There seem to be a bug with MP4 video processing it eats CPU and battery like cr...

rene_bg · on Nov 25, 2017

You can use [1] to force YouTube videos being streamed as H.264 instead of VP8/9. This helps with the battery issue (at least on YouTube).

[1]: https://addons.mozilla.org/en-US/firefox/addon/h264ify/

vim_wannabe · on Nov 25, 2017

I think browser makers (or whoever it needs to be) should offer an option to save battery over a little bit of extra bandwidth. Maybe even make it the default.

the8472 · on Nov 25, 2017

youtube's logic selects the codec, not the browser

pests · on Nov 26, 2017

Not if the browser only advertises support for the one it wants YouTube to pick.

ComputerGuru · on Nov 25, 2017

No, it’s a negotiation wherein the client submits its list of supported protocols and the server chooses between them.

icebraining · on Nov 25, 2017

And since FF supports both, it's YouTube which is choosing the codec, as the8472 wrote.

pests · on Nov 26, 2017

And what vim_coder and ConputerGuru meant was that Firefox would present a spoofed list of supported codecs to YouTube to force selection of the higher bandwidth, lower-powered codec.

Just because Firefox technically supports a format doesn't mean it has to disclose that format to external servers for selection.

icebraining · on Nov 26, 2017

Having custom behaviors for specific sites is a terrible practice. Browsers are complex enough as they are without an extra layer of hacks.

ComputerGuru · on Nov 26, 2017

Who said anything about custom behavior for custom sites? A simple “on battery? X264/265 only” is what’s being discussed here.

the8472 · on Nov 26, 2017

That does not work because the browser that does not know how much it can reduce the presented feature-set without actually breaking the site. Some content is vpx-only.

username223 · on Nov 26, 2017

It seems just about the same as having custom behaviors for specific user agents. Sadly, that's how things work these days.

frik · on Nov 25, 2017

Good to know, but at least for me actually occurs with MP4 files. I tried it on my own video MP4/H.264 files - loading the video with the video tag with plain HTML5. I am sure the FF devs know about the FF57 video bug and have fixed it already in nightly build or are working on it.