https://en.wikipedia.org/wiki/Dieter_Rams#/media/File:Dieter...
Although not standard, I'm thinking that a slider with a muted speaker icon to the left and a playing speaker icon to the right would be unambiguous.
I think these conventions are easily solved for video, anyway, because it's obvious when the video is muted or not (hopefully).
It isn’t always obvious to me. Sometimes I can’t tell if a video player is muted vs the system volume being low. There’s also the situation where a video is silent and I don’t know if I’m supposed to be hearing anything.
https://vintomatic.com/wp-content/uploads/2022/11/Vintomatic...
If the icon is a loudspeaker, then the LED should be on when the audio is on; but if the icon is a microphone with a bar across it, the LED should be on when the mic is off.
I have a button labelled "ASR OFF" in my car. Its LED is on when ASR is off and vice versa. I don't find it confusing.
Another example: my TV has a standby LED. It's off when the TV is on, and on when the TV is sleeping. Again, I find it correct.
Long ago, Apple's HI group had a saying: "a word is worth a thousand pictures".
In a conferencing app, for example, "mute" could mean switch audio off, or just the mic, or both.
And consider that a word, even "mute", might not have an equivalent in every languages.
Microphone Status:
( ) Muted
( ) Unmuted
Unambigious. Add icons if you like.If this was meant (semi)ironically and mainly as a reference to the OP link, then sorry for the earnest response!
Aside from that roughly 100% of applications I've been using use the "show current state" approach in this specific case. I don't think I've seen a media player which does it differently.
(speaker emitting sound / speaker crossed over). Ie the button has two icons with a slash between them.
One of the icons is in black outline and one is in grey outline. Pressing the button switches between what is black and what is gray.
If speaker emitting sound is black, then sound is on. If crossed speaker is black, then sound is muted.
We've got a video playing and an icon button which controls whether the video is muted. We've got a "playing speaker" and a "muted speaker" icon.
What's the correct pattern? Should the icon reflect the current state, or the expected state after pressing the button?