Hop mode doesn't work with an android screenlocked

[bricewge]

When listening on an android phone with the screen locked the hope modes (return or stay) doesn't work. Up until an add appear on the radio channel for the first time it works fine, but it fail to switch to the next channel when the add is detected or recover from it.

My guess is that the player stop outputting sound from the webpage when switching channel and that android don't allow a webpage to start playing a sound when the device's screen is off.
Keeping the player up in-between switching channels would probably solve the issue.

Thanks a lot for adblockradio, I had been waiting for something like it forever! I'm eager to see it in an dedicated device/radio.

[TeChn4K]

Thanks for your report!

We know that we have some issue with the player minimized or backgrounded... Mute mode works great because sound volume is simply reduced during ads/talks.
We can try some tricks like the one you proposed, but it will be hard to switch from one radio stream to another without stop playing...

@dest4 have you made some experiments previously about this subject?

[dest4]

Thanks for your report. I have received this feedback several times, it should be our priority now.
If I understood @bricewge correctly, the trick would be to have two media players. One would stop the first media player only when the second one has started playing audio. We need to test this though, I am not sure it would work.

[dest4]

By the way we have a similar issue in iOS.

[bricewge]

If I understood @bricewge correctly, the trick would be to have two media players. One would stop the first media player only when the second one has started playing audio.

Not really, let me try to explain it more clearly. The native player UI, that allow you to control the media on the notification screen of your OS, should never close. So when switching radio channels, the webapp need to stitch the 2 audio stream, without closing the notification player. To get something like channel1 audio -(close channel1)-> no sound (but player still open) -(open channel2)-> channel2 audio. I'm not sure if it's the way to go though.

I took a look at the code in src/components/MediaElement.js but got scared since I don't know any React.

[TeChn4K]

So I started the investigations, and it's not very conclusive yet...

I created a test page to reproduce this issue, with a similar context that the actual player. It includes MediaElement library and it switch between two radio streams every 5s.

That allows me to try different situations, like :

• React states to switch between streams by recreating audio tag
• React states to switch between streams by using MediaElement API
• vanilla JS and MediaElement API
• Use of a WebWorker (instead of the UI) to run all setInterval

Android 9, Firefox, screen off and locked.

About the last, you can read more here : https://stackoverflow.com/questions/5927284/how-can-i-make-setinterval-also-work-when-a-tab-is-inactive-in-chrome
And I tried with this library: https://github.com/turuslan/HackTimer

All these experiments have the same common issue: it start to fail after ~5min. Playback simply stops. It will behave perfectly fine again after a screen wake up.

[TeChn4K]

Now this is my current reading : https://www.html5rocks.com/en/tutorials/webaudio/intro/
Looks interesting! Mix two streams, crossfade, and never stop playing.
But it will resolves nothing if backgrounded browsers don't let us execute any code at all... I will give a try to be in the picture.

[TeChn4K]

Before all, Web Audio API doesn't support live stream for now. I read somewhere this is a work in progress. For now we have to rely on an HTMLAudioElement (audio tag) and connect it to our AudioContext via createMediaElementSource().

It looks a little bit wonky to me. But anyway, it works, and it allows us right now to use this powerful new Web Audio API.

I developed a small sandbox to experiment crossfading between two sources. You can try it here: https://testaudio.techn4k.now.sh/

Both streams will play across a common AudioContext, so playback never stops when you crossfade or stop one stream.

Click the "auto crossfade" button to alternate between each source every 10s.
Stream1 is playing -> Start stream2 -> Crossfade to stream2 -> Stop stream1. U-turn and start over.
Lock your phone and tell me what happen!

[TeChn4K]

40min without any playback issue, sounds promising!

[TeChn4K]

Before to dive into this deep sea, I would like to be sure this proposal resolves this issue or at least greatly improve it.
Please let me know how my sandbox works on your screen offed device. See my comment above.

In addition to the rewrite of the player, I would like to uncouple playback management (mute/switch on ads) from UI animations. This will allow to disable animations when the application is backgrounded.
I don't know exactly how browsers decide to limit tab running but I'm convinced it's not only because of playback stopping/starting. The lighter, the better!

[bricewge]

I didn't reported my feedback yesterday because it was quite inconclusive.

On Bromite (my Android browser) no sound was coming out from the speakers (even when using the play buttons) but the notification player was there. It is probably an issue from the browser.
Then I tried my native android browser (org.lineageos.jelly), where I got some sound but no notification player and it seems to keep playing for some time.

I'll try other devices with other browsers and report again. But it already seems a good start!

[bricewge]

I tried on two other devices with google chrome, no sound was playing but the player notification was visible.

[TeChn4K]

@bricewge you're right it's not working on Chrome Android... Firefox only. I'm on it.

[TeChn4K]

Playback is now working on Chrome and Firefox for Android.
Sorry for the inconvenience..
https://testaudio.techn4k.now.sh/