Merge pull request #320 from AgoraIO/fix-NMS-5469

[Android]optimize pushExternalAudioFrame timestamp.

Author: plutoless

Android/APIExample/app/src/main/java/io/agora/api/example/examples/advanced/customaudio/CustomAudioSource.java

@@ -54,6 +54,7 @@ public class CustomAudioSource extends BaseFragment implements View.OnClickListe
     public static RtcEngineEx engine;
     private Switch mic, pcm;
     private ChannelMediaOptions option = new ChannelMediaOptions();
+    private volatile int pushTimes = 0;
 
     private AudioSeatManager audioSeatManager;
     private AudioFileReader audioPushingHelper;
@@ -155,7 +156,8 @@ public void onActivityCreated(@Nullable Bundle savedInstanceState) {
 
             audioPushingHelper = new AudioFileReader(requireContext(), (buffer, timestamp) -> {
                 if(joined && engine != null){
-                    engine.pushExternalAudioFrame(buffer, timestamp);
+                    Log.i(TAG, "pushExternalAudioFrame times:" + pushTimes++);
+                    engine.pushExternalAudioFrame(buffer, 0);
                 }
             });
         } catch (Exception e) {
@@ -329,6 +331,7 @@ public void run() {
                     join.setEnabled(true);
                     join.setText(getString(R.string.leave));
                     if(audioPushingHelper != null){
+                        pushTimes = 0;
                         audioPushingHelper.start();
                     }
                     audioSeatManager.upLocalSeat(uid);

Android/APIExample/app/src/main/java/io/agora/api/example/utils/AudioFileReader.java

@@ -8,12 +8,17 @@
 
 public class AudioFileReader {
     private static final String AUDIO_FILE = "output.raw";
-    public static final Integer SAMPLE_RATE = 44100;
-    public static final Integer SAMPLE_NUM_OF_CHANNEL = 2;
-    public static final Integer BITS_PER_SAMPLE = 16;
-    private static final Integer SAMPLES = 441;
-    private static final Integer BUFFER_SIZE = SAMPLES * BITS_PER_SAMPLE / 8 * SAMPLE_NUM_OF_CHANNEL;
-    private static final Integer PUSH_INTERVAL = SAMPLES * 1000 / SAMPLE_RATE;
+    public static final int SAMPLE_RATE = 44100;
+    public static final int SAMPLE_NUM_OF_CHANNEL = 2;
+    public static final int BITS_PER_SAMPLE = 16;
+
+    public static final float BYTE_PER_SAMPLE = 1.0f * BITS_PER_SAMPLE / 8 * SAMPLE_NUM_OF_CHANNEL;
+    public static final float DURATION_PER_SAMPLE = 1000.0f / SAMPLE_RATE; // ms
+    public static final float SAMPLE_COUNT_PER_MS = SAMPLE_RATE * 1.0f / 1000; // ms
+
+    private static final int BUFFER_SAMPLE_COUNT = (int) (SAMPLE_COUNT_PER_MS * 10); // 10ms sample count
+    private static final int BUFFER_BYTE_SIZE = (int) (BUFFER_SAMPLE_COUNT * BYTE_PER_SAMPLE); // byte
+    private static final long BUFFER_DURATION = (long) (BUFFER_SAMPLE_COUNT * DURATION_PER_SAMPLE); // ms
 
     private final Context context;
     private final OnAudioReadListener audioReadListener;
@@ -62,16 +67,21 @@ public void run() {
             }
             Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_AUDIO);
             pushing = true;
+
+            long start_time = System.currentTimeMillis();;
+            int sent_audio_frames = 0;
             while (pushing) {
-                long before = System.currentTimeMillis();
                 if(audioReadListener != null){
                     audioReadListener.onAudioRead(readBuffer(), System.currentTimeMillis());
                 }
+                ++ sent_audio_frames;
+                long next_frame_start_time = sent_audio_frames * BUFFER_DURATION + start_time;
                 long now = System.currentTimeMillis();
-                long consuming = now - before;
-                if(consuming < PUSH_INTERVAL){
+
+                if(next_frame_start_time > now){
+                    long sleep_duration = next_frame_start_time - now;
                     try {
-                        Thread.sleep(PUSH_INTERVAL - consuming);
+                        Thread.sleep(sleep_duration);
                     } catch (InterruptedException e) {
                         e.printStackTrace();
                     }
@@ -90,7 +100,7 @@ public void run() {
         }
 
         private byte[] readBuffer() {
-            int byteSize = BUFFER_SIZE;
+            int byteSize = BUFFER_BYTE_SIZE;
             byte[] buffer = new byte[byteSize];
             try {
                 if (inputStream.read(buffer) < 0) {