diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/wav/WavExtractor.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/wav/WavExtractor.java | 562 |
1 files changed, 562 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/wav/WavExtractor.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/wav/WavExtractor.java new file mode 100644 index 0000000000..d4ac3ef8e1 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/wav/WavExtractor.java @@ -0,0 +1,562 @@ +/* + * Copyright (C) 2016 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 org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.wav; + +import android.util.Pair; +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +import org.mozilla.thirdparty.com.google.android.exoplayer2.Format; +import org.mozilla.thirdparty.com.google.android.exoplayer2.ParserException; +import org.mozilla.thirdparty.com.google.android.exoplayer2.audio.WavUtil; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.Extractor; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorInput; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorOutput; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorsFactory; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.PositionHolder; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.TrackOutput; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.MimeTypes; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util; +import java.io.IOException; +import org.checkerframework.checker.nullness.qual.EnsuresNonNull; +import org.checkerframework.checker.nullness.qual.MonotonicNonNull; + +/** + * Extracts data from WAV byte streams. + */ +public final class WavExtractor implements Extractor { + + /** + * When outputting PCM data to a {@link TrackOutput}, we can choose how many frames are grouped + * into each sample, and hence each sample's duration. This is the target number of samples to + * output for each second of media, meaning that each sample will have a duration of ~100ms. + */ + private static final int TARGET_SAMPLES_PER_SECOND = 10; + + /** Factory for {@link WavExtractor} instances. */ + public static final ExtractorsFactory FACTORY = () -> new Extractor[] {new WavExtractor()}; + + @MonotonicNonNull private ExtractorOutput extractorOutput; + @MonotonicNonNull private TrackOutput trackOutput; + @MonotonicNonNull private OutputWriter outputWriter; + private int dataStartPosition; + private long dataEndPosition; + + public WavExtractor() { + dataStartPosition = C.POSITION_UNSET; + dataEndPosition = C.POSITION_UNSET; + } + + @Override + public boolean sniff(ExtractorInput input) throws IOException, InterruptedException { + return WavHeaderReader.peek(input) != null; + } + + @Override + public void init(ExtractorOutput output) { + extractorOutput = output; + trackOutput = output.track(0, C.TRACK_TYPE_AUDIO); + output.endTracks(); + } + + @Override + public void seek(long position, long timeUs) { + if (outputWriter != null) { + outputWriter.reset(timeUs); + } + } + + @Override + public void release() { + // Do nothing + } + + @Override + public int read(ExtractorInput input, PositionHolder seekPosition) + throws IOException, InterruptedException { + assertInitialized(); + if (outputWriter == null) { + WavHeader header = WavHeaderReader.peek(input); + if (header == null) { + // Should only happen if the media wasn't sniffed. + throw new ParserException("Unsupported or unrecognized wav header."); + } + + if (header.formatType == WavUtil.TYPE_IMA_ADPCM) { + outputWriter = new ImaAdPcmOutputWriter(extractorOutput, trackOutput, header); + } else if (header.formatType == WavUtil.TYPE_ALAW) { + outputWriter = + new PassthroughOutputWriter( + extractorOutput, + trackOutput, + header, + MimeTypes.AUDIO_ALAW, + /* pcmEncoding= */ Format.NO_VALUE); + } else if (header.formatType == WavUtil.TYPE_MLAW) { + outputWriter = + new PassthroughOutputWriter( + extractorOutput, + trackOutput, + header, + MimeTypes.AUDIO_MLAW, + /* pcmEncoding= */ Format.NO_VALUE); + } else { + @C.PcmEncoding + int pcmEncoding = WavUtil.getPcmEncodingForType(header.formatType, header.bitsPerSample); + if (pcmEncoding == C.ENCODING_INVALID) { + throw new ParserException("Unsupported WAV format type: " + header.formatType); + } + outputWriter = + new PassthroughOutputWriter( + extractorOutput, trackOutput, header, MimeTypes.AUDIO_RAW, pcmEncoding); + } + } + + if (dataStartPosition == C.POSITION_UNSET) { + Pair<Long, Long> dataBounds = WavHeaderReader.skipToData(input); + dataStartPosition = dataBounds.first.intValue(); + dataEndPosition = dataBounds.second; + outputWriter.init(dataStartPosition, dataEndPosition); + } else if (input.getPosition() == 0) { + input.skipFully(dataStartPosition); + } + + Assertions.checkState(dataEndPosition != C.POSITION_UNSET); + long bytesLeft = dataEndPosition - input.getPosition(); + return outputWriter.sampleData(input, bytesLeft) ? RESULT_END_OF_INPUT : RESULT_CONTINUE; + } + + @EnsuresNonNull({"extractorOutput", "trackOutput"}) + private void assertInitialized() { + Assertions.checkStateNotNull(trackOutput); + Util.castNonNull(extractorOutput); + } + + /** Writes to the extractor's output. */ + private interface OutputWriter { + + /** + * Resets the writer. + * + * @param timeUs The new start position in microseconds. + */ + void reset(long timeUs); + + /** + * Initializes the writer. + * + * <p>Must be called once, before any calls to {@link #sampleData(ExtractorInput, long)}. + * + * @param dataStartPosition The byte position (inclusive) in the stream at which data starts. + * @param dataEndPosition The end position (exclusive) in the stream at which data ends. + * @throws ParserException If an error occurs initializing the writer. + */ + void init(int dataStartPosition, long dataEndPosition) throws ParserException; + + /** + * Consumes sample data from {@code input}, writing corresponding samples to the extractor's + * output. + * + * <p>Must not be called until after {@link #init(int, long)} has been called. + * + * @param input The input from which to read. + * @param bytesLeft The number of sample data bytes left to be read from the input. + * @return Whether the end of the sample data has been reached. + * @throws IOException If an error occurs reading from the input. + * @throws InterruptedException If the thread has been interrupted. + */ + boolean sampleData(ExtractorInput input, long bytesLeft) + throws IOException, InterruptedException; + } + + private static final class PassthroughOutputWriter implements OutputWriter { + + private final ExtractorOutput extractorOutput; + private final TrackOutput trackOutput; + private final WavHeader header; + private final Format format; + /** The target size of each output sample, in bytes. */ + private final int targetSampleSizeBytes; + + /** The time at which the writer was last {@link #reset}. */ + private long startTimeUs; + /** + * The number of bytes that have been written to {@link #trackOutput} but have yet to be + * included as part of a sample (i.e. the corresponding call to {@link + * TrackOutput#sampleMetadata} has yet to be made). + */ + private int pendingOutputBytes; + /** + * The total number of frames in samples that have been written to the trackOutput since the + * last call to {@link #reset}. + */ + private long outputFrameCount; + + public PassthroughOutputWriter( + ExtractorOutput extractorOutput, + TrackOutput trackOutput, + WavHeader header, + String mimeType, + @C.PcmEncoding int pcmEncoding) + throws ParserException { + this.extractorOutput = extractorOutput; + this.trackOutput = trackOutput; + this.header = header; + + int bytesPerFrame = header.numChannels * header.bitsPerSample / 8; + // Validate the header. Blocks are expected to correspond to single frames. + if (header.blockSize != bytesPerFrame) { + throw new ParserException( + "Expected block size: " + bytesPerFrame + "; got: " + header.blockSize); + } + + targetSampleSizeBytes = + Math.max(bytesPerFrame, header.frameRateHz * bytesPerFrame / TARGET_SAMPLES_PER_SECOND); + format = + Format.createAudioSampleFormat( + /* id= */ null, + mimeType, + /* codecs= */ null, + /* bitrate= */ header.frameRateHz * bytesPerFrame * 8, + /* maxInputSize= */ targetSampleSizeBytes, + header.numChannels, + header.frameRateHz, + pcmEncoding, + /* initializationData= */ null, + /* drmInitData= */ null, + /* selectionFlags= */ 0, + /* language= */ null); + } + + @Override + public void reset(long timeUs) { + startTimeUs = timeUs; + pendingOutputBytes = 0; + outputFrameCount = 0; + } + + @Override + public void init(int dataStartPosition, long dataEndPosition) { + extractorOutput.seekMap( + new WavSeekMap(header, /* framesPerBlock= */ 1, dataStartPosition, dataEndPosition)); + trackOutput.format(format); + } + + @Override + public boolean sampleData(ExtractorInput input, long bytesLeft) + throws IOException, InterruptedException { + // Write sample data until we've reached the target sample size, or the end of the data. + while (bytesLeft > 0 && pendingOutputBytes < targetSampleSizeBytes) { + int bytesToRead = (int) Math.min(targetSampleSizeBytes - pendingOutputBytes, bytesLeft); + int bytesAppended = trackOutput.sampleData(input, bytesToRead, true); + if (bytesAppended == RESULT_END_OF_INPUT) { + bytesLeft = 0; + } else { + pendingOutputBytes += bytesAppended; + bytesLeft -= bytesAppended; + } + } + + // Write the corresponding sample metadata. Samples must be a whole number of frames. It's + // possible that the number of pending output bytes is not a whole number of frames if the + // stream ended unexpectedly. + int bytesPerFrame = header.blockSize; + int pendingFrames = pendingOutputBytes / bytesPerFrame; + if (pendingFrames > 0) { + long timeUs = + startTimeUs + + Util.scaleLargeTimestamp( + outputFrameCount, C.MICROS_PER_SECOND, header.frameRateHz); + int size = pendingFrames * bytesPerFrame; + int offset = pendingOutputBytes - size; + trackOutput.sampleMetadata( + timeUs, C.BUFFER_FLAG_KEY_FRAME, size, offset, /* encryptionData= */ null); + outputFrameCount += pendingFrames; + pendingOutputBytes = offset; + } + + return bytesLeft <= 0; + } + } + + private static final class ImaAdPcmOutputWriter implements OutputWriter { + + private static final int[] INDEX_TABLE = { + -1, -1, -1, -1, 2, 4, 6, 8, -1, -1, -1, -1, 2, 4, 6, 8 + }; + + private static final int[] STEP_TABLE = { + 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, + 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279, 307, 337, 371, 408, + 449, 494, 544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, + 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, + 9493, 10442, 11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, + 32767 + }; + + private final ExtractorOutput extractorOutput; + private final TrackOutput trackOutput; + private final WavHeader header; + + /** Number of frames per block of the input (yet to be decoded) data. */ + private final int framesPerBlock; + /** Target for the input (yet to be decoded) data. */ + private final byte[] inputData; + /** Target for decoded (yet to be output) data. */ + private final ParsableByteArray decodedData; + /** The target size of each output sample, in frames. */ + private final int targetSampleSizeFrames; + /** The output format. */ + private final Format format; + + /** The number of pending bytes in {@link #inputData}. */ + private int pendingInputBytes; + /** The time at which the writer was last {@link #reset}. */ + private long startTimeUs; + /** + * The number of bytes that have been written to {@link #trackOutput} but have yet to be + * included as part of a sample (i.e. the corresponding call to {@link + * TrackOutput#sampleMetadata} has yet to be made). + */ + private int pendingOutputBytes; + /** + * The total number of frames in samples that have been written to the trackOutput since the + * last call to {@link #reset}. + */ + private long outputFrameCount; + + public ImaAdPcmOutputWriter( + ExtractorOutput extractorOutput, TrackOutput trackOutput, WavHeader header) + throws ParserException { + this.extractorOutput = extractorOutput; + this.trackOutput = trackOutput; + this.header = header; + targetSampleSizeFrames = Math.max(1, header.frameRateHz / TARGET_SAMPLES_PER_SECOND); + + ParsableByteArray scratch = new ParsableByteArray(header.extraData); + scratch.readLittleEndianUnsignedShort(); + framesPerBlock = scratch.readLittleEndianUnsignedShort(); + + int numChannels = header.numChannels; + // Validate the header. This calculation is defined in "Microsoft Multimedia Standards Update + // - New Multimedia Types and Data Techniques" (1994). See the "IMA ADPCM Wave Type" and "DVI + // ADPCM Wave Type" sections, and the calculation of wSamplesPerBlock in the latter. + int expectedFramesPerBlock = + (((header.blockSize - (4 * numChannels)) * 8) / (header.bitsPerSample * numChannels)) + 1; + if (framesPerBlock != expectedFramesPerBlock) { + throw new ParserException( + "Expected frames per block: " + expectedFramesPerBlock + "; got: " + framesPerBlock); + } + + // Calculate the number of blocks we'll need to decode to obtain an output sample of the + // target sample size, and allocate suitably sized buffers for input and decoded data. + int maxBlocksToDecode = Util.ceilDivide(targetSampleSizeFrames, framesPerBlock); + inputData = new byte[maxBlocksToDecode * header.blockSize]; + decodedData = + new ParsableByteArray( + maxBlocksToDecode * numOutputFramesToBytes(framesPerBlock, numChannels)); + + // Create the format. We calculate the bitrate of the data before decoding, since this is the + // bitrate of the stream itself. + int bitrate = header.frameRateHz * header.blockSize * 8 / framesPerBlock; + format = + Format.createAudioSampleFormat( + /* id= */ null, + MimeTypes.AUDIO_RAW, + /* codecs= */ null, + bitrate, + /* maxInputSize= */ numOutputFramesToBytes(targetSampleSizeFrames, numChannels), + header.numChannels, + header.frameRateHz, + C.ENCODING_PCM_16BIT, + /* initializationData= */ null, + /* drmInitData= */ null, + /* selectionFlags= */ 0, + /* language= */ null); + } + + @Override + public void reset(long timeUs) { + pendingInputBytes = 0; + startTimeUs = timeUs; + pendingOutputBytes = 0; + outputFrameCount = 0; + } + + @Override + public void init(int dataStartPosition, long dataEndPosition) { + extractorOutput.seekMap( + new WavSeekMap(header, framesPerBlock, dataStartPosition, dataEndPosition)); + trackOutput.format(format); + } + + @Override + public boolean sampleData(ExtractorInput input, long bytesLeft) + throws IOException, InterruptedException { + // Calculate the number of additional frames that we need on the output side to complete a + // sample of the target size. + int targetFramesRemaining = + targetSampleSizeFrames - numOutputBytesToFrames(pendingOutputBytes); + // Calculate the whole number of blocks that we need to decode to obtain this many frames. + int blocksToDecode = Util.ceilDivide(targetFramesRemaining, framesPerBlock); + int targetReadBytes = blocksToDecode * header.blockSize; + + // Read input data until we've reached the target number of blocks, or the end of the data. + boolean endOfSampleData = bytesLeft == 0; + while (!endOfSampleData && pendingInputBytes < targetReadBytes) { + int bytesToRead = (int) Math.min(targetReadBytes - pendingInputBytes, bytesLeft); + int bytesAppended = input.read(inputData, pendingInputBytes, bytesToRead); + if (bytesAppended == RESULT_END_OF_INPUT) { + endOfSampleData = true; + } else { + pendingInputBytes += bytesAppended; + } + } + + int pendingBlockCount = pendingInputBytes / header.blockSize; + if (pendingBlockCount > 0) { + // We have at least one whole block to decode. + decode(inputData, pendingBlockCount, decodedData); + pendingInputBytes -= pendingBlockCount * header.blockSize; + + // Write all of the decoded data to the track output. + int decodedDataSize = decodedData.limit(); + trackOutput.sampleData(decodedData, decodedDataSize); + pendingOutputBytes += decodedDataSize; + + // Output the next sample at the target size. + int pendingOutputFrames = numOutputBytesToFrames(pendingOutputBytes); + if (pendingOutputFrames >= targetSampleSizeFrames) { + writeSampleMetadata(targetSampleSizeFrames); + } + } + + // If we've reached the end of the data, we might need to output a final partial sample. + if (endOfSampleData) { + int pendingOutputFrames = numOutputBytesToFrames(pendingOutputBytes); + if (pendingOutputFrames > 0) { + writeSampleMetadata(pendingOutputFrames); + } + } + + return endOfSampleData; + } + + private void writeSampleMetadata(int sampleFrames) { + long timeUs = + startTimeUs + + Util.scaleLargeTimestamp(outputFrameCount, C.MICROS_PER_SECOND, header.frameRateHz); + int size = numOutputFramesToBytes(sampleFrames); + int offset = pendingOutputBytes - size; + trackOutput.sampleMetadata( + timeUs, C.BUFFER_FLAG_KEY_FRAME, size, offset, /* encryptionData= */ null); + outputFrameCount += sampleFrames; + pendingOutputBytes -= size; + } + + /** + * Decodes IMA ADPCM data to 16 bit PCM. + * + * @param input The input data to decode. + * @param blockCount The number of blocks to decode. + * @param output The output into which the decoded data will be written. + */ + private void decode(byte[] input, int blockCount, ParsableByteArray output) { + for (int blockIndex = 0; blockIndex < blockCount; blockIndex++) { + for (int channelIndex = 0; channelIndex < header.numChannels; channelIndex++) { + decodeBlockForChannel(input, blockIndex, channelIndex, output.data); + } + } + int decodedDataSize = numOutputFramesToBytes(framesPerBlock * blockCount); + output.reset(decodedDataSize); + } + + private void decodeBlockForChannel( + byte[] input, int blockIndex, int channelIndex, byte[] output) { + int blockSize = header.blockSize; + int numChannels = header.numChannels; + + // The input data consists for a four byte header [Ci] for each of the N channels, followed + // by interleaved data segments [Ci-DATAj], each of which are four bytes long. + // + // [C1][C2]...[CN] [C1-Data0][C2-Data0]...[CN-Data0] [C1-Data1][C2-Data1]...[CN-Data1] etc + // + // Compute the start indices for the [Ci] and [Ci-Data0] for the current channel, as well as + // the number of data bytes for the channel in the block. + int blockStartIndex = blockIndex * blockSize; + int headerStartIndex = blockStartIndex + channelIndex * 4; + int dataStartIndex = headerStartIndex + numChannels * 4; + int dataSizeBytes = blockSize / numChannels - 4; + + // Decode initialization. Casting to a short is necessary for the most significant bit to be + // treated as -2^15 rather than 2^15. + int predictedSample = + (short) (((input[headerStartIndex + 1] & 0xFF) << 8) | (input[headerStartIndex] & 0xFF)); + int stepIndex = Math.min(input[headerStartIndex + 2] & 0xFF, 88); + int step = STEP_TABLE[stepIndex]; + + // Output the initial 16 bit PCM sample from the header. + int outputIndex = (blockIndex * framesPerBlock * numChannels + channelIndex) * 2; + output[outputIndex] = (byte) (predictedSample & 0xFF); + output[outputIndex + 1] = (byte) (predictedSample >> 8); + + // We examine each data byte twice during decode. + for (int i = 0; i < dataSizeBytes * 2; i++) { + int dataSegmentIndex = i / 8; + int dataSegmentOffset = (i / 2) % 4; + int dataIndex = dataStartIndex + (dataSegmentIndex * numChannels * 4) + dataSegmentOffset; + + int originalSample = input[dataIndex] & 0xFF; + if (i % 2 == 0) { + originalSample &= 0x0F; // Bottom four bits. + } else { + originalSample >>= 4; // Top four bits. + } + + int delta = originalSample & 0x07; + int difference = ((2 * delta + 1) * step) >> 3; + + if ((originalSample & 0x08) != 0) { + difference = -difference; + } + + predictedSample += difference; + predictedSample = Util.constrainValue(predictedSample, /* min= */ -32768, /* max= */ 32767); + + // Output the next 16 bit PCM sample to the correct position in the output. + outputIndex += 2 * numChannels; + output[outputIndex] = (byte) (predictedSample & 0xFF); + output[outputIndex + 1] = (byte) (predictedSample >> 8); + + stepIndex += INDEX_TABLE[originalSample]; + stepIndex = Util.constrainValue(stepIndex, /* min= */ 0, /* max= */ STEP_TABLE.length - 1); + step = STEP_TABLE[stepIndex]; + } + } + + private int numOutputBytesToFrames(int bytes) { + return bytes / (2 * header.numChannels); + } + + private int numOutputFramesToBytes(int frames) { + return numOutputFramesToBytes(frames, header.numChannels); + } + + private static int numOutputFramesToBytes(int frames, int numChannels) { + return frames * 2 * numChannels; + } + } +} |