260468 2023-08-21 08:39:07 -0700 XSLT can take minutes to render with many <audio> elements 2023-09-29 02:11:39 -0700 1 1 1 Unclassified WebKit Media Safari 16 Mac (Apple Silicon) macOS 13 RESOLVED MOVED https://bugs.webkit.org/show_bug.cgi?id=262165 InRadar P2 Normal --- 1 jon webkit-unassigned ap eric.carlson jer.noble simon.fraser webkit-bug-importer zalan oldest_to_newest 1972380 0 jon 2023-08-21 08:39:07 -0700 I'd like to use XSLT to transform RSS feeds into user-viewable pages. When Safari renders lots of <audio> elements via XSLT, it behaves terribly - seemingly getting exponentially slower as the number of <audio> elements increases. On a sample feed with 515 episodes, Safari 16.5.2 appears to freeze while loading the page for around 52 seconds on my M1 Macbook Pro. Meanwhile a 2016 MBP takes 3 minutes 10 seconds… Firefox & Chrome both render the same page more-or-less instantly. Here’s the sample page with 515 episodes: https://d1k0jgp8xx8zuc.cloudfront.net/jds/xsl/fish.rss But for the sake of everyone’s sanity if you don’t want to sit there waiting for it to load, here’s a version with 100 episodes: https://d1k0jgp8xx8zuc.cloudfront.net/jds/xsl/fish-truncated.rss . It ‘only’ takes 5 seconds to render, but hopefully that’s enough to demonstrate the problem. (I've also filed this via Feedback Assistant, if that helps: FB12904190) 1972702 1 ap 2023-08-22 13:02:02 -0700 It is a known issue that rendering a page with many media elements is pathologically slow, but I cannot find the tracking bug now. Doing an outrageous amount of work under HTMLMediaElement::ensureMediaControls() -> HTMLMediaElement::setupAndCallJS() -> ... jsCSSStyleDeclaration_propertyValueForCamelCasedIDLAttribute() ... Document::updateStyleIfNeeded(). 1972703 2 webkit-bug-importer 2023-08-22 13:23:16 -0700 <rdar://problem/114278433> 1972752 3 ap 2023-08-22 15:16:03 -0700 rdar://113627244 1981093 4 simon.fraser 2023-09-28 14:34:43 -0700 This is covered by <rdar://77347577>. 1981227 5 jon 2023-09-29 02:11:39 -0700 Could you let us know the status of rdar://77347577 ?