diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/FlacMetadataReader.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/FlacMetadataReader.java | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/FlacMetadataReader.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/FlacMetadataReader.java new file mode 100644 index 0000000000..c5413cf459 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/FlacMetadataReader.java @@ -0,0 +1,312 @@ +/* + * Copyright (C) 2019 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; + +import androidx.annotation.Nullable; +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +import org.mozilla.thirdparty.com.google.android.exoplayer2.ParserException; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.VorbisUtil.CommentHeader; +import org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.Metadata; +import org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.flac.PictureFrame; +import org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.id3.Id3Decoder; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.FlacConstants; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.FlacStreamMetadata; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableBitArray; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray; +import java.io.IOException; +import java.nio.charset.Charset; +import java.util.Arrays; +import java.util.Collections; +import java.util.List; + +/** + * Reads and peeks FLAC stream metadata elements according to the <a + * href="https://xiph.org/flac/format.html">FLAC format specification</a>. + */ +public final class FlacMetadataReader { + + /** Holds a {@link FlacStreamMetadata}. */ + public static final class FlacStreamMetadataHolder { + /** The FLAC stream metadata. */ + @Nullable public FlacStreamMetadata flacStreamMetadata; + + public FlacStreamMetadataHolder(@Nullable FlacStreamMetadata flacStreamMetadata) { + this.flacStreamMetadata = flacStreamMetadata; + } + } + + private static final int STREAM_MARKER = 0x664C6143; // ASCII for "fLaC" + private static final int SYNC_CODE = 0x3FFE; + private static final int SEEK_POINT_SIZE = 18; + + /** + * Peeks ID3 Data. + * + * @param input Input stream to peek the ID3 data from. + * @param parseData Whether to parse the ID3 frames. + * @return The parsed ID3 data, or {@code null} if there is no such data or if {@code parseData} + * is {@code false}. + * @throws IOException If peeking from the input fails. In this case, there is no guarantee on the + * peek position. + * @throws InterruptedException If interrupted while peeking from input. In this case, there is no + * guarantee on the peek position. + */ + @Nullable + public static Metadata peekId3Metadata(ExtractorInput input, boolean parseData) + throws IOException, InterruptedException { + @Nullable + Id3Decoder.FramePredicate id3FramePredicate = parseData ? null : Id3Decoder.NO_FRAMES_PREDICATE; + @Nullable Metadata id3Metadata = new Id3Peeker().peekId3Data(input, id3FramePredicate); + return id3Metadata == null || id3Metadata.length() == 0 ? null : id3Metadata; + } + + /** + * Peeks the FLAC stream marker. + * + * @param input Input stream to peek the stream marker from. + * @return Whether the data peeked is the FLAC stream marker. + * @throws IOException If peeking from the input fails. In this case, the peek position is left + * unchanged. + * @throws InterruptedException If interrupted while peeking from input. In this case, the peek + * position is left unchanged. + */ + public static boolean checkAndPeekStreamMarker(ExtractorInput input) + throws IOException, InterruptedException { + ParsableByteArray scratch = new ParsableByteArray(FlacConstants.STREAM_MARKER_SIZE); + input.peekFully(scratch.data, 0, FlacConstants.STREAM_MARKER_SIZE); + return scratch.readUnsignedInt() == STREAM_MARKER; + } + + /** + * Reads ID3 Data. + * + * <p>If no exception is thrown, the peek position of {@code input} is aligned with the read + * position. + * + * @param input Input stream to read the ID3 data from. + * @param parseData Whether to parse the ID3 frames. + * @return The parsed ID3 data, or {@code null} if there is no such data or if {@code parseData} + * is {@code false}. + * @throws IOException If reading from the input fails. In this case, the read position is left + * unchanged and there is no guarantee on the peek position. + * @throws InterruptedException If interrupted while reading from input. In this case, the read + * position is left unchanged and there is no guarantee on the peek position. + */ + @Nullable + public static Metadata readId3Metadata(ExtractorInput input, boolean parseData) + throws IOException, InterruptedException { + input.resetPeekPosition(); + long startingPeekPosition = input.getPeekPosition(); + @Nullable Metadata id3Metadata = peekId3Metadata(input, parseData); + int peekedId3Bytes = (int) (input.getPeekPosition() - startingPeekPosition); + input.skipFully(peekedId3Bytes); + return id3Metadata; + } + + /** + * Reads the FLAC stream marker. + * + * @param input Input stream to read the stream marker from. + * @throws ParserException If an error occurs parsing the stream marker. In this case, the + * position of {@code input} is advanced by {@link FlacConstants#STREAM_MARKER_SIZE} bytes. + * @throws IOException If reading from the input fails. In this case, the position is left + * unchanged. + * @throws InterruptedException If interrupted while reading from input. In this case, the + * position is left unchanged. + */ + public static void readStreamMarker(ExtractorInput input) + throws IOException, InterruptedException { + ParsableByteArray scratch = new ParsableByteArray(FlacConstants.STREAM_MARKER_SIZE); + input.readFully(scratch.data, 0, FlacConstants.STREAM_MARKER_SIZE); + if (scratch.readUnsignedInt() != STREAM_MARKER) { + throw new ParserException("Failed to read FLAC stream marker."); + } + } + + /** + * Reads one FLAC metadata block. + * + * <p>If no exception is thrown, the peek position of {@code input} is aligned with the read + * position. + * + * @param input Input stream to read the metadata block from (header included). + * @param metadataHolder A holder for the metadata read. If the stream info block (which must be + * the first metadata block) is read, the holder contains a new instance representing the + * stream info data. If the block read is a Vorbis comment block or a picture block, the + * holder contains a copy of the existing stream metadata with the corresponding metadata + * added. Otherwise, the metadata in the holder is unchanged. + * @return Whether the block read is the last metadata block. + * @throws IllegalArgumentException If the block read is not a stream info block and the metadata + * in {@code metadataHolder} is {@code null}. In this case, the read position will be at the + * start of a metadata block and there is no guarantee on the peek position. + * @throws IOException If reading from the input fails. In this case, the read position will be at + * the start of a metadata block and there is no guarantee on the peek position. + * @throws InterruptedException If interrupted while reading from input. In this case, the read + * position will be at the start of a metadata block and there is no guarantee on the peek + * position. + */ + public static boolean readMetadataBlock( + ExtractorInput input, FlacStreamMetadataHolder metadataHolder) + throws IOException, InterruptedException { + input.resetPeekPosition(); + ParsableBitArray scratch = new ParsableBitArray(new byte[4]); + input.peekFully(scratch.data, 0, FlacConstants.METADATA_BLOCK_HEADER_SIZE); + + boolean isLastMetadataBlock = scratch.readBit(); + int type = scratch.readBits(7); + int length = FlacConstants.METADATA_BLOCK_HEADER_SIZE + scratch.readBits(24); + if (type == FlacConstants.METADATA_TYPE_STREAM_INFO) { + metadataHolder.flacStreamMetadata = readStreamInfoBlock(input); + } else { + FlacStreamMetadata flacStreamMetadata = metadataHolder.flacStreamMetadata; + if (flacStreamMetadata == null) { + throw new IllegalArgumentException(); + } + if (type == FlacConstants.METADATA_TYPE_SEEK_TABLE) { + FlacStreamMetadata.SeekTable seekTable = readSeekTableMetadataBlock(input, length); + metadataHolder.flacStreamMetadata = flacStreamMetadata.copyWithSeekTable(seekTable); + } else if (type == FlacConstants.METADATA_TYPE_VORBIS_COMMENT) { + List<String> vorbisComments = readVorbisCommentMetadataBlock(input, length); + metadataHolder.flacStreamMetadata = + flacStreamMetadata.copyWithVorbisComments(vorbisComments); + } else if (type == FlacConstants.METADATA_TYPE_PICTURE) { + PictureFrame pictureFrame = readPictureMetadataBlock(input, length); + metadataHolder.flacStreamMetadata = + flacStreamMetadata.copyWithPictureFrames(Collections.singletonList(pictureFrame)); + } else { + input.skipFully(length); + } + } + + return isLastMetadataBlock; + } + + /** + * Reads a FLAC seek table metadata block. + * + * <p>The position of {@code data} is moved to the byte following the seek table metadata block + * (placeholder points included). + * + * @param data The array to read the data from, whose position must correspond to the seek table + * metadata block (header included). + * @return The seek table, without the placeholder points. + */ + public static FlacStreamMetadata.SeekTable readSeekTableMetadataBlock(ParsableByteArray data) { + data.skipBytes(1); + int length = data.readUnsignedInt24(); + + long seekTableEndPosition = data.getPosition() + length; + int seekPointCount = length / SEEK_POINT_SIZE; + long[] pointSampleNumbers = new long[seekPointCount]; + long[] pointOffsets = new long[seekPointCount]; + for (int i = 0; i < seekPointCount; i++) { + // The sample number is expected to fit in a signed long, except if it is a placeholder, in + // which case its value is -1. + long sampleNumber = data.readLong(); + if (sampleNumber == -1) { + pointSampleNumbers = Arrays.copyOf(pointSampleNumbers, i); + pointOffsets = Arrays.copyOf(pointOffsets, i); + break; + } + pointSampleNumbers[i] = sampleNumber; + pointOffsets[i] = data.readLong(); + data.skipBytes(2); + } + + data.skipBytes((int) (seekTableEndPosition - data.getPosition())); + return new FlacStreamMetadata.SeekTable(pointSampleNumbers, pointOffsets); + } + + /** + * Returns the frame start marker, consisting of the 2 first bytes of the first frame. + * + * <p>The read position of {@code input} is left unchanged and the peek position is aligned with + * the read position. + * + * @param input Input stream to get the start marker from (starting from the read position). + * @return The frame start marker (which must be the same for all the frames in the stream). + * @throws ParserException If an error occurs parsing the frame start marker. + * @throws IOException If peeking from the input fails. + * @throws InterruptedException If interrupted while peeking from input. + */ + public static int getFrameStartMarker(ExtractorInput input) + throws IOException, InterruptedException { + input.resetPeekPosition(); + ParsableByteArray scratch = new ParsableByteArray(2); + input.peekFully(scratch.data, 0, 2); + + int frameStartMarker = scratch.readUnsignedShort(); + int syncCode = frameStartMarker >> 2; + if (syncCode != SYNC_CODE) { + input.resetPeekPosition(); + throw new ParserException("First frame does not start with sync code."); + } + + input.resetPeekPosition(); + return frameStartMarker; + } + + private static FlacStreamMetadata readStreamInfoBlock(ExtractorInput input) + throws IOException, InterruptedException { + byte[] scratchData = new byte[FlacConstants.STREAM_INFO_BLOCK_SIZE]; + input.readFully(scratchData, 0, FlacConstants.STREAM_INFO_BLOCK_SIZE); + return new FlacStreamMetadata( + scratchData, /* offset= */ FlacConstants.METADATA_BLOCK_HEADER_SIZE); + } + + private static FlacStreamMetadata.SeekTable readSeekTableMetadataBlock( + ExtractorInput input, int length) throws IOException, InterruptedException { + ParsableByteArray scratch = new ParsableByteArray(length); + input.readFully(scratch.data, 0, length); + return readSeekTableMetadataBlock(scratch); + } + + private static List<String> readVorbisCommentMetadataBlock(ExtractorInput input, int length) + throws IOException, InterruptedException { + ParsableByteArray scratch = new ParsableByteArray(length); + input.readFully(scratch.data, 0, length); + scratch.skipBytes(FlacConstants.METADATA_BLOCK_HEADER_SIZE); + CommentHeader commentHeader = + VorbisUtil.readVorbisCommentHeader( + scratch, /* hasMetadataHeader= */ false, /* hasFramingBit= */ false); + return Arrays.asList(commentHeader.comments); + } + + private static PictureFrame readPictureMetadataBlock(ExtractorInput input, int length) + throws IOException, InterruptedException { + ParsableByteArray scratch = new ParsableByteArray(length); + input.readFully(scratch.data, 0, length); + scratch.skipBytes(FlacConstants.METADATA_BLOCK_HEADER_SIZE); + + int pictureType = scratch.readInt(); + int mimeTypeLength = scratch.readInt(); + String mimeType = scratch.readString(mimeTypeLength, Charset.forName(C.ASCII_NAME)); + int descriptionLength = scratch.readInt(); + String description = scratch.readString(descriptionLength); + int width = scratch.readInt(); + int height = scratch.readInt(); + int depth = scratch.readInt(); + int colors = scratch.readInt(); + int pictureDataLength = scratch.readInt(); + byte[] pictureData = new byte[pictureDataLength]; + scratch.readBytes(pictureData, 0, pictureDataLength); + + return new PictureFrame( + pictureType, mimeType, description, width, height, depth, colors, pictureData); + } + + private FlacMetadataReader() {} +} |