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Merge pull request #53 from ittiam-systems:rtp_opus
PiperOrigin-RevId: 453490088 (cherry picked from commit a2a4504)
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157
...ies/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpOpusReader.java
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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; | ||
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import static androidx.media3.common.util.Assertions.checkArgument; | ||
import static androidx.media3.common.util.Assertions.checkStateNotNull; | ||
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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; | ||
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/** | ||
* 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; | ||
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private final RtpPayloadFormat payloadFormat; | ||
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private @MonotonicNonNull TrackOutput trackOutput; | ||
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/** | ||
* First received RTP timestamp. All RTP timestamps are dimension-less, the time base is defined | ||
* by {@link #MEDIA_CLOCK_FREQUENCY}. | ||
*/ | ||
private long firstReceivedTimestamp; | ||
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private long startTimeOffsetUs; | ||
private int previousSequenceNumber; | ||
private boolean foundOpusIDHeader; | ||
private boolean foundOpusCommentHeader; | ||
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/** Creates an instance. */ | ||
public RtpOpusReader(RtpPayloadFormat payloadFormat) { | ||
this.payloadFormat = payloadFormat; | ||
this.firstReceivedTimestamp = C.INDEX_UNSET; | ||
this.previousSequenceNumber = C.INDEX_UNSET; | ||
} | ||
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// RtpPayloadReader implementation. | ||
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@Override | ||
public void createTracks(ExtractorOutput extractorOutput, int trackId) { | ||
trackOutput = extractorOutput.track(trackId, C.TRACK_TYPE_AUDIO); | ||
trackOutput.format(payloadFormat.format); | ||
} | ||
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@Override | ||
public void onReceivingFirstPacket(long timestamp, int sequenceNumber) { | ||
this.firstReceivedTimestamp = timestamp; | ||
} | ||
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@Override | ||
public void consume( | ||
ParsableByteArray data, long timestamp, int sequenceNumber, boolean rtpMarker) { | ||
checkStateNotNull(trackOutput); | ||
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/* 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)); | ||
} | ||
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// 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; | ||
} | ||
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@Override | ||
public void seek(long nextRtpTimestamp, long timeUs) { | ||
firstReceivedTimestamp = nextRtpTimestamp; | ||
startTimeOffsetUs = timeUs; | ||
} | ||
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// Internal methods. | ||
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/** | ||
* 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); | ||
} | ||
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/** 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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