Media Element Playlist support

[ne0rrmatrix]

It would be nice to have support for playlists. ATM the players we use, AVPlayer, MediaPlayer.MediaElement and ExoPlayer all have buttons that do nothing. The next and previous track buttons do nothing. Well the previous button will reset the players position back to 0 and start playback again if you are playing content. But I am curious if there is any interest in adding the back end stuff for people to control this externally in their own implementation of multi-track audio/video?

My idea is to add support for the built in libraries that allow the players next/previous buttons to work. So adding the support for developers to add a playlist of files to the player and have the player handle the next previous buttons? All the players have built in libraries for doing this. I suggest we let the developer handle all logic for adding/removing and handling everything but the player buttons behavior. An example is the player would handle the process of actually going back and forth from one track to another but the developer would have to implement everything else.

How does having the player handle the playlist using existing libraries sound as an option? Adding methods that allow you to create a list of media items and add that to the player's que so that the next/previous button works?

We can use playlists as a way to handle this. An example in Android:

// Build the media items.
val firstItem = MediaItem.fromUri(firstVideoUri)
val secondItem = MediaItem.fromUri(secondVideoUri)
// Add the media items to be played.
player.addMediaItem(firstItem)
player.addMediaItem(secondItem)
// Prepare the player.
player.prepare()
// Start the playback.
player.play()

API

/// <summary>
/// Backing store for the <see cref="SourceList"/> property.
/// </summary>
public static readonly BindableProperty SourceListProperty =
	BindableProperty.Create(nameof(SourceList), typeof(List<MediaSource>), typeof(MediaElement), propertyChanging: OnSourceListPropertyChanging, propertyChanged: OnSourceListPropertyChanged);


public List<MediaSource> SourceList
{
	get => (List<MediaSource>)GetValue(SourceListProperty);
	set => SetValue(SourceListProperty, value);
}

We can wire up the player with support for adding/removing from the list. Oh and clear the list too. But this idea is simply to add support for the next/previous buttons and we can discuss any other further developments in the future? Does anyone have any suggestions are you all happy with this to start? Or is there no support for this and it is not needed?

Adding support for lists will allow us to add proper support for HLS and dash video which contain multiple tracks of audio/video/text. If the user just adds a single track it behaves like it always has. But when they add multiple tracks it just extends the behavior and does not change it. ATM we only have support for a single video added during initialization. We can choose source. But adding the ability to use a list will enable the two buttons. We can use the OnChanged event to handle logic of adding/removing items.

[ne0rrmatrix]

After playing around with this for a few hours I realized all we need to do is make sure media element supports adding lists of device specific types to fully support this. We don't need to do anything but add that. So no need to do anything but add conditionals to setting source!