NEW 216943
Chroma subsampling based on encode quality 
https://bugs.webkit.org/show_bug.cgi?id=216943
Summary Chroma subsampling based on encode quality
Micah
Reported 2020-09-24 14:36:28 PDT
Hi, One unresolved browser inconsistency in the Canvas API is how image encoding quality affects chroma subsampling. In Firefox, chroma subsampling is turned off at quality >= 0.9, allowing crisp images to be exported from Canvas at relatively small file sizes (e.g. quality 92%). Chrome & Webkit only disable chroma subsampling at quality == 1.0 (100%), meaning that it's impossible to export a crisp canvas as a JPEG without also exporting a massive image. I work at an online photo editor, and it means that we recommend Safari users save their images at 100% quality, and then use a different program to compress them (w/out chrome subsampling) before using them on a website. Other online photo editors bypass the browser altogether and load their own version of libjepg in WebAssembly. This seems a bit heavy-handed, and it'd be great if the browser default for Canvas produced images that were ready to use on the web. Chrome recently opened a WHATWG issue for this, and it'd be great to hear from Safari. https://github.com/whatwg/html/issues/5395 Improving this small corner of the web platform would make Safari a better platform for our users. Thanks!
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Radar WebKit Bug Importer
Comment 1 2020-09-27 10:06:46 PDT
<rdar://problem/69660091>
Micah
Comment 2 2021-01-28 14:58:08 PST
Any thoughts on this? It'd be great to hear from the Webkit team. Thanks!
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