Exoplayer adaptive hls streaming

匿名 (未验证) 提交于 2019-12-03 02:18:01

问题:

I am looking for good and simple example/explanation how to implement ExoPlayer for HLS Adaptive streaming. I am a newbie and do not have experience and knowledge so I can figure how to do this from code example on git.

There are too many 'moving parts' so beginner can understand and reuse it in own projects.

Can somebody help me to learn and understand how to use/implement ExoPlayer in order to achieve this functionality?

Thanks!

回答1:

The easiest way to get started using ExoPlayer is to add it as a gradle dependency. You need to make sure you have the jcenter repository included in the build.gradle file in the root of your project:

repositories { jcenter() }

Next, include the following in your module's build.gradle file:

compile 'com.google.android.exoplayer:exoplayer:r2.2.0'

1. Your Layout File

    <?xml version="1.0" encoding="utf-8"?> <FrameLayout     android:id="@+id/activity_main"     xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:app="http://schemas.android.com/apk/res-auto"     android:layout_width="match_parent"     android:layout_height="match_parent">      <com.google.android.exoplayer2.ui.SimpleExoPlayerView         android:id="@+id/player_view"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:focusable="true"         app:resize_mode="fill"/>      <ProgressBar         android:id="@+id/progressBar"         style="?android:attr/progressBarStyle"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_gravity="center"         android:visibility="gone"/>  </FrameLayout> 

2. Your Class File(Activity)

    public class VideoPlayerActivity extends AppCompatActivity implements ExoPlayer.EventListener {      private SimpleExoPlayerView simpleExoPlayerView;     private String hlsVideoUri = "http://playertest.longtailvideo.com/adaptive/bbbfull/bbbfull.m3u8";     private SimpleExoPlayer player;     private ProgressBar progressBar;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_video_player);          // 1. Create a default TrackSelector         Handler mainHandler = new Handler();         BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();         TrackSelection.Factory videoTrackSelectionFactory = new AdaptiveVideoTrackSelection.Factory(bandwidthMeter);         TrackSelector trackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);          // 2. Create a default LoadControl         LoadControl loadControl = new DefaultLoadControl();           // 3. Create the player         player = ExoPlayerFactory.newSimpleInstance(this, trackSelector, loadControl);          simpleExoPlayerView = (SimpleExoPlayerView) findViewById(R.id.player_view);         simpleExoPlayerView.setPlayer(player);          // Measures bandwidth during playback. Can be null if not required.         DefaultBandwidthMeter defaultBandwidthMeter = new DefaultBandwidthMeter();         // Produces DataSource instances through which media data is loaded.         DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(this,                 Util.getUserAgent(this, "Exo2"), defaultBandwidthMeter);         // Produces Extractor instances for parsing the media data.         ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();         // This is the MediaSource representing the media to be played.         HlsMediaSource hlsMediaSource = new HlsMediaSource(Uri.parse(hlsVideoUri), dataSourceFactory, mainHandler, new AdaptiveMediaSourceEventListener() {             @Override             public void onLoadStarted(DataSpec dataSpec, int dataType, int trackType, Format trackFormat, int trackSelectionReason, Object trackSelectionData, long mediaStartTimeMs, long mediaEndTimeMs, long elapsedRealtimeMs) {              }              @Override             public void onLoadCompleted(DataSpec dataSpec, int dataType, int trackType, Format trackFormat, int trackSelectionReason, Object trackSelectionData, long mediaStartTimeMs, long mediaEndTimeMs, long elapsedRealtimeMs, long loadDurationMs, long bytesLoaded) {              }              @Override             public void onLoadCanceled(DataSpec dataSpec, int dataType, int trackType, Format trackFormat, int trackSelectionReason, Object trackSelectionData, long mediaStartTimeMs, long mediaEndTimeMs, long elapsedRealtimeMs, long loadDurationMs, long bytesLoaded) {              }              @Override             public void onLoadError(DataSpec dataSpec, int dataType, int trackType, Format trackFormat, int trackSelectionReason, Object trackSelectionData, long mediaStartTimeMs, long mediaEndTimeMs, long elapsedRealtimeMs, long loadDurationMs, long bytesLoaded, IOException error, boolean wasCanceled) {              }              @Override             public void onUpstreamDiscarded(int trackType, long mediaStartTimeMs, long mediaEndTimeMs) {              }              @Override             public void onDownstreamFormatChanged(int trackType, Format trackFormat, int trackSelectionReason, Object trackSelectionData, long mediaTimeMs) {              }         });          player.addListener(this);         player.prepare(hlsMediaSource);         simpleExoPlayerView.requestFocus();         player.setPlayWhenReady(true);          progressBar = (ProgressBar) findViewById(R.id.progressBar);     }      @Override     public void onTimelineChanged(Timeline timeline, Object manifest) {      }      @Override     public void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {      }      @Override     public void onLoadingChanged(boolean isLoading) {      }      @Override     public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {          switch (playbackState) {             case ExoPlayer.STATE_BUFFERING:                 //You can use progress dialog to show user that video is preparing or buffering so please wait                 progressBar.setVisibility(View.VISIBLE);                 break;             case ExoPlayer.STATE_IDLE:                 //idle state                 break;             case ExoPlayer.STATE_READY:                 // dismiss your dialog here because our video is ready to play now                 progressBar.setVisibility(View.GONE);                 break;             case ExoPlayer.STATE_ENDED:                 // do your processing after ending of video                 break;         }     }      @Override     public void onPlayerError(ExoPlaybackException error) {          AlertDialog.Builder adb = new AlertDialog.Builder(VideoPlayerActivity.this);         adb.setTitle("Could not able to stream video");         adb.setMessage("It seems that something is going wrong.\nPlease try again.");         adb.setPositiveButton("OK", new DialogInterface.OnClickListener() {             @Override             public void onClick(DialogInterface dialog, int which) {                 dialog.dismiss();                 finish(); // take out user from this activity. you can skip this             }         });         AlertDialog ad = adb.create();         ad.show();     }      @Override     public void onPositionDiscontinuity() {      }      @Override     protected void onPause() {         super.onPause();         if (player != null) {             player.setPlayWhenReady(false); //to pause a video because now our video player is not in focus         }     }      @Override     protected void onDestroy() {         super.onDestroy();         player.release();     } } 

I think this is enough for beginner. Also keep in mind that this library's standard audio and video components rely on Android’s MediaCodec API, which was released in Android 4.1 (API level 16). So it will not work on android 4.0 and below.

Don't forget to add this permission to the manifest file :

<uses-permission android:name="android.permission.INTERNET"/>



回答2:

The answer from @Vicky will work, but has one flaw.

The bandwidth meter that you pass to the track selector must be the same one that the datasource factory uses. The data source factory maintains the bandwidth estimate by calling the BW meter methods, and the adaptive track selection process gets the estimate to decide which track to adapt to.

If they are not the same instance, the adaptive selection always gets -1 as the BW, and picks some middle ground option.

The demo ExoPlayer apps also have this flaw. They pass false to the useBwMeter in buildDataSource(), which means no updating of the BW estimate



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