Add bits per second for audio.

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/avi/AudioFormat.java

@@ -39,7 +39,9 @@ public class AudioFormat {
   public int getSamplesPerSecond() {
     return byteBuffer.getInt(4);
   }
-  // 8 - nAvgBytesPerSec(uint)
+  public int getAvgBytesPerSec() {
+    return byteBuffer.getInt(8);
+  }
   // 12 - nBlockAlign
 //  public int getBlockAlign() {
 //    return byteBuffer.getShort(12);

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/avi/AviExtractor.java

@@ -272,10 +272,13 @@ public class AviExtractor implements Extractor {
       final TrackOutput trackOutput = output.track(streamId, C.TRACK_TYPE_AUDIO);
       final String mimeType = audioFormat.getMimeType();
       builder.setSampleMimeType(mimeType);
-      //builder.setCodecs(audioFormat.getCodec());
       builder.setChannelCount(audioFormat.getChannels());
       builder.setSampleRate(audioFormat.getSamplesPerSecond());
-      if (audioFormat.getFormatTag() == AudioFormat.WAVE_FORMAT_PCM) {
+      final int bytesPerSecond = audioFormat.getAvgBytesPerSec();
+      if (bytesPerSecond != 0) {
+        builder.setAverageBitrate(bytesPerSecond * 8);
+      }
+      if (MimeTypes.AUDIO_RAW.equals(mimeType)) {
         final short bps = audioFormat.getBitsPerSample();
         if (bps == 8) {
           builder.setPcmEncoding(C.ENCODING_PCM_8BIT);

library/extractor/src/test/java/com/google/android/exoplayer2/extractor/avi/AudioFormatTest.java

@@ -22,5 +22,6 @@ public class AudioFormatTest {
     Assert.assertEquals(0, audioFormat.getBitsPerSample()); //Not meaningful for AAC
     Assert.assertArrayEquals(CODEC_PRIVATE, audioFormat.getCodecData());
     Assert.assertEquals(MimeTypes.AUDIO_AAC, audioFormat.getMimeType());
+    Assert.assertEquals(20034, audioFormat.getAvgBytesPerSec());
   }
 }