[Galene] Re: Heads up: default video codec is now VP9

[Tim Panton <tim@pi.pe>]

> On 10 Jul 2023, at 10:04, Juliusz Chroboczek <jch@irif.fr> wrote:
> 
>> From our experience the deal with autoplay on safari is that you can
>> only successfully call play from a click.
> 
> Galene creates videos asynchronously, as people join and leave the group.
> We cannot require a click everytime somebody joins

You don’t need that - I think - if you have at least one <audio> or <video> tag playing already.
The problem crops up when that drops to zero.

> .
> 
> There's an (undocumented?) hack in Safari, which allows autoplay if a page
> holds a reference to a microphone or webcam stream.  So what we do is that
> we keep a reference to a microphone stream throughout a session.  That
> seems to work on iPad, so I'm surprised it doesn't work on desktop.

I’m not surprised - the iOS implementation is much closer to the hardware,  it allocates actual hardware resources on demand.
whereas the Mac one seems to have a multiplexing layer over the hardware which isolates things somewhat.

> 
> (Thankfully, we don't need to do that on other browsers, since users like
> the ability to follow a lecture on Galene without being required to grant
> microphone access.  Thanks to Safari's "security" features, videoconferencing
> software can spy on you.)

I think you can achieve the same thing by playing silent audio or ‘hold music' into a media tag. (Keeping the playing tags > zero) 
What you are seeing is that creating an echo cancelling mic session also allocates a playable output channel and so satisfies the criteria.

You still need a user click on chrome to activate play - but only for the first few sessions - which is a nightmare to test.

T.

> 
> -- Juliusz
>