palefill VS HTML5test

It cannot render modern sites without a polyfill addon to improve compatibility because they are worried more about legacy extensions and an old UI than providing a usable browser https://martok.github.io/palefill/

https://martok.github.io/palefill/ or the direct link https://github.com/martok/palefill/releases/download/v1.26/palefill-1.26.xpi

Until the soon-to-be V32, you need https://martok.github.io/palefill/ to use github sites. Since they switched to only work on google chromium standards.

Almost-must-have addons I'd recommend out of the gate is https://martok.github.io/palefill/, for chromium polymer sites, like GitHub. https://github.com/gorhill/uBlock-for-firefox-legacy/releases, which is self-explanatory, and https://addons.palemoon.org/addon/ematrix/, which works well together with uBO and shows what's what re third party injections and can block them.

PaleFill for GitHub's chromium-only site: https://martok.github.io/palefill/

You'll need PaleFill (https://martok.github.io/palefill/) before you can install uBlock Origin though.

If you use Pale Moon and struggle with some modern websites, you can enable more HTML5 features by installing the Palefill add-on as well as setting these properties to true in about:config: dom.animations-api.compositing.enabled dom.animations-api.getAnimations.enabled dom.animations-api.implicit-keyframes.enabled dom.animations-api.timelines.enabled dom.dialog_element.enabled dom.getRootNode.enabled dom.imagecapture.enabled dom.push.enabled dom.serviceWorkers.enabled dom.storageManager.enabled dom.webcomponents.enabled media.av1.enabled media.getusermedia.audiocapture.enabled media.mediasource.webm.enabled media.track.enabled media.webspeech.synth.enabled media.webvtt.regions.enabled Keep in mind that some of them are experimental (like ImageCapture) and may be unstable.

Do you know that you can improve HTML5 support in Pale Moon by setting these properties to true in about:config? dom.animations-api.compositing.enabled dom.animations-api.getAnimations.enabled dom.animations-api.implicit-keyframes.enabled dom.animations-api.timelines.enabled dom.dialog_element.enabled dom.getRootNode.enabled dom.imagecapture.enabled dom.push.enabled dom.serviceWorkers.enabled dom.storageManager.enabled dom.webcomponents.enabled media.av1.enabled media.getusermedia.audiocapture.enabled media.mediasource.webm.enabled media.track.enabled media.webspeech.synth.enabled media.webvtt.regions.enabled Check the HTML5 Test before and after. Also install Palefill.

I just don't know what else I can do. I compared Chromium and Firefox in html5test.com, got same result. All browsers says they doesn't support H.265. I turned off HW acceleration, nothing changes. I installed ffmpeg-libs and other codecs from Fedora wiki. Nothing changes. Videos are same vp9 in browsers. I spent all day googling but nothing helpful.

What does https://html5test.com/ say for h.264, VP8, VP9 and Theora support? What does it say for aac, Opus, Vorbis and mp3 support?

You can use this website also https://html5test.com is really helpful with more datails

If I go on html5test.com, no matter which browser I use, H265 support is not enabled and I couldn't find any article online that explains why -- what am I missing here?

When I install Opera via flatpak and do html 5 test it says h264 is not supported, what can I do?

What does https://html5test.com/ say for h.264 and aac support?

The h264 test page shows the same output in both chromium and chrome, and i can play the same formats from this page