search

h5p / h5p-single-choice-set

MIT License
2 stars 63 forks source link

JI-3994 Remove usage of H5P.SoundJS #96

Closed fnoks closed 10 months ago

otacke commented 2 years ago

@fnoks Have you tested this on iOS in a real world setting over a cellular network? Playing audio can be delayed, because using the regular Audio iOS doesn't preload audio content in order to save bandwidth. At least that was a problem we faced around 1 year ago. WebAudio API was the way to go, and that's what SoundJS is using if I recall correctly.

fnoks commented 2 years ago

 @otacke : Thanks.

devland commented 10 months ago

@otacke The HTMLAudioElement has a preload property which defaults to auto. This means sounds are preloaded by default before they are played. You can test this by looking in your browser dev tools network tab. Sounds are loaded as soon as you set the src attribute on the audio object. You have to manually change preload to none for the sounds to be loaded when you play them. https://developer.mozilla.org/en-US/docs/Web/Media/Audio_and_video_delivery/Cross-browser_audio_basics

In some browsers preload defaults to metadata instead so I've updated the code to make sure preload is set to auto.

For our specific case, the 2 sounds that h5p-single-choice-set uses are below 45 kB in size each so preloading them, even on a mobile network, should not be a problem.

otacke commented 10 months ago

@devland Welcome to the world of Apple who often just "think differently". iOS ignores the 'preload' attribute as I tried to point out. See "Note: This value is often ignored on mobile platforms." in the document that you linked to and https://developer.apple.com/library/archive/documentation/AudioVideo/Conceptual/Using_HTML5_Audio_Video/AudioandVideoTagBasics/AudioandVideoTagBasics.html in particular. Cite: "Safari on iOS never preloads." That's why you will have a noticable delay on iOS (real devices, not neccessarily Browserstack). If that delay doesn't bother you, that's fine with me, but I wanted to point out that you will get one on iOS.

devland commented 10 months ago

@otacke I've updated the player.src so that it uses a dynamically generated binary url object via URL.createObjectURL based on a fetch response blob. This should bypass the need of relying on the preload attribute.

otacke commented 10 months ago

@devland As I said: I just wanted to point out that iOS needs some extra treatment and usually one uses the WebAudio API - I don't need to consent or be informed ;-) @fnoks Can't access JI-3994, so I cannot hint there that this should be tested on a real iOS phone (with a cellular network connection).