diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/flv/FlvExtractor.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/flv/FlvExtractor.java | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/flv/FlvExtractor.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/flv/FlvExtractor.java new file mode 100644 index 0000000000..a7438b190f --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/flv/FlvExtractor.java @@ -0,0 +1,308 @@ +/* + * 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.flv; + +import androidx.annotation.IntDef; +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +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.SeekMap; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray; +import java.io.IOException; +import java.lang.annotation.Documented; +import java.lang.annotation.Retention; +import java.lang.annotation.RetentionPolicy; + +/** + * Extracts data from the FLV container format. + */ +public final class FlvExtractor implements Extractor { + + /** Factory for {@link FlvExtractor} instances. */ + public static final ExtractorsFactory FACTORY = () -> new Extractor[] {new FlvExtractor()}; + + /** Extractor states. */ + @Documented + @Retention(RetentionPolicy.SOURCE) + @IntDef({ + STATE_READING_FLV_HEADER, + STATE_SKIPPING_TO_TAG_HEADER, + STATE_READING_TAG_HEADER, + STATE_READING_TAG_DATA + }) + private @interface States {} + + private static final int STATE_READING_FLV_HEADER = 1; + private static final int STATE_SKIPPING_TO_TAG_HEADER = 2; + private static final int STATE_READING_TAG_HEADER = 3; + private static final int STATE_READING_TAG_DATA = 4; + + // Header sizes. + private static final int FLV_HEADER_SIZE = 9; + private static final int FLV_TAG_HEADER_SIZE = 11; + + // Tag types. + private static final int TAG_TYPE_AUDIO = 8; + private static final int TAG_TYPE_VIDEO = 9; + private static final int TAG_TYPE_SCRIPT_DATA = 18; + + // FLV container identifier. + private static final int FLV_TAG = 0x00464c56; + + private final ParsableByteArray scratch; + private final ParsableByteArray headerBuffer; + private final ParsableByteArray tagHeaderBuffer; + private final ParsableByteArray tagData; + private final ScriptTagPayloadReader metadataReader; + + private ExtractorOutput extractorOutput; + private @States int state; + private boolean outputFirstSample; + private long mediaTagTimestampOffsetUs; + private int bytesToNextTagHeader; + private int tagType; + private int tagDataSize; + private long tagTimestampUs; + private boolean outputSeekMap; + private AudioTagPayloadReader audioReader; + private VideoTagPayloadReader videoReader; + + public FlvExtractor() { + scratch = new ParsableByteArray(4); + headerBuffer = new ParsableByteArray(FLV_HEADER_SIZE); + tagHeaderBuffer = new ParsableByteArray(FLV_TAG_HEADER_SIZE); + tagData = new ParsableByteArray(); + metadataReader = new ScriptTagPayloadReader(); + state = STATE_READING_FLV_HEADER; + } + + @Override + public boolean sniff(ExtractorInput input) throws IOException, InterruptedException { + // Check if file starts with "FLV" tag + input.peekFully(scratch.data, 0, 3); + scratch.setPosition(0); + if (scratch.readUnsignedInt24() != FLV_TAG) { + return false; + } + + // Checking reserved flags are set to 0 + input.peekFully(scratch.data, 0, 2); + scratch.setPosition(0); + if ((scratch.readUnsignedShort() & 0xFA) != 0) { + return false; + } + + // Read data offset + input.peekFully(scratch.data, 0, 4); + scratch.setPosition(0); + int dataOffset = scratch.readInt(); + + input.resetPeekPosition(); + input.advancePeekPosition(dataOffset); + + // Checking first "previous tag size" is set to 0 + input.peekFully(scratch.data, 0, 4); + scratch.setPosition(0); + + return scratch.readInt() == 0; + } + + @Override + public void init(ExtractorOutput output) { + this.extractorOutput = output; + } + + @Override + public void seek(long position, long timeUs) { + state = STATE_READING_FLV_HEADER; + outputFirstSample = false; + bytesToNextTagHeader = 0; + } + + @Override + public void release() { + // Do nothing + } + + @Override + public int read(ExtractorInput input, PositionHolder seekPosition) throws IOException, + InterruptedException { + while (true) { + switch (state) { + case STATE_READING_FLV_HEADER: + if (!readFlvHeader(input)) { + return RESULT_END_OF_INPUT; + } + break; + case STATE_SKIPPING_TO_TAG_HEADER: + skipToTagHeader(input); + break; + case STATE_READING_TAG_HEADER: + if (!readTagHeader(input)) { + return RESULT_END_OF_INPUT; + } + break; + case STATE_READING_TAG_DATA: + if (readTagData(input)) { + return RESULT_CONTINUE; + } + break; + default: + // Never happens. + throw new IllegalStateException(); + } + } + } + + /** + * Reads an FLV container header from the provided {@link ExtractorInput}. + * + * @param input The {@link ExtractorInput} from which to read. + * @return True if header was read successfully. False if the end of stream was reached. + * @throws IOException If an error occurred reading or parsing data from the source. + * @throws InterruptedException If the thread was interrupted. + */ + private boolean readFlvHeader(ExtractorInput input) throws IOException, InterruptedException { + if (!input.readFully(headerBuffer.data, 0, FLV_HEADER_SIZE, true)) { + // We've reached the end of the stream. + return false; + } + + headerBuffer.setPosition(0); + headerBuffer.skipBytes(4); + int flags = headerBuffer.readUnsignedByte(); + boolean hasAudio = (flags & 0x04) != 0; + boolean hasVideo = (flags & 0x01) != 0; + if (hasAudio && audioReader == null) { + audioReader = new AudioTagPayloadReader( + extractorOutput.track(TAG_TYPE_AUDIO, C.TRACK_TYPE_AUDIO)); + } + if (hasVideo && videoReader == null) { + videoReader = new VideoTagPayloadReader( + extractorOutput.track(TAG_TYPE_VIDEO, C.TRACK_TYPE_VIDEO)); + } + extractorOutput.endTracks(); + + // We need to skip any additional content in the FLV header, plus the 4 byte previous tag size. + bytesToNextTagHeader = headerBuffer.readInt() - FLV_HEADER_SIZE + 4; + state = STATE_SKIPPING_TO_TAG_HEADER; + return true; + } + + /** + * Skips over data to reach the next tag header. + * + * @param input The {@link ExtractorInput} from which to read. + * @throws IOException If an error occurred skipping data from the source. + * @throws InterruptedException If the thread was interrupted. + */ + private void skipToTagHeader(ExtractorInput input) throws IOException, InterruptedException { + input.skipFully(bytesToNextTagHeader); + bytesToNextTagHeader = 0; + state = STATE_READING_TAG_HEADER; + } + + /** + * Reads a tag header from the provided {@link ExtractorInput}. + * + * @param input The {@link ExtractorInput} from which to read. + * @return True if tag header was read successfully. Otherwise, false. + * @throws IOException If an error occurred reading or parsing data from the source. + * @throws InterruptedException If the thread was interrupted. + */ + private boolean readTagHeader(ExtractorInput input) throws IOException, InterruptedException { + if (!input.readFully(tagHeaderBuffer.data, 0, FLV_TAG_HEADER_SIZE, true)) { + // We've reached the end of the stream. + return false; + } + + tagHeaderBuffer.setPosition(0); + tagType = tagHeaderBuffer.readUnsignedByte(); + tagDataSize = tagHeaderBuffer.readUnsignedInt24(); + tagTimestampUs = tagHeaderBuffer.readUnsignedInt24(); + tagTimestampUs = ((tagHeaderBuffer.readUnsignedByte() << 24) | tagTimestampUs) * 1000L; + tagHeaderBuffer.skipBytes(3); // streamId + state = STATE_READING_TAG_DATA; + return true; + } + + /** + * Reads the body of a tag from the provided {@link ExtractorInput}. + * + * @param input The {@link ExtractorInput} from which to read. + * @return True if the data was consumed by a reader. False if it was skipped. + * @throws IOException If an error occurred reading or parsing data from the source. + * @throws InterruptedException If the thread was interrupted. + */ + private boolean readTagData(ExtractorInput input) throws IOException, InterruptedException { + boolean wasConsumed = true; + boolean wasSampleOutput = false; + long timestampUs = getCurrentTimestampUs(); + if (tagType == TAG_TYPE_AUDIO && audioReader != null) { + ensureReadyForMediaOutput(); + wasSampleOutput = audioReader.consume(prepareTagData(input), timestampUs); + } else if (tagType == TAG_TYPE_VIDEO && videoReader != null) { + ensureReadyForMediaOutput(); + wasSampleOutput = videoReader.consume(prepareTagData(input), timestampUs); + } else if (tagType == TAG_TYPE_SCRIPT_DATA && !outputSeekMap) { + wasSampleOutput = metadataReader.consume(prepareTagData(input), timestampUs); + long durationUs = metadataReader.getDurationUs(); + if (durationUs != C.TIME_UNSET) { + extractorOutput.seekMap(new SeekMap.Unseekable(durationUs)); + outputSeekMap = true; + } + } else { + input.skipFully(tagDataSize); + wasConsumed = false; + } + if (!outputFirstSample && wasSampleOutput) { + outputFirstSample = true; + mediaTagTimestampOffsetUs = + metadataReader.getDurationUs() == C.TIME_UNSET ? -tagTimestampUs : 0; + } + bytesToNextTagHeader = 4; // There's a 4 byte previous tag size before the next header. + state = STATE_SKIPPING_TO_TAG_HEADER; + return wasConsumed; + } + + private ParsableByteArray prepareTagData(ExtractorInput input) throws IOException, + InterruptedException { + if (tagDataSize > tagData.capacity()) { + tagData.reset(new byte[Math.max(tagData.capacity() * 2, tagDataSize)], 0); + } else { + tagData.setPosition(0); + } + tagData.setLimit(tagDataSize); + input.readFully(tagData.data, 0, tagDataSize); + return tagData; + } + + private void ensureReadyForMediaOutput() { + if (!outputSeekMap) { + extractorOutput.seekMap(new SeekMap.Unseekable(C.TIME_UNSET)); + outputSeekMap = true; + } + } + + private long getCurrentTimestampUs() { + return outputFirstSample + ? (mediaTagTimestampOffsetUs + tagTimestampUs) + : (metadataReader.getDurationUs() == C.TIME_UNSET ? 0 : tagTimestampUs); + } +} |