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Supports extracting from AMR container format.
Supports extracting data from AMR container format for both narrow and wide band formats. Also added AmrExtractor as one of the default extractor to be used in DefaultExtractorsFactory. GitHub: #2527. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=194407507
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library/core/src/main/java/com/google/android/exoplayer2/extractor/amr/AmrExtractor.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,299 @@ | ||
| /* | ||
| * Copyright (C) 2018 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 com.google.android.exoplayer2.extractor.amr; | ||
|
|
||
| import com.google.android.exoplayer2.C; | ||
| import com.google.android.exoplayer2.Format; | ||
| import com.google.android.exoplayer2.ParserException; | ||
| import com.google.android.exoplayer2.extractor.Extractor; | ||
| import com.google.android.exoplayer2.extractor.ExtractorInput; | ||
| import com.google.android.exoplayer2.extractor.ExtractorOutput; | ||
| import com.google.android.exoplayer2.extractor.ExtractorsFactory; | ||
| import com.google.android.exoplayer2.extractor.PositionHolder; | ||
| import com.google.android.exoplayer2.extractor.SeekMap; | ||
| import com.google.android.exoplayer2.extractor.TrackOutput; | ||
| import com.google.android.exoplayer2.util.MimeTypes; | ||
| import com.google.android.exoplayer2.util.Util; | ||
| import java.io.EOFException; | ||
| import java.io.IOException; | ||
| import java.util.Arrays; | ||
|
|
||
| /** | ||
| * Extracts data from the AMR containers format (either AMR or AMR-WB). This follows RFC-4867, | ||
| * section 5. | ||
| * | ||
| * <p>This extractor only supports single-channel AMR container formats. | ||
| */ | ||
| public final class AmrExtractor implements Extractor { | ||
|
|
||
| /** Factory for {@link AmrExtractor} instances. */ | ||
| public static final ExtractorsFactory FACTORY = | ||
| new ExtractorsFactory() { | ||
|
|
||
| @Override | ||
| public Extractor[] createExtractors() { | ||
| return new Extractor[] {new AmrExtractor()}; | ||
| } | ||
| }; | ||
|
|
||
| /** | ||
| * The frame size in bytes, including header (1 byte), for each of the 16 frame types for AMR | ||
| * narrow band. | ||
| */ | ||
| private static final int[] frameSizeBytesByTypeNb = { | ||
| 13, | ||
| 14, | ||
| 16, | ||
| 18, | ||
| 20, | ||
| 21, | ||
| 27, | ||
| 32, | ||
| 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 wide | ||
| * band. | ||
| */ | ||
| private static final int[] frameSizeBytesByTypeWb = { | ||
| 18, | ||
| 24, | ||
| 33, | ||
| 37, | ||
| 41, | ||
| 47, | ||
| 51, | ||
| 59, | ||
| 61, | ||
| 6, // AMR-WB SID | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1, // Future use | ||
| 1, // speech lost | ||
| 1 // No data | ||
| }; | ||
|
|
||
| private static final byte[] amrSignatureNb = Util.getUtf8Bytes("#!AMR\n"); | ||
| private static final byte[] amrSignatureWb = Util.getUtf8Bytes("#!AMR-WB\n"); | ||
|
|
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| /** Theoretical maximum frame size for a AMR frame. */ | ||
| private static final int MAX_FRAME_SIZE_BYTES = frameSizeBytesByTypeWb[8]; | ||
|
|
||
| private static final int SAMPLE_RATE_WB = 16_000; | ||
| private static final int SAMPLE_RATE_NB = 8_000; | ||
| private static final int SAMPLE_TIME_PER_FRAME_US = 20_000; | ||
|
|
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| private final byte[] scratch; | ||
|
|
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| private boolean isWideBand; | ||
| private long currentSampleTimeUs; | ||
| private int currentSampleTotalBytes; | ||
| private int currentSampleBytesRemaining; | ||
|
|
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| private TrackOutput trackOutput; | ||
| private boolean hasOutputFormat; | ||
|
|
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| public AmrExtractor() { | ||
| scratch = new byte[1]; | ||
| } | ||
|
|
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| // Extractor implementation. | ||
|
|
||
| @Override | ||
| public boolean sniff(ExtractorInput input) throws IOException, InterruptedException { | ||
| return readAmrHeader(input); | ||
| } | ||
|
|
||
| @Override | ||
| public void init(ExtractorOutput output) { | ||
| output.seekMap(new SeekMap.Unseekable(C.TIME_UNSET)); | ||
| trackOutput = output.track(/* id= */ 0, C.TRACK_TYPE_AUDIO); | ||
| output.endTracks(); | ||
| } | ||
|
|
||
| @Override | ||
| public int read(ExtractorInput input, PositionHolder seekPosition) | ||
| throws IOException, InterruptedException { | ||
| if (input.getPosition() == 0) { | ||
| if (!readAmrHeader(input)) { | ||
| throw new ParserException("Could not find AMR header."); | ||
| } | ||
| } | ||
| maybeOutputFormat(); | ||
| return readSample(input); | ||
| } | ||
|
|
||
| @Override | ||
| public void seek(long position, long timeUs) { | ||
| currentSampleTimeUs = 0; | ||
| currentSampleTotalBytes = 0; | ||
| currentSampleBytesRemaining = 0; | ||
| } | ||
|
|
||
| @Override | ||
| public void release() { | ||
| // Do nothing | ||
| } | ||
|
|
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| /* package */ static int frameSizeBytesByTypeNb(int frameType) { | ||
| return frameSizeBytesByTypeNb[frameType]; | ||
| } | ||
|
|
||
| /* package */ static int frameSizeBytesByTypeWb(int frameType) { | ||
| return frameSizeBytesByTypeWb[frameType]; | ||
| } | ||
|
|
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| /* package */ static byte[] amrSignatureNb() { | ||
| return Arrays.copyOf(amrSignatureNb, amrSignatureNb.length); | ||
| } | ||
|
|
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| /* package */ static byte[] amrSignatureWb() { | ||
| return Arrays.copyOf(amrSignatureWb, amrSignatureWb.length); | ||
| } | ||
|
|
||
| // Internal methods. | ||
|
|
||
| /** | ||
| * Peeks the AMR header from the beginning of the input, and consumes it if it exists. | ||
| * | ||
| * @param input The {@link ExtractorInput} from which data should be peeked/read. | ||
| * @return Whether the AMR header has been read. | ||
| */ | ||
| private boolean readAmrHeader(ExtractorInput input) throws IOException, InterruptedException { | ||
| if (peekAmrSignature(input, amrSignatureNb)) { | ||
| isWideBand = false; | ||
| input.skipFully(amrSignatureNb.length); | ||
| return true; | ||
| } else if (peekAmrSignature(input, amrSignatureWb)) { | ||
| isWideBand = true; | ||
| input.skipFully(amrSignatureWb.length); | ||
| return true; | ||
| } | ||
| return false; | ||
| } | ||
|
|
||
| /** Peeks from the beginning of the input to see if the given AMR signature exists. */ | ||
| private boolean peekAmrSignature(ExtractorInput input, byte[] amrSignature) | ||
| throws IOException, InterruptedException { | ||
| input.resetPeekPosition(); | ||
| byte[] header = new byte[amrSignature.length]; | ||
| input.peekFully(header, 0, amrSignature.length); | ||
| return Arrays.equals(header, amrSignature); | ||
| } | ||
|
|
||
| private void maybeOutputFormat() { | ||
| if (!hasOutputFormat) { | ||
| hasOutputFormat = true; | ||
| String mimeType = isWideBand ? MimeTypes.AUDIO_AMR_WB : MimeTypes.AUDIO_AMR_NB; | ||
| int sampleRate = isWideBand ? SAMPLE_RATE_WB : SAMPLE_RATE_NB; | ||
| trackOutput.format( | ||
| Format.createAudioSampleFormat( | ||
| /* id= */ null, | ||
| mimeType, | ||
| /* codecs= */ null, | ||
| /* bitrate= */ Format.NO_VALUE, | ||
| MAX_FRAME_SIZE_BYTES, | ||
| /* channelCount= */ 1, | ||
| sampleRate, | ||
| /* pcmEncoding= */ Format.NO_VALUE, | ||
| /* initializationData= */ null, | ||
| /* drmInitData= */ null, | ||
| /* selectionFlags= */ 0, | ||
| /* language= */ null)); | ||
| } | ||
| } | ||
|
|
||
| private int readSample(ExtractorInput extractorInput) throws IOException, InterruptedException { | ||
| if (currentSampleBytesRemaining == 0) { | ||
| try { | ||
| currentSampleTotalBytes = readNextSampleSize(extractorInput); | ||
| } catch (EOFException e) { | ||
| return RESULT_END_OF_INPUT; | ||
| } | ||
| currentSampleBytesRemaining = currentSampleTotalBytes; | ||
| } | ||
|
|
||
| int bytesAppended = | ||
| trackOutput.sampleData( | ||
| extractorInput, currentSampleBytesRemaining, /* allowEndOfInput= */ true); | ||
| if (bytesAppended == C.RESULT_END_OF_INPUT) { | ||
| return RESULT_END_OF_INPUT; | ||
| } | ||
| currentSampleBytesRemaining -= bytesAppended; | ||
| if (currentSampleBytesRemaining > 0) { | ||
| return RESULT_CONTINUE; | ||
| } | ||
|
|
||
| trackOutput.sampleMetadata( | ||
| currentSampleTimeUs, | ||
| C.BUFFER_FLAG_KEY_FRAME, | ||
| currentSampleTotalBytes, | ||
| /* offset= */ 0, | ||
| /* encryptionData= */ null); | ||
| currentSampleTimeUs += SAMPLE_TIME_PER_FRAME_US; | ||
| return RESULT_CONTINUE; | ||
| } | ||
|
|
||
| private int readNextSampleSize(ExtractorInput extractorInput) | ||
| throws IOException, InterruptedException { | ||
| extractorInput.resetPeekPosition(); | ||
| extractorInput.peekFully(scratch, /* offset= */ 0, /* length= */ 1); | ||
|
|
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| byte frameHeader = scratch[0]; | ||
| if ((frameHeader & 0x83) > 0) { | ||
| // The padding bits are at bit-1 positions in the following pattern: 1000 0011 | ||
| // Padding bits must be 0. | ||
| throw new ParserException("Invalid padding bits for frame header " + frameHeader); | ||
| } | ||
|
|
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| int frameType = (frameHeader >> 3) & 0x0f; | ||
| return getFrameSizeInBytes(frameType); | ||
| } | ||
|
|
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| private int getFrameSizeInBytes(int frameType) throws ParserException { | ||
| if (!isValidFrameType(frameType)) { | ||
| throw new ParserException( | ||
| "Illegal AMR " + (isWideBand ? "WB" : "NB") + " frame type " + frameType); | ||
| } | ||
|
|
||
| return isWideBand ? frameSizeBytesByTypeWb[frameType] : frameSizeBytesByTypeNb[frameType]; | ||
| } | ||
|
|
||
| private boolean isValidFrameType(int frameType) { | ||
| return frameType >= 0 | ||
| && frameType <= 15 | ||
| && (isWideBandValidFrameType(frameType) || isNarrowBandValidFrameType(frameType)); | ||
| } | ||
|
|
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| private boolean isWideBandValidFrameType(int frameType) { | ||
| // For wide band, type 10-13 are for future use. | ||
| return isWideBand && (frameType < 10 || frameType > 13); | ||
| } | ||
|
|
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| private boolean isNarrowBandValidFrameType(int frameType) { | ||
| // For narrow band, type 12-14 are for future use. | ||
| return !isWideBand && (frameType < 12 || frameType > 14); | ||
| } | ||
| } |
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