Integrate the ExoPlayer library

LICENSE

@@ -22,7 +22,7 @@ SOFTWARE.
 
 ==============================================================================
 
-This software includes the sonic library which is licensed under the Apache
+This software includes the ExoPlayer library which is licensed under the Apache
 License, Version 2.0.
 
 

README.md

@@ -17,9 +17,11 @@ This plugin has been tested on Android, and is being made available for testing
 final player = AudioPlayer();
 await player.setUrl('https://foo.com/bar.mp3');
 player.play();
-await player.pause();
+player.pause();
-await player.play(untilPosition: Duration(minutes: 1));
+player.play();
-await player.stop()
+await player.stop();
+await player.setClip(start: Duration(seconds: 10), end: Duration(seconds: 20));
+await player.play();
 await player.setUrl('https://foo.com/baz.mp3');
 await player.seek(Duration(minutes: 5));
 player.play();

android/build.gradle

@@ -38,3 +38,10 @@ android {
         targetCompatibility 1.8
     }
 }
+
+dependencies {
+    implementation 'com.google.android.exoplayer:exoplayer-core:2.11.1'
+    implementation 'com.google.android.exoplayer:exoplayer-dash:2.11.1'
+    implementation 'com.google.android.exoplayer:exoplayer-hls:2.11.1'
+    implementation 'com.google.android.exoplayer:exoplayer-smoothstreaming:2.11.1'
+}

android/src/main/java/com/ryanheise/just_audio/AudioPlayer.java

@@ -1,13 +1,16 @@
 package com.ryanheise.just_audio;
 
-import android.media.AudioFormat;
-import android.media.AudioManager;
-import android.media.AudioTrack;
-import android.media.MediaCodec;
-import android.media.MediaExtractor;
-import android.media.MediaFormat;
-import android.media.MediaTimestamp;
 import android.os.Handler;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.PlaybackParameters;
+import com.google.android.exoplayer2.SimpleExoPlayer;
+import com.google.android.exoplayer2.source.ClippingMediaSource;
+import com.google.android.exoplayer2.source.MediaSource;
+import com.google.android.exoplayer2.source.ProgressiveMediaSource;
+import com.google.android.exoplayer2.upstream.DataSource;
+import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;
+import com.google.android.exoplayer2.util.Util;
 import io.flutter.plugin.common.EventChannel;
 import io.flutter.plugin.common.EventChannel.EventSink;
 import io.flutter.plugin.common.MethodCall;
@@ -19,13 +22,14 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Deque;
 import java.util.LinkedList;
+import android.content.Context;
+import android.net.Uri;
 import java.util.List;
-import sonic.Sonic;
 
-public class AudioPlayer implements MethodCallHandler {
+public class AudioPlayer implements MethodCallHandler, Player.EventListener {
 	private final Registrar registrar;
+	private final Context context;
 	private final MethodChannel methodChannel;
 	private final EventChannel eventChannel;
 	private EventSink eventSink;
@@ -44,33 +48,26 @@ public class AudioPlayer implements MethodCallHandler {
 	};
 
 	private final String id;
-	private String url;
 	private volatile PlaybackState state;
 	private PlaybackState stateBeforeSeek;
 	private long updateTime;
-	private int updatePosition;
+	private long updatePosition;
-	private Deque<SeekRequest> seekRequests = new LinkedList<>();
 
-	private MediaExtractor extractor;
+	private long duration;
-	private MediaFormat format;
+	private Long start;
-	private Sonic sonic;
+	private Long end;
-	private int channelCount;
-	private int sampleRate;
-	private int duration;
-	private MediaCodec codec;
-	private AudioTrack audioTrack;
-	private PlayThread playThread;
-	private int start;
-	private Integer untilPosition;
-	private Object monitor = new Object();
 	private float volume = 1.0f;
 	private float speed = 1.0f;
-	private Thread mainThread;
+	private Long seekPos;
-	private byte[] chunk;
+	private Result prepareResult;
+	private Result seekResult;
+	private MediaSource mediaSource;
+
+	private SimpleExoPlayer player;
 
 	public AudioPlayer(final Registrar registrar, final String id) {
-		mainThread = Thread.currentThread();
 		this.registrar = registrar;
+		this.context = registrar.activeContext();
 		this.id = id;
 		methodChannel = new MethodChannel(registrar.messenger(), "com.ryanheise.just_audio.methods." + id);
 		methodChannel.setMethodCallHandler(this);
@@ -87,11 +84,47 @@ public class AudioPlayer implements MethodCallHandler {
 			}
 		});
 		state = PlaybackState.none;
+
+		player = new SimpleExoPlayer.Builder(context).build();
+		player.addListener(this);
+	}
+
+	@Override
+	public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
+		switch (playbackState) {
+		case Player.STATE_READY:
+			if (prepareResult != null) {
+				duration = player.getDuration();
+				prepareResult.success(duration);
+				prepareResult = null;
+				transition(PlaybackState.stopped);
+			}
+			break;
+		case Player.STATE_BUFFERING:
+			// TODO: use this instead of checkForDiscontinuity.
+			break;
+		case Player.STATE_ENDED:
+			if (state != PlaybackState.completed) {
+				transition(PlaybackState.completed);
+			}
+			break;
+		}
+	}
+
+	@Override
+	public void onSeekProcessed() {
+		if (seekResult != null) {
+			seekPos = null;
+			transition(stateBeforeSeek);
+			seekResult.success(null);
+			stateBeforeSeek = null;
+			seekResult = null;
+		}
 	}
 
 	private void checkForDiscontinuity() {
 		final long now = System.currentTimeMillis();
-		final int position = getCurrentPosition();
+		final long position = getCurrentPosition();
 		final long timeSinceLastUpdate = now - updateTime;
 		final long expectedPosition = updatePosition + (long)(timeSinceLastUpdate * speed);
 		final long drift = position - expectedPosition;
@@ -114,8 +147,19 @@ public class AudioPlayer implements MethodCallHandler {
 			case "setUrl":
 				setUrl((String)args.get(0), result);
 				break;
+			case "setClip":
+				Object start = args.get(0);
+				if (start != null && start instanceof Integer) {
+					start = new Long((Integer)start);
+				}
+				Object end = args.get(1);
+				if (end != null && end instanceof Integer) {
+					end = new Long((Integer)end);
+				}
+				setClip((Long)start, (Long)end, result);
+				break;
 			case "play":
-				play((Integer)args.get(0));
+				play();
 				result.success(null);
 				break;
 			case "pause":
@@ -134,7 +178,12 @@ public class AudioPlayer implements MethodCallHandler {
 				result.success(null);
 				break;
 			case "seek":
-				seek((Integer)args.get(0), result);
+				Object position = args.get(0);
+				if (position instanceof Integer) {
+					seek((Integer)position, result);
+				} else {
+					seek((Long)position, result);
+				}
 				break;
 			case "dispose":
 				dispose();
@@ -161,13 +210,13 @@ public class AudioPlayer implements MethodCallHandler {
 		eventSink.success(event);
 	}
 
-	private int getCurrentPosition() {
+	private long getCurrentPosition() {
 		if (state == PlaybackState.none || state == PlaybackState.connecting) {
 			return 0;
-		} else if (seekRequests.size() > 0) {
+		} else if (seekPos != null) {
-			return seekRequests.peekFirst().pos;
+			return seekPos;
 		} else {
-			return (int)(extractor.getSampleTime() / 1000);
+			return player.getCurrentPosition();
 		}
 	}
 
@@ -183,92 +232,47 @@ public class AudioPlayer implements MethodCallHandler {
 		broadcastPlaybackEvent();
 	}
 
-	private void bgTransition(final PlaybackState newState) {
-		bgTransition(state, newState);
-	}
-
-	private void bgTransition(final PlaybackState oldState, final PlaybackState newState) {
-		// Redundant assignment which ensures the state is set
-		// immediately in the background thread.
-		state = newState;
-		handler.post(new Runnable() {
-			@Override
-			public void run() {
-				transition(oldState, newState);
-			}
-		});
-	}
-
 	public void setUrl(final String url, final Result result) throws IOException {
-		if (state != PlaybackState.none && state != PlaybackState.stopped && state != PlaybackState.completed) {
+		prepareResult = result;
-			throw new IllegalStateException("Can call setUrl only from none/stopped/completed states (" + state + ")");
-		}
-		ensureStopped();
 		transition(PlaybackState.connecting);
-		this.url = url;
+		DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(context, Util.getUserAgent(context, "just_audio"));
-		if (extractor != null) {
+		mediaSource = new ProgressiveMediaSource.Factory(dataSourceFactory).createMediaSource(Uri.parse(url));
-			extractor.release();
+		player.prepare(mediaSource);
-		}
-		new Thread(() -> {
-			try {
-				blockingInitExtractorAndCodec();
-
-				sonic = new Sonic(sampleRate, channelCount);
-				sonic.setVolume(volume);
-				sonic.setSpeed(speed);
-
-				bgTransition(PlaybackState.stopped);
-				handler.post(() -> result.success(duration));
-			} catch (Exception e) {
-				e.printStackTrace();
-				handler.post(() -> result.error("Error: " + e, null, null));
-			}
-		}).start();
 	}
 
-	public void play(final Integer untilPosition) {
+	public void setClip(final Long start, final Long end, final Result result) {
-		if (untilPosition != null && untilPosition <= start) {
+		this.start = start;
-			throw new IllegalArgumentException("untilPosition must be >= 0");
+		this.end = end;
+		prepareResult = result;
+		if (start != null || end != null) {
+			player.prepare(new ClippingMediaSource(mediaSource,
+						(start != null ? start : 0) * 1000L,
+						(end != null ? end : C.TIME_END_OF_SOURCE) * 1000L));
+		} else {
+			player.prepare(mediaSource);
 		}
-		this.untilPosition = untilPosition;
+	}
+
+	public void play() {
 		switch (state) {
 		case stopped:
 		case completed:
-			ensureStopped();
+		case buffering:
-			transition(PlaybackState.playing);
-			playThread = new PlayThread();
-			playThread.start();
-			break;
 		case paused:
-			synchronized (monitor) {
+			player.setPlayWhenReady(true);
-				transition(PlaybackState.playing);
+			transition(PlaybackState.playing);
-				monitor.notifyAll();
-			}
 			break;
 		default:
 			throw new IllegalStateException("Can call play only from stopped, completed and paused states (" + state + ")");
 		}
 	}
 
-	private void ensureStopped() {
-		synchronized (monitor) {
-			try {
-				while (playThread != null) {
-					monitor.wait();
-				}
-			} catch (Exception e) {}
-		}
-	}
-
 	public void pause() {
 		switch (state) {
 		case playing:
 		case buffering:
-			synchronized (monitor) {
+			player.setPlayWhenReady(false);
-				transition(PlaybackState.paused);
+			transition(PlaybackState.paused);
-				audioTrack.pause();
-				monitor.notifyAll();
-			}
 			break;
 		default:
 			throw new IllegalStateException("Can call pause only from playing and buffering states (" + state + ")");
@@ -280,29 +284,14 @@ public class AudioPlayer implements MethodCallHandler {
 		case stopped:
 			result.success(null);
 			break;
-		case completed:
-			transition(PlaybackState.stopped);
-			result.success(null);
-			break;
 		// TODO: Allow stopping from buffered/connecting states.
+		case completed:
 		case playing:
 		case paused:
-			synchronized (monitor) {
+			player.setPlayWhenReady(false);
-				// It takes some time for the PlayThread to actually wind down
+			player.seekTo(0L);
-				// so other methods that transition from the stopped state should
+			transition(PlaybackState.stopped);
-				// wait for playThread == null with ensureStopped().
+			result.success(null);
-				PlaybackState oldState = state;
-				transition(PlaybackState.stopped);
-				if (oldState == PlaybackState.paused) {
-					monitor.notifyAll();
-				} else if (audioTrack != null) {
-					audioTrack.pause();
-				}
-				new Thread(() -> {
-					ensureStopped();
-					handler.post(() -> result.success(null));
-				}).start();
-			}
 			break;
 		default:
 			throw new IllegalStateException("Can call stop only from playing/paused/stopped/completed states (" + state + ")");
@@ -311,104 +300,32 @@ public class AudioPlayer implements MethodCallHandler {
 
 	public void setVolume(final float volume) {
 		this.volume = volume;
-		if (sonic != null) {
+		player.setVolume(volume);
-			sonic.setVolume(volume);
-		}
 	}
 
 	public void setSpeed(final float speed) {
-		// NOTE: existing audio data in the pipeline will continue
-		// to play out at the speed it was already processed at. So
-		// for a brief moment, checkForDiscontinuity() may erroneously
-		// detect some buffering.
-		// TODO: Sort this out. The cheap workaround would be to disable
-		// checks for discontinuity during this brief moment.
 		this.speed = speed;
-		if (sonic != null) {
+		player.setPlaybackParameters(new PlaybackParameters(speed));
-			sonic.setSpeed(speed);
-		}
 		broadcastPlaybackEvent();
 	}
 
-	// TODO: Test whether this times out the MediaCodec on Ogg files.
+	public void seek(final long position, final Result result) {
-	// See: https://stackoverflow.com/questions/22109050/mediacodec-dequeueoutputbuffer-times-out-when-seeking-with-ogg-audio-files
+		seekPos = position;
-	public void seek(final int position, final Result result) {
+		seekResult = result;
-		synchronized (monitor) {
+		if (stateBeforeSeek == null) {
-			if (state == PlaybackState.none || state == PlaybackState.connecting) {
+			stateBeforeSeek = state;
-				throw new IllegalStateException("Cannot call seek in none or connecting states (" + state + ")");
-			}
-			if (state == PlaybackState.stopped) {
-				ensureStopped();
-			}
-			start = position;
-			if (seekRequests.size() == 0) {
-				stateBeforeSeek = state;
-			}
-			seekRequests.addLast(new SeekRequest(position, result));
-			handler.removeCallbacks(positionObserver);
-			transition(PlaybackState.buffering);
-			if (stateBeforeSeek == PlaybackState.stopped) {
-				new Thread(() -> {
-					processSeekRequests();
-				}).start();
-			} else {
-				monitor.notifyAll();
-			}
 		}
+		handler.removeCallbacks(positionObserver);
+		transition(PlaybackState.buffering);
+		player.seekTo(position);
 	}
 
 	public void dispose() {
 		if (state != PlaybackState.stopped && state != PlaybackState.completed && state != PlaybackState.none) {
 			throw new IllegalStateException("Can call dispose only from stopped/completed/none states (" + state + ")");
 		}
-		if (extractor != null) {
+		player.release();
-			ensureStopped();
+		transition(PlaybackState.none);
-			transition(PlaybackState.none);
-			extractor.release();
-			extractor = null;
-			codec.stop();
-			codec.release();
-			codec = null;
-			chunk = null;
-		}
-	}
-
-	private void blockingInitExtractorAndCodec() throws IOException {
-		extractor = new MediaExtractor();
-		extractor.setDataSource(url);
-		format = selectAudioTrack(extractor);
-		channelCount = format.getInteger(MediaFormat.KEY_CHANNEL_COUNT);
-		sampleRate = format.getInteger(MediaFormat.KEY_SAMPLE_RATE);
-		long durationMs = format.getLong(MediaFormat.KEY_DURATION);
-		duration = (int)(durationMs / 1000);
-		start = 0;
-		codec = MediaCodec.createDecoderByType(format.getString(MediaFormat.KEY_MIME));
-		codec.configure(format, null, null, 0);
-		codec.start();
-	}
-
-	private MediaFormat selectAudioTrack(MediaExtractor extractor) throws IOException {
-		int trackCount = extractor.getTrackCount();
-		for (int i = 0; i < trackCount; i++) {
-			MediaFormat format = extractor.getTrackFormat(i);
-			if (format.getString(MediaFormat.KEY_MIME).startsWith("audio/")) {
-				extractor.selectTrack(i);
-				return format;
-			}
-		}
-		throw new RuntimeException("No audio track found");
-	}
-
-	private void processSeekRequests() {
-		while (seekRequests.size() > 0) {
-			SeekRequest seekRequest = seekRequests.removeFirst();
-			extractor.seekTo(seekRequest.pos*1000L, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
-			if (seekRequests.size() == 0) {
-				bgTransition(stateBeforeSeek);
-				stateBeforeSeek = null;
-			}
-			handler.post(() -> seekRequest.result.success(null));
-		}
 	}
 
 	private void startObservingPosition() {
@@ -416,208 +333,6 @@ public class AudioPlayer implements MethodCallHandler {
 		handler.post(positionObserver);
 	}
 
-	private class PlayThread extends Thread {
-		private static final int TIMEOUT = 1000;
-		private static final int FRAME_SIZE = 1024*2;
-		private static final int BEHIND_LIMIT = 500; // ms
-		private byte[] silence;
-		private boolean finishedDecoding = false;
-
-		@Override
-		public void run() {
-			boolean reachedEnd = false;
-			int encoding = AudioFormat.ENCODING_PCM_16BIT;
-			int channelFormat = channelCount==1?AudioFormat.CHANNEL_OUT_MONO:AudioFormat.CHANNEL_OUT_STEREO;
-			int minSize = AudioTrack.getMinBufferSize(sampleRate, channelFormat, encoding);
-			int audioTrackBufferSize = minSize * 4;
-			audioTrack = new AudioTrack(
-					AudioManager.STREAM_MUSIC,
-					sampleRate,
-					channelFormat,
-					encoding,
-					audioTrackBufferSize,
-					AudioTrack.MODE_STREAM);
-
-			silence = new byte[audioTrackBufferSize];
-
-			MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
-			boolean firstSample = true;
-			int decoderIdleCount = 0;
-			boolean finishedReading = false;
-			int progress = 0;
-			byte[] sonicOut = new byte[audioTrackBufferSize];
-			try {
-				audioTrack.play();
-				while (!finishedDecoding) {
-
-					if (checkForRequest()) continue;
-
-					// put data into input buffer
-
-					if (!finishedReading) {
-						int inputBufferIndex = codec.dequeueInputBuffer(TIMEOUT);
-						if (inputBufferIndex >= 0) {
-							ByteBuffer inputBuffer = codec.getInputBuffer(inputBufferIndex);
-							long presentationTime = extractor.getSampleTime();
-							int presentationTimeMs = (int)(presentationTime / 1000);
-							int sampleSize = extractor.readSampleData(inputBuffer, 0);
-							if (firstSample && sampleSize == 2 && format.getString(MediaFormat.KEY_MIME).equals("audio/mp4a-latm")) {
-								// Skip initial frames.
-								extractor.advance();
-							} else if (sampleSize >= 0) {
-								codec.queueInputBuffer(inputBufferIndex, 0, sampleSize, presentationTime, 0);
-								extractor.advance();
-							} else {
-								codec.queueInputBuffer(inputBufferIndex, 0, 0, -1, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
-								finishedReading = true;
-							}
-							firstSample = false;
-						}
-					}
-
-					if (checkForRequest()) continue;
-
-					// read data from output buffer
-
-					int outputBufferIndex = codec.dequeueOutputBuffer(info, TIMEOUT);
-					decoderIdleCount++;
-					if (outputBufferIndex >= 0) {
-						int currentPosition = (int)(info.presentationTimeUs/1000);
-						ByteBuffer buf = codec.getOutputBuffer(outputBufferIndex);
-						if (info.size > 0) {
-							decoderIdleCount = 0;
-
-							if (chunk == null || chunk.length < info.size) {
-								chunk = new byte[info.size];
-							}
-							buf.get(chunk, 0, info.size);
-							buf.clear();
-
-							// put decoded data into sonic
-
-							if (chunk.length > 0) {
-								sonic.writeBytesToStream(chunk, chunk.length);
-							} else {
-								sonic.flushStream();
-							}
-
-							// output sonic'd data to audioTrack
-
-							int numWritten;
-							do {
-								numWritten = sonic.readBytesFromStream(sonicOut, sonicOut.length);
-								if (numWritten > 0) {
-									audioTrack.write(sonicOut, 0, numWritten);
-								}
-							} while (numWritten > 0);
-						}
-
-						// Detect end of playback
-
-						codec.releaseOutputBuffer(outputBufferIndex, false);
-						if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
-							if (untilPosition != null) {
-								extractor.release();
-								codec.flush();
-								codec.stop();
-								codec.release();
-								blockingInitExtractorAndCodec();
-								finishedReading = false;
-								finishedDecoding = false;
-								decoderIdleCount = 0;
-								audioTrack.pause();
-								bgTransition(PlaybackState.paused);
-							} else {
-								audioTrack.pause();
-								finishedDecoding = true;
-								reachedEnd = true;
-							}
-						} else if (untilPosition != null && currentPosition >= untilPosition) {
-							// NOTE: When streaming audio over bluetooth, it clips off
-							// the last 200-300ms of the clip, even though it has been
-							// written to the AudioTrack. So, we need an option to pad the
-							// audio with an extra 200-300ms of silence.
-							// Could be a good idea to do the same at the start
-							// since some bluetooth headphones fade in and miss the
-							// first little bit.
-
-							Arrays.fill(sonicOut, (byte)0);
-							audioTrack.write(sonicOut, 0, sonicOut.length);
-							bgTransition(PlaybackState.paused);
-							audioTrack.pause();
-						}
-					} else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
-						// Don't expect this to happen in audio files, but could be wrong.
-						// TODO: Investigate.
-						//MediaFormat newFormat = codec.getOutputFormat();
-					}
-					if (decoderIdleCount >= 100) {
-						// Data has stopped coming through the pipeline despite not receiving a
-						// BUFFER_FLAG_END_OF_STREAM signal, so stop.
-						System.out.println("decoderIdleCount >= 100. finishedDecoding = true");
-						finishedDecoding = true;
-						audioTrack.pause();
-					}
-				}
-			} catch (IOException e) {
-				e.printStackTrace();
-			} finally {
-				codec.flush();
-				audioTrack.flush();
-				audioTrack.release();
-				audioTrack = null;
-				synchronized (monitor) {
-					start = 0;
-					untilPosition = null;
-					bgTransition(reachedEnd ? PlaybackState.completed : PlaybackState.stopped);
-					extractor.seekTo(0L, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
-					handler.post(() -> broadcastPlaybackEvent());
-					playThread = null;
-					monitor.notifyAll();
-				}
-			}
-		}
-
-		// Return true to "continue" to the audio loop
-		private boolean checkForRequest() {
-			try {
-				synchronized (monitor) {
-					if (state == PlaybackState.paused) {
-						while (state == PlaybackState.paused) {
-							monitor.wait();
-						}
-						// Unpaused
-						// Reset updateTime for higher accuracy.
-						bgTransition(state);
-						if (state == PlaybackState.playing) {
-							audioTrack.play();
-						} else if (state == PlaybackState.buffering) {
-							// TODO: What if we are in the second checkForRequest call and
-							// we ask to continue the loop, we may forget about dequeued
-							// input buffers. Need to handle this correctly.
-							return true;
-						}
-					} else if (state == PlaybackState.buffering && seekRequests.size() > 0) {
-						// Seek requested
-						codec.flush();
-						audioTrack.flush();
-						processSeekRequests();
-						if (state != PlaybackState.stopped) {
-							// The == stopped case is handled below.
-							return true;
-						}
-					}
-					if (state == PlaybackState.stopped) {
-						finishedDecoding = true;
-						return true;
-					}
-				}
-			}
-			catch (Exception e) {}
-			return false;
-		}
-	}
-
 	enum PlaybackState {
 		none,
 		stopped,
@@ -627,14 +342,4 @@ public class AudioPlayer implements MethodCallHandler {
 		connecting,
 		completed
 	}
-
-	class SeekRequest {
-		public final int pos;
-		public final Result result;
-
-		public SeekRequest(int pos, Result result) {
-			this.pos = pos;
-			this.result = result;
-		}
-	}
 }

ios/Classes/AudioPlayer.m

@@ -48,8 +48,11 @@
 	NSArray* args = (NSArray*)call.arguments;
 	if ([@"setUrl" isEqualToString:call.method]) {
 		[self setUrl:args[0] result:result];
+	} else if ([@"setClip" isEqualToString:call.method]) {
+		[self setClip:args[0] end:args[1]];
+		result(nil);
 	} else if ([@"play" isEqualToString:call.method]) {
-		[self play:args[0]];
+		[self play];
 		result(nil);
 	} else if ([@"pause" isEqualToString:call.method]) {
 		[self pause];
@@ -215,13 +218,14 @@
 	}
 }
 
-- (void)play:(NSNumber*)untilPosition {
+- (void)setClip:(NSNumber*)start end:(NSNumber*)end {
+	// TODO
+}
+
+- (void)play {
 	// TODO: dynamically adjust the lag.
 	//int lag = 6;
-	int start = [self getCurrentPosition];
+	//int start = [self getCurrentPosition];
-	if (untilPosition != [NSNull null] && [untilPosition intValue] <= start) {
-		return;
-	}
 	[_player play];
 	[self setPlaybackState:playing];
 	// TODO: convert this Android code to iOS

lib/just_audio.dart

@@ -13,9 +13,11 @@ import 'package:rxdart/rxdart.dart';
 /// final player = AudioPlayer();
 /// await player.setUrl('https://foo.com/bar.mp3');
 /// player.play();
-/// await player.pause();
+/// player.pause();
-/// await player.play(untilPosition: Duration(minutes: 1));
+/// player.play();
-/// await player.stop()
+/// await player.stop();
+/// await player.setClip(start: Duration(seconds: 10), end: Duration(seconds: 20));
+/// await player.play();
 /// await player.setUrl('https://foo.com/baz.mp3');
 /// await player.seek(Duration(minutes: 5));
 /// player.play();
@@ -171,27 +173,38 @@ class AudioPlayer {
   Future<File> get _cacheFile async => File(p.join(
       (await getTemporaryDirectory()).path, 'just_audio_asset_cache', '$_id'));
 
-  /// Plays the currently loaded media from the current position, until the
+  /// Clip the audio to the given [start] and [end] timestamps.
-  /// given position if specified. The [Future] returned by this method
+  Future<Duration> setClip({Duration start, Duration end}) async {
-  /// completes when playback completes or is paused or stopped. It is legal to
+    _durationFuture =
-  /// invoke this method only from one of the following states:
+        _invokeMethod('setClip', [start?.inMilliseconds, end?.inMilliseconds])
+            .then((ms) => Duration(milliseconds: ms));
+    final duration = await _durationFuture;
+    _durationSubject.add(duration);
+    return duration;
+  }
+
+  /// Plays the currently loaded media from the current position. The [Future]
+  /// returned by this method completes when playback completes or is paused or
+  /// stopped. It is legal to invoke this method only from one of the following
+  /// states:
   ///
   /// * [AudioPlaybackState.stopped]
   /// * [AudioPlaybackState.completed]
   /// * [AudioPlaybackState.paused]
-  Future<void> play({final Duration untilPosition}) async {
+  Future<void> play() async {
     StreamSubscription subscription;
     Completer completer = Completer();
     subscription = playbackStateStream
         .skip(1)
         .where((state) =>
             state == AudioPlaybackState.paused ||
-            state == AudioPlaybackState.stopped)
+            state == AudioPlaybackState.stopped ||
+            state == AudioPlaybackState.completed)
         .listen((state) {
       subscription.cancel();
       completer.complete();
     });
-    await _invokeMethod('play', [untilPosition?.inMilliseconds]);
+    await _invokeMethod('play');
     await completer.future;
   }