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Merge pull request #53 from ittiam-systems:rtp_opus
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PiperOrigin-RevId: 453490088
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marcbaechinger committed Jun 9, 2022
2 parents 62497f2 + 165e706 commit a2a4504
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2 changes: 2 additions & 0 deletions RELEASENOTES.md
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Expand Up @@ -127,6 +127,8 @@
([#10165](https://github.com/google/ExoPlayer/issues/10165)).
* Add RTP reader for VP9
([#47](https://github.com/androidx/media/pull/64)).
* Add RTP reader for OPUS
([#53](https://github.com/androidx/media/pull/53)).
* Session:
* Fix NPE in MediaControllerImplLegacy
([#59](https://github.com/androidx/media/pull/59)).
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Expand Up @@ -46,6 +46,7 @@ public final class RtpPayloadFormat {
private static final String RTP_MEDIA_MPEG4_VIDEO = "MP4V-ES";
private static final String RTP_MEDIA_H264 = "H264";
private static final String RTP_MEDIA_H265 = "H265";
private static final String RTP_MEDIA_OPUS = "OPUS";
private static final String RTP_MEDIA_PCM_L8 = "L8";
private static final String RTP_MEDIA_PCM_L16 = "L16";
private static final String RTP_MEDIA_PCMA = "PCMA";
Expand All @@ -63,6 +64,7 @@ public static boolean isFormatSupported(MediaDescription mediaDescription) {
case RTP_MEDIA_H265:
case RTP_MEDIA_MPEG4_VIDEO:
case RTP_MEDIA_MPEG4_GENERIC:
case RTP_MEDIA_OPUS:
case RTP_MEDIA_PCM_L8:
case RTP_MEDIA_PCM_L16:
case RTP_MEDIA_PCMA:
Expand Down Expand Up @@ -92,6 +94,8 @@ public static String getMimeTypeFromRtpMediaType(String mediaType) {
return MimeTypes.AUDIO_AMR_WB;
case RTP_MEDIA_MPEG4_GENERIC:
return MimeTypes.AUDIO_AAC;
case RTP_MEDIA_OPUS:
return MimeTypes.AUDIO_OPUS;
case RTP_MEDIA_PCM_L8:
case RTP_MEDIA_PCM_L16:
return MimeTypes.AUDIO_RAW;
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Expand Up @@ -101,6 +101,9 @@
*/
private static final int DEFAULT_VP8_HEIGHT = 240;

/** RFC7587 Section 6.1 Sampling rate for OPUS is fixed at 48KHz. */
private static final int OPUS_CLOCK_RATE = 48_000;

/**
* Default width for VP9.
*
Expand Down Expand Up @@ -201,6 +204,12 @@ public int hashCode() {
!fmtpParameters.containsKey(PARAMETER_AMR_INTERLEAVING),
"Interleaving mode is not currently supported.");
break;
case MimeTypes.AUDIO_OPUS:
checkArgument(channelCount != C.INDEX_UNSET);
// RFC7587 Section 6.1: the RTP timestamp is incremented with a 48000 Hz clock rate
// for all modes of Opus and all sampling rates.
checkArgument(clockRate == OPUS_CLOCK_RATE, "Invalid OPUS clock rate.");
break;
case MimeTypes.VIDEO_MP4V:
checkArgument(!fmtpParameters.isEmpty());
processMPEG4FmtpAttribute(formatBuilder, fmtpParameters);
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Expand Up @@ -39,6 +39,8 @@ public RtpPayloadReader createPayloadReader(RtpPayloadFormat payloadFormat) {
case MimeTypes.AUDIO_AMR_NB:
case MimeTypes.AUDIO_AMR_WB:
return new RtpAmrReader(payloadFormat);
case MimeTypes.AUDIO_OPUS:
return new RtpOpusReader(payloadFormat);
case MimeTypes.AUDIO_RAW:
case MimeTypes.AUDIO_ALAW:
case MimeTypes.AUDIO_MLAW:
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/*
* Copyright 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.media3.exoplayer.rtsp.reader;

import static androidx.media3.common.util.Assertions.checkArgument;
import static androidx.media3.common.util.Assertions.checkStateNotNull;

import androidx.media3.common.C;
import androidx.media3.common.Format;
import androidx.media3.common.util.Log;
import androidx.media3.common.util.ParsableByteArray;
import androidx.media3.common.util.Util;
import androidx.media3.exoplayer.rtsp.RtpPacket;
import androidx.media3.exoplayer.rtsp.RtpPayloadFormat;
import androidx.media3.extractor.ExtractorOutput;
import androidx.media3.extractor.OpusUtil;
import androidx.media3.extractor.TrackOutput;
import java.util.List;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;

/**
* Parses an OPUS byte stream carried on RTP packets and extracts individual samples. Refer to
* RFC7845 for more details.
*/
/* package */ final class RtpOpusReader implements RtpPayloadReader {
private static final String TAG = "RtpOpusReader";
/* Opus uses a fixed 48KHz media clock RFC7845 Section 4. */
private static final long MEDIA_CLOCK_FREQUENCY = 48_000;

private final RtpPayloadFormat payloadFormat;

private @MonotonicNonNull TrackOutput trackOutput;

/**
* First received RTP timestamp. All RTP timestamps are dimension-less, the time base is defined
* by {@link #MEDIA_CLOCK_FREQUENCY}.
*/
private long firstReceivedTimestamp;

private long startTimeOffsetUs;
private int previousSequenceNumber;
private boolean foundOpusIDHeader;
private boolean foundOpusCommentHeader;

/** Creates an instance. */
public RtpOpusReader(RtpPayloadFormat payloadFormat) {
this.payloadFormat = payloadFormat;
this.firstReceivedTimestamp = C.INDEX_UNSET;
this.previousSequenceNumber = C.INDEX_UNSET;
}

// RtpPayloadReader implementation.

@Override
public void createTracks(ExtractorOutput extractorOutput, int trackId) {
trackOutput = extractorOutput.track(trackId, C.TRACK_TYPE_AUDIO);
trackOutput.format(payloadFormat.format);
}

@Override
public void onReceivingFirstPacket(long timestamp, int sequenceNumber) {
this.firstReceivedTimestamp = timestamp;
}

@Override
public void consume(
ParsableByteArray data, long timestamp, int sequenceNumber, boolean rtpMarker) {
checkStateNotNull(trackOutput);

/* RFC7845 Section 3.
* +---------+ +----------------+ +--------------------+ +-----
* |ID Header| | Comment Header | |Audio Data Packet 1 | | ...
* +---------+ +----------------+ +--------------------+ +-----
*/
if (!foundOpusIDHeader) {
validateOpusIdHeader(data);
List<byte[]> initializationData = OpusUtil.buildInitializationData(data.getData());
Format.Builder formatBuilder = payloadFormat.format.buildUpon();
formatBuilder.setInitializationData(initializationData);
trackOutput.format(formatBuilder.build());
foundOpusIDHeader = true;
} else if (!foundOpusCommentHeader) {
// Comment Header RFC7845 Section 5.2.
int sampleSize = data.limit();
checkArgument(sampleSize >= 8, "Comment Header has insufficient data");
String header = data.readString(8);
checkArgument(header.equals("OpusTags"), "Comment Header should follow ID Header");
foundOpusCommentHeader = true;
} else {
// Check that this packet is in the sequence of the previous packet.
int expectedSequenceNumber = RtpPacket.getNextSequenceNumber(previousSequenceNumber);
if (sequenceNumber != expectedSequenceNumber) {
Log.w(
TAG,
Util.formatInvariant(
"Received RTP packet with unexpected sequence number. Expected: %d; received: %d.",
expectedSequenceNumber, sequenceNumber));
}

// sending opus data.
int size = data.bytesLeft();
trackOutput.sampleData(data, size);
long timeUs = toSampleTimeUs(startTimeOffsetUs, timestamp, firstReceivedTimestamp);
trackOutput.sampleMetadata(
timeUs, C.BUFFER_FLAG_KEY_FRAME, size, /* offset*/ 0, /* cryptoData*/ null);
}
previousSequenceNumber = sequenceNumber;
}

@Override
public void seek(long nextRtpTimestamp, long timeUs) {
firstReceivedTimestamp = nextRtpTimestamp;
startTimeOffsetUs = timeUs;
}

// Internal methods.

/**
* Validates the OPUS ID Header at {@code data}'s current position, throws {@link
* IllegalArgumentException} if the header is invalid.
*
* <p>{@code data}'s position does not change after returning.
*/
private static void validateOpusIdHeader(ParsableByteArray data) {
int currPosition = data.getPosition();
int sampleSize = data.limit();
checkArgument(sampleSize > 18, "ID Header has insufficient data");
String header = data.readString(8);
// Identification header RFC7845 Section 5.1.
checkArgument(header.equals("OpusHead"), "ID Header missing");
checkArgument(data.readUnsignedByte() == 1, "version number must always be 1");
data.setPosition(currPosition);
}

/** Returns the correct sample time from RTP timestamp, accounting for the OPUS sampling rate. */
private static long toSampleTimeUs(
long startTimeOffsetUs, long rtpTimestamp, long firstReceivedRtpTimestamp) {
return startTimeOffsetUs
+ Util.scaleLargeTimestamp(
rtpTimestamp - firstReceivedRtpTimestamp,
/* multiplier= */ C.MICROS_PER_SECOND,
/* divisor= */ MEDIA_CLOCK_FREQUENCY);
}
}
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