Images
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: radek.sery at gmail.com

Created attachment 416983

  --> https://bugs.webkit.org/attachment.cgi?id=416983&action=review

Source file for conversion

Hi,
we have discovered that some webp images do not display properly (they don't display at all) in Safari 14 on macOS 11. In other browsers, these webp images render just fine, but Safari will only display placeholder image. The webp image itself can't be open in native macOS app for images either.

In the attachments, you can see two webp images, both converted with cwebp 1.1.0 (latest) binary utility. First one with quality=80, second one with quality=85. First one can't be displayed, the second one can be. There's also source png file attached.

This is the command used as well as the verbose output from cwebp utility for both conversions:

zipper:~$ cwebp -q 80 4942.png -o 4942-80.webp -v
Time to read input: 0.024s
Saving file '4942-80.webp'
Time to encode picture: 0.076s
File:      4942.png
Dimension: 1400 x 1110 (with alpha)
Output:    6132 bytes Y-U-V-All-PSNR 54.21 62.26 63.26   55.67 dB
           (0.03 bpp)
block count:  intra4:        302  (4.90%)
              intra16:      5858  (95.10%)
              skipped:      5498  (89.25%)
bytes used:  header:             85  (1.4%)
             mode-partition:   3507  (57.2%)
             transparency:       91 (99.0 dB)
 Residuals bytes  |segment 1|segment 2|segment 3|segment 4|  total
    macroblocks:  |       0%|       1%|       2%|      96%|    6160
      quantizer:  |      27 |      27 |      26 |      19 |
   filter level:  |       8 |       6 |      17 |      21 |
Lossless-alpha compressed size: 90 bytes
  * Header size: 19 bytes, image data size: 71
  * Lossless features used: PALETTE
  * Precision Bits: histogram=5 transform=5 cache=0
  * Palette size:   2



zipper:~$ cwebp -q 85 4942.png -o 4942-85.webp -v
Time to read input: 0.023s
Saving file '4942-85.webp'
Time to encode picture: 0.076s
File:      4942.png
Dimension: 1400 x 1110 (with alpha)
Output:    7208 bytes Y-U-V-All-PSNR 55.04 64.82 64.39   56.57 dB
           (0.04 bpp)
block count:  intra4:        400  (6.49%)
              intra16:      5760  (93.51%)
              skipped:      5269  (85.54%)
bytes used:  header:            104  (1.4%)
             mode-partition:   3712  (51.5%)
             transparency:       91 (99.0 dB)
 Residuals bytes  |segment 1|segment 2|segment 3|segment 4|  total
    macroblocks:  |       0%|       1%|       2%|      96%|    6160
      quantizer:  |      20 |      20 |      18 |      13 |
   filter level:  |       7 |       5 |       8 |      13 |
Lossless-alpha compressed size: 90 bytes
  * Header size: 19 bytes, image data size: 71
  * Lossless features used: PALETTE
  * Precision Bits: histogram=5 transform=5 cache=0
  * Palette size:   2

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-unassigned/attachments/20210105/cfa900ac/attachment-0001.htm>