Performance Tricks: Firefox Video, Twitter

I recently switched from Chromium to Firefox on MNT Reform and while I generally like the UI/UX a lot more, and the fact that it will run natively on wayland, I was unhappy with some performance details like video playback. It turns out that this is mostly related to GPU vs software scaling/compositing.

So, you can go to about:config and set layers.acceleration.force-enabled to true, but this will cause nasty GPU glitches. Trying to debug this today I recorded a Firefox session with apitrace. Strangely, the playback of the OpenGL capture was clean—no glitches to be seen. My unconfirmed intuition is that the glitches are some CPU/GPU buffer sharing problem. I discovered that setting dom.ipc.processCount to 1 instead of the default 8 greatly reduces the problem, so it appears to be inter-process/threading related. With this configuration, videos will be scaled to fullscreen smoothly: even software decoded 720p@60 FPS and 1080p@30 FPS works.

In a semi-related note, I was looking for an alternative to the Twitter website today, because it is unbearably slow. To my surprise, I found the previously unknown to me tweetdeck.twitter.com, which feels 10x faster than the regular Twitter web and also more customizable (you can remove “Trends”, for example).

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A different use-case to tweetdeck - but I use a self-hosted Nitter instance as a read-only front-end for twitter. It lacks an account system, so there’s no following or personalised timeline facilities yet (they’re planned). In the meanwhile it can generate an RSS feed for an account that you can use to replicate a timeline in an RSS reader.

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