Notes:
- The way this works is that every time the player needs to
select some tracks it invokes the TrackSelector. When a
track selection is actually activated (i.e. "hits the
screen") it gets passed back to the TrackSelector, which
allows it to expose the current tracks through an API that
it may choose to define. Since playlist support doesn't exist
yet, it's currently the case that the pass-back always occurs
immediately.
- A TrackSelector can invalidate its previous selections if its
selection criteria changes. This will force the player to invoke
it again to make a new selection. If the new selection is the
same as the previous one for a renderer then the player handles
this efficiently (i.e. turns it into a no-op).
- DefaultTrackSelector supports disabling/enabling of renderers.
Separately, it supports overrides to select specific formats.
Since formats may change (playlists/periods), overrides are
specific to not only the renderer but also the set of formats
that are available to it. If the formats available to a renderer
change then the override will no longer apply. If the same set
of formats become available at some point later, it will apply
once more. This will nicely handle cases like ad-insertion where
the ads have different formats, but all segments of main content
use the same set of formats.
- In general, in multi-period or playlist cases, the preferred
way of selecting formats will be via constraints (e.g. "don't play
HD", "prefer higher quality audio") rather than explicit format
selections. The ability to set various constraints on
DefaultTrackSelector is future work.
Note about the demo app:
- I've removed the verbose log toggle. I doubt anyone has
ever used it! I've also removed the background audio option.
Without using a service it can't be considered a reference
implementation, so it's probably best to leave developers to
figure this one out. Finally, listening to AudioCapabilities
has also gone. This will be replaced by having the player
detect and handle the capabilities change internally in a
future CL. This will work by allowing a renderer to invalidate
the track selections when its capabilities change, much like
how a selector is able to invalidate the track selections in
this CL.
- It's now possible to enable ABR with an arbitrary subset of
tracks.
- Unsupported tracks are shown grayed out in the UI. I'm not
showing tracks that aren't associated to any renderer, but we
could optionally add that later.
- Every time the tracks change, there's logcat output showing
all of the tracks and which ones are enabled. Unassociated
tracks are displayed in this output.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=117122202
- I don't think the length is useful in hashCode; if the length
is different then Arrays.hashCode should account for that.
- "this." just for consistency across these classes.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=116641142
This change replaces TrackGroup[] with TrackGroupArray. This is
to allow equality based hashCode and equals implementations.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=115563146
