1890872 - Match Chrome behavior when it comes to accepting images as LCP elements

Status: NEW

(Core :: DOM: Performance APIs, enhancement, P3)

Description

[Bas Schouten (:bas.schouten)]

Chrome has been looking at how to reduce 'LCP cheating'. One of the things they were doing is checking the entropy of the image and if it's too low it doesn't qualify. The 'entropy' check, when I talked to them was just looking at the compressed file size. This shouldn't be too difficult for us to do as well. See also: https://chromium.googlesource.com/chromium/src/+/refs/heads/main/docs/speed/metrics_changelog/2023_04_lcp.md

Comment 1

[Sean Feng [:sefeng211]]

Attachment: Bug 1890872 - Implement LCP entropy r=emilio

Comment 2

[BugBot [:suhaib / :marco]]

There is an r+ patch which didn't land and no activity in this bug for 2 weeks.
:sefeng, could you have a look please?
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Comment 3

[Emilio Cobos Álvarez [:emilio]]

See the discussion in the patch.

Comment 4

[Dave Hunt [:davehunt] [he/him] ⌚BST]

Blocked on spec change to add entropy calculation.