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Merge pull request #46 from ittiam-systems:rtp_amr
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196
...ries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpAmrReader.java
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| Original file line number | Diff line number | Diff line change |
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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.checkNotNull; | ||
| import static androidx.media3.common.util.Assertions.checkStateNotNull; | ||
|
|
||
| import androidx.media3.common.C; | ||
| import androidx.media3.common.MimeTypes; | ||
| 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.TrackOutput; | ||
| import org.checkerframework.checker.nullness.qual.MonotonicNonNull; | ||
|
|
||
| /** | ||
| * Parses an AMR byte stream carried on RTP packets and extracts individual samples. Interleaving | ||
| * mode is not supported. Refer to RFC4867 for more details. | ||
| */ | ||
| /* package */ final class RtpAmrReader implements RtpPayloadReader { | ||
| private static final String TAG = "RtpAmrReader"; | ||
| /** | ||
| * The frame size in bytes, including header (1 byte), for each of the 16 frame types for AMR-NB | ||
| * (narrow band). AMR-NB supports eight narrow band speech encoding modes with bit rates between | ||
| * 4.75 and 12.2 kbps defined in RFC4867 Section 3.1. Refer to table 1a in 3GPP TS 26.101 for the | ||
| * mapping definition. | ||
| */ | ||
| private static final int[] AMR_NB_FRAME_TYPE_INDEX_TO_FRAME_SIZE = { | ||
| 13, // 4.75kbps | ||
| 14, // 5.15kbps | ||
| 16, // 5.90kbps | ||
| 18, // 6.70kbps PDC-EFR | ||
| 20, // 7.40kbps TDMA-EFR | ||
| 21, // 7.95kbps | ||
| 27, // 10.2kbps | ||
| 32, // 12.2kbps GSM-EFR | ||
| 6, // AMR SID | ||
| 7, // GSM-EFR SID | ||
| 6, // TDMA-EFR SID | ||
| 6, // PDC-EFR SID | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1 // No data | ||
| }; | ||
|
|
||
| /** | ||
| * The frame size in bytes, including header (1 byte), for each of the 16 frame types for AMR-WB | ||
| * (wide band). AMR-WB supports nine wide band speech encoding modes with bit rates between 6.6 to | ||
| * 23.85 kbps defined in RFC4867 Section 3.2. Refer to table 1a in 3GPP TS 26.201. for the mapping | ||
| * definition. | ||
| */ | ||
| private static final int[] AMR_WB_FRAME_TYPE_INDEX_TO_FRAME_SIZE = { | ||
| 18, // 6.60kbps | ||
| 24, // 8.85kbps | ||
| 33, // 12.65kbps | ||
| 37, // 14.25kbps | ||
| 41, // 15.85kbps | ||
| 47, // 18.25kbps | ||
| 51, // 19.85kbps | ||
| 59, // 23.05kbps | ||
| 61, // 23.85kbps | ||
| 6, // AMR-WB SID | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1, // speech lost | ||
| 1 // No data | ||
| }; | ||
|
|
||
| private final RtpPayloadFormat payloadFormat; | ||
| private final boolean isWideBand; | ||
| private final int sampleRate; | ||
|
|
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| private @MonotonicNonNull TrackOutput trackOutput; | ||
| private long firstReceivedTimestamp; | ||
| private long startTimeOffsetUs; | ||
| private int previousSequenceNumber; | ||
|
|
||
| public RtpAmrReader(RtpPayloadFormat payloadFormat) { | ||
| this.payloadFormat = payloadFormat; | ||
| this.isWideBand = | ||
| MimeTypes.AUDIO_AMR_WB.equals(checkNotNull(payloadFormat.format.sampleMimeType)); | ||
| this.sampleRate = payloadFormat.clockRate; | ||
| this.firstReceivedTimestamp = C.TIME_UNSET; | ||
| this.previousSequenceNumber = C.INDEX_UNSET; | ||
| // Start time offset must be 0 before the first seek. | ||
| this.startTimeOffsetUs = 0; | ||
| } | ||
|
|
||
| // 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); | ||
| // Check that this packet is in the sequence of the previous packet. | ||
| if (previousSequenceNumber != C.INDEX_UNSET) { | ||
| 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)); | ||
| } | ||
| } | ||
| // | ||
| // AMR as RTP payload (RFC4867 Section 4.2). | ||
| // | ||
| // +----------------+-------------------+---------------- | ||
| // | payload header | table of contents | speech data ... | ||
| // +----------------+-------------------+---------------- | ||
| // | ||
| // Payload header (RFC4867 Section 4.4.1). | ||
| // | ||
| // The header won't contain ILL and ILP, as interleaving is not currently supported. | ||
| // +-+-+-+-+-+-+-+- - - - - - - - | ||
| // | CMR |R|R|R|R| ILL | ILP | | ||
| // +-+-+-+-+-+-+-+- - - - - - - - | ||
| // | ||
| // Skip CMR and reserved bits. | ||
| data.skipBytes(1); | ||
| // Loop over sampleSize to send multiple frames along with appropriate timestamp when compound | ||
| // payload support is added. | ||
| int frameType = (data.peekUnsignedByte() >> 3) & 0x0f; | ||
| int frameSize = getFrameSize(frameType, isWideBand); | ||
| int sampleSize = data.bytesLeft(); | ||
| checkArgument(sampleSize == frameSize, "compound payload not supported currently"); | ||
| trackOutput.sampleData(data, sampleSize); | ||
| long sampleTimeUs = | ||
| toSampleTimeUs(startTimeOffsetUs, timestamp, firstReceivedTimestamp, sampleRate); | ||
| trackOutput.sampleMetadata( | ||
| sampleTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, /* offset= */ 0, /* cryptoData= */ null); | ||
|
|
||
| previousSequenceNumber = sequenceNumber; | ||
| } | ||
|
|
||
| @Override | ||
| public void seek(long nextRtpTimestamp, long timeUs) { | ||
| firstReceivedTimestamp = nextRtpTimestamp; | ||
| startTimeOffsetUs = timeUs; | ||
| } | ||
|
|
||
| // Internal methods. | ||
|
|
||
| public static int getFrameSize(int frameType, boolean isWideBand) { | ||
| checkArgument( | ||
| // Valid frame types are defined in RFC4867 Section 4.3.1. | ||
| (frameType >= 0 && frameType <= 8) || frameType == 15, | ||
| "Illegal AMR " + (isWideBand ? "WB" : "NB") + " frame type " + frameType); | ||
|
|
||
| return isWideBand | ||
| ? AMR_WB_FRAME_TYPE_INDEX_TO_FRAME_SIZE[frameType] | ||
| : AMR_NB_FRAME_TYPE_INDEX_TO_FRAME_SIZE[frameType]; | ||
| } | ||
|
|
||
| /** Returns the correct sample time from RTP timestamp, accounting for the AMR sampling rate. */ | ||
| private static long toSampleTimeUs( | ||
| long startTimeOffsetUs, long rtpTimestamp, long firstReceivedRtpTimestamp, int sampleRate) { | ||
| return startTimeOffsetUs | ||
| + Util.scaleLargeTimestamp( | ||
| rtpTimestamp - firstReceivedRtpTimestamp, | ||
| /* multiplier= */ C.MICROS_PER_SECOND, | ||
| /* divisor= */ sampleRate); | ||
| } | ||
| } |