In ExoPlayer every piece of media is represented by
MediaSource. The ExoPlayer
MediaSource implementations for several stream types:
ProgressiveMediaSourcefor regular media files.
Examples of instantiating all four can be found in
PlayerActivity in the main
In addition to the MediaSource implementations described above, the ExoPlayer
library also provides
implementations enable more complex playback functionality through composition.
Some of the common use cases are described below. Note that although some of the
following examples are described in the context of video playback, they apply
equally to audio only playback too, and indeed to the playback of any supported
Playing a playlist
Playlists are supported using
ConcatenatingMediaSource, which enables
sequential playback of multiple
MediaSources. It’s possible to dynamically
modify a playlist by adding, removing and moving
MediaSources within a
ConcatenatingMediaSource during playback. See the Playlists page for more
Clipping a video
ClippingMediaSource can be used to clip a
MediaSource so that only part of
it is played. The following example clips a video playback to start at 5 seconds
and end at 10 seconds.
MediaSource videoSource = new ProgressiveMediaSource.Factory(...).createMediaSource(videoUri); // Clip to start at 5 seconds and end at 10 seconds. ClippingMediaSource clippingSource = new ClippingMediaSource( videoSource, /* startPositionUs= */ 5_000_000, /* endPositionUs= */ 10_000_000);
To clip only the start of the source,
endPositionUs can be set to
C.TIME_END_OF_SOURCE. To clip only to a particular duration, there is a
constructor that takes a
When clipping the start of a video file, try to align the start position with a
keyframe if possible. If the start position is not aligned with a keyframe then
the player will need to decode and discard data from the previous keyframe up to
the start position before playback can begin. This will introduce a short delay
at the start of playback, including when the player transitions to playing the
ClippingMediaSource as part of a playlist or due to looping.
Looping a video
To loop indefinitely, it is better to use
A video can be seamlessly looped a fixed number of times using a
LoopingMediaSource. The following example plays a video twice.
MediaSource source = new ProgressiveMediaSource.Factory(...).createMediaSource(videoUri); // Plays the video twice. LoopingMediaSource loopingSource = new LoopingMediaSource(source, 2);
Side-loading a subtitle file
Given a video file and a separate subtitle file,
MergingMediaSource can be
used to merge them into a single source for playback.
// Build the video MediaSource. MediaSource videoSource = new ProgressiveMediaSource.Factory(...).createMediaSource(videoUri); // Build the subtitle MediaSource. Format subtitleFormat = Format.createTextSampleFormat( id, // An identifier for the track. May be null. MimeTypes.APPLICATION_SUBRIP, // The mime type. Must be set correctly. selectionFlags, // Selection flags for the track. language); // The subtitle language. May be null. MediaSource subtitleSource = new SingleSampleMediaSource.Factory(...) .createMediaSource(subtitleUri, subtitleFormat, C.TIME_UNSET); // Plays the video with the sideloaded subtitle. MergingMediaSource mergedSource = new MergingMediaSource(videoSource, subtitleSource);
It’s possible to further combine composite
MediaSources for more unusual use
cases. Given two videos A and B, the following example shows how
ConcatenatingMediaSource can be used together to play
the sequence (A,A,B).
MediaSource firstSource = new ProgressiveMediaSource.Factory(...).createMediaSource(firstVideoUri); MediaSource secondSource = new ProgressiveMediaSource.Factory(...).createMediaSource(secondVideoUri); // Plays the first video twice. LoopingMediaSource firstSourceTwice = new LoopingMediaSource(firstSource, 2); // Plays the first video twice, then the second video. ConcatenatingMediaSource concatenatedSource = new ConcatenatingMediaSource(firstSourceTwice, secondSource);
The following example is equivalent, demonstrating that there can be more than one way of achieving the same result.
MediaSource firstSource = new ProgressiveMediaSource.Factory(...).createMediaSource(firstVideoUri); MediaSource secondSource = new ProgressiveMediaSource.Factory(...).createMediaSource(secondVideoUri); // Plays the first video twice, then the second video. ConcatenatingMediaSource concatenatedSource = new ConcatenatingMediaSource(firstSource, firstSource, secondSource);