"I do recall a Firefox discussion about how they can't 100% block videos because there will always be another way - eg do animated gifs count, or javascript that shows a rapid sequence of images [...]"
I also recall this being a justification given for auto-playing muted or audio-less video (i.e. because blocking "efficient" muted video playback will just lead to malicious actors using "less efficient" means of "image sequence" playback thus increasing the negative impact further).
On a related note, the other day I also discovered (while debugging why an audio demo didn't work the same way it did six years ago :D ) that there's now also a concept called "Sticky Activation" which can also impact "Autoplay of Media and Web Audio APIs (in particular for AudioContexts)"[1].
"I do recall a Firefox discussion about how they can't 100% block videos because there will always be another way - eg do animated gifs count, or javascript that shows a rapid sequence of images [...]"
I also recall this being a justification given for auto-playing muted or audio-less video (i.e. because blocking "efficient" muted video playback will just lead to malicious actors using "less efficient" means of "image sequence" playback thus increasing the negative impact further).
On a related note, the other day I also discovered (while debugging why an audio demo didn't work the same way it did six years ago :D ) that there's now also a concept called "Sticky Activation" which can also impact "Autoplay of Media and Web Audio APIs (in particular for AudioContexts)"[1].
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[0] https://news.ycombinator.com/item?id=43033814
[1] https://developer.mozilla.org/en-US/docs/Web/Security/User_a...