Modify RtpPcmReader

Rename a few variable to be more relevant
Add detailed java docs

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtpPayloadFormat.java

@@ -93,22 +93,23 @@ public static String getMimeTypeFromRtpMediaType(String mediaType) {
   }
 
   /**
-   * Gets the PCM Encoding type for RAW track that is associated with the RTP media type.
+   * Gets the PCM Encoding type for audio encoding of track.
    *
-   * <p>For instance, RTP media type "L8" maps to {@link C.PcmEncoding#ENCODING_PCM_8BIT}.
+   * <p>For instance, Audio encoding "L8" has 8 bits/sample and thus maps to
+   * {@link C.PcmEncoding#ENCODING_PCM_8BIT}. Refer to RFC3551 Section 4.5 Table 1.
    *
-   * @throws IllegalArgumentException When the media type is not supported/recognized.
+   * @throws IllegalArgumentException When the audio encoding is not supported/recognized.
    */
-  public static int getPCMEncodingFromRtpMediaType(String mediaType) {
-    switch (mediaType) {
+  public static int getPcmEncodingFromAudioEncoding(String mediaEncoding) {
+    switch (mediaEncoding) {
       case RTP_MEDIA_PCM_L8:
-        // Refer to RFC3551#section-4.5.10
+        // Refer to RFC3551 Section 4.5.10
         return C.ENCODING_PCM_8BIT;
       case RTP_MEDIA_PCM_L16:
-        // Refer to RFC3551#section-4.5.11
+        // Refer to RFC3551 Section 4.5.11
         return C.ENCODING_PCM_16BIT_BIG_ENDIAN;
       default:
-        throw new IllegalArgumentException(mediaType);
+        throw new IllegalArgumentException("Unsupported RAW Audio Encoding " + mediaEncoding);
     }
   }
 

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtspMediaTrack.java

@@ -20,7 +20,7 @@
 import static androidx.media3.common.util.Util.castNonNull;
 import static androidx.media3.exoplayer.rtsp.MediaDescription.MEDIA_TYPE_AUDIO;
 import static androidx.media3.exoplayer.rtsp.RtpPayloadFormat.getMimeTypeFromRtpMediaType;
-import static androidx.media3.exoplayer.rtsp.RtpPayloadFormat.getPCMEncodingFromRtpMediaType;
+import static androidx.media3.exoplayer.rtsp.RtpPayloadFormat.getPcmEncodingFromAudioEncoding;
 import static androidx.media3.exoplayer.rtsp.SessionDescription.ATTR_CONTROL;
 import static androidx.media3.extractor.NalUnitUtil.NAL_START_CODE;
 
@@ -103,8 +103,9 @@ public int hashCode() {
     }
 
     int rtpPayloadType = mediaDescription.rtpMapAttribute.payloadType;
+    String mediaEncoding = mediaDescription.rtpMapAttribute.mediaEncoding;
 
-    String mimeType = getMimeTypeFromRtpMediaType(mediaDescription.rtpMapAttribute.mediaEncoding);
+    String mimeType = getMimeTypeFromRtpMediaType(mediaEncoding);
     formatBuilder.setSampleMimeType(mimeType);
 
     int clockRate = mediaDescription.rtpMapAttribute.clockRate;
@@ -131,8 +132,7 @@ public int hashCode() {
         processH265FmtpAttribute(formatBuilder, fmtpParameters);
         break;
       case MimeTypes.AUDIO_RAW:
-        int pcmEncoding =
-            getPCMEncodingFromRtpMediaType(mediaDescription.rtpMapAttribute.mediaEncoding);
+        int pcmEncoding = getPcmEncodingFromAudioEncoding(mediaEncoding);
         formatBuilder.setPcmEncoding(pcmEncoding);
         break;
       case MimeTypes.AUDIO_AC3:

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/DefaultRtpPayloadReaderFactory.java

@@ -43,7 +43,7 @@ public RtpPayloadReader createPayloadReader(RtpPayloadFormat payloadFormat) {
       case MimeTypes.AUDIO_RAW:
       case MimeTypes.AUDIO_ALAW:
       case MimeTypes.AUDIO_MLAW:
-        return new RtpPCMReader(payloadFormat);
+        return new RtpPcmReader(payloadFormat);
       default:
         // No supported reader, returning null.
     }

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpPCMReader.java → libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpPcmReader.java

@@ -29,16 +29,17 @@
  * Parses byte stream carried on RTP packets, and extracts PCM frames. Refer to RFC3551 for more
  * details.
  */
-/* package */ public final class RtpPCMReader implements RtpPayloadReader {
+/* package */ public final class RtpPcmReader implements RtpPayloadReader {
 
   private final RtpPayloadFormat payloadFormat;
   private @MonotonicNonNull TrackOutput trackOutput;
   private long firstReceivedTimestamp;
   private long startTimeOffsetUs;
 
-  public RtpPCMReader(RtpPayloadFormat payloadFormat) {
+  public RtpPcmReader(RtpPayloadFormat payloadFormat) {
     this.payloadFormat = payloadFormat;
     firstReceivedTimestamp = C.TIME_UNSET;
+    startTimeOffsetUs = 0;
   }
 
   @Override
@@ -62,9 +63,9 @@ public void consume(
     trackOutput.sampleData(data, size);
     trackOutput
         .sampleMetadata(
-            /* timeUs= */ sampleTimeUs,
-            /* flags= */ C.BUFFER_FLAG_KEY_FRAME,
-            /* size= */ size,
+            sampleTimeUs,
+            C.BUFFER_FLAG_KEY_FRAME,
+            size,
             /* offset= */ 0,
             /* cryptoData= */ null);
   }