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Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Mp4Extractor.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Mp4Extractor.java | 824 |
1 files changed, 824 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Mp4Extractor.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Mp4Extractor.java new file mode 100644 index 0000000000..254cad1eb1 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Mp4Extractor.java @@ -0,0 +1,824 @@ +/* + * 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.mp4; + +import androidx.annotation.IntDef; +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.Ac4Util; +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.GaplessInfoHolder; +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.extractor.SeekPoint; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.TrackOutput; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.mp4.Atom.ContainerAtom; +import org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.Metadata; +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.NalUnitUtil; +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; +import java.util.ArrayDeque; +import java.util.ArrayList; +import java.util.List; + +/** + * Extracts data from the MP4 container format. + */ +public final class Mp4Extractor implements Extractor, SeekMap { + + /** Factory for {@link Mp4Extractor} instances. */ + public static final ExtractorsFactory FACTORY = () -> new Extractor[] {new Mp4Extractor()}; + + /** + * Flags controlling the behavior of the extractor. Possible flag value is {@link + * #FLAG_WORKAROUND_IGNORE_EDIT_LISTS}. + */ + @Documented + @Retention(RetentionPolicy.SOURCE) + @IntDef( + flag = true, + value = {FLAG_WORKAROUND_IGNORE_EDIT_LISTS}) + public @interface Flags {} + /** + * Flag to ignore any edit lists in the stream. + */ + public static final int FLAG_WORKAROUND_IGNORE_EDIT_LISTS = 1; + + /** Parser states. */ + @Documented + @Retention(RetentionPolicy.SOURCE) + @IntDef({STATE_READING_ATOM_HEADER, STATE_READING_ATOM_PAYLOAD, STATE_READING_SAMPLE}) + private @interface State {} + + private static final int STATE_READING_ATOM_HEADER = 0; + private static final int STATE_READING_ATOM_PAYLOAD = 1; + private static final int STATE_READING_SAMPLE = 2; + + /** Brand stored in the ftyp atom for QuickTime media. */ + private static final int BRAND_QUICKTIME = 0x71742020; + + /** + * When seeking within the source, if the offset is greater than or equal to this value (or the + * offset is negative), the source will be reloaded. + */ + private static final long RELOAD_MINIMUM_SEEK_DISTANCE = 256 * 1024; + + /** + * For poorly interleaved streams, the maximum byte difference one track is allowed to be read + * ahead before the source will be reloaded at a new position to read another track. + */ + private static final long MAXIMUM_READ_AHEAD_BYTES_STREAM = 10 * 1024 * 1024; + + private final @Flags int flags; + + // Temporary arrays. + private final ParsableByteArray nalStartCode; + private final ParsableByteArray nalLength; + private final ParsableByteArray scratch; + + private final ParsableByteArray atomHeader; + private final ArrayDeque<ContainerAtom> containerAtoms; + + @State private int parserState; + private int atomType; + private long atomSize; + private int atomHeaderBytesRead; + private ParsableByteArray atomData; + + private int sampleTrackIndex; + private int sampleBytesRead; + private int sampleBytesWritten; + private int sampleCurrentNalBytesRemaining; + + // Extractor outputs. + private ExtractorOutput extractorOutput; + private Mp4Track[] tracks; + private long[][] accumulatedSampleSizes; + private int firstVideoTrackIndex; + private long durationUs; + private boolean isQuickTime; + + /** + * Creates a new extractor for unfragmented MP4 streams. + */ + public Mp4Extractor() { + this(0); + } + + /** + * Creates a new extractor for unfragmented MP4 streams, using the specified flags to control the + * extractor's behavior. + * + * @param flags Flags that control the extractor's behavior. + */ + public Mp4Extractor(@Flags int flags) { + this.flags = flags; + atomHeader = new ParsableByteArray(Atom.LONG_HEADER_SIZE); + containerAtoms = new ArrayDeque<>(); + nalStartCode = new ParsableByteArray(NalUnitUtil.NAL_START_CODE); + nalLength = new ParsableByteArray(4); + scratch = new ParsableByteArray(); + sampleTrackIndex = C.INDEX_UNSET; + } + + @Override + public boolean sniff(ExtractorInput input) throws IOException, InterruptedException { + return Sniffer.sniffUnfragmented(input); + } + + @Override + public void init(ExtractorOutput output) { + extractorOutput = output; + } + + @Override + public void seek(long position, long timeUs) { + containerAtoms.clear(); + atomHeaderBytesRead = 0; + sampleTrackIndex = C.INDEX_UNSET; + sampleBytesRead = 0; + sampleBytesWritten = 0; + sampleCurrentNalBytesRemaining = 0; + if (position == 0) { + enterReadingAtomHeaderState(); + } else if (tracks != null) { + updateSampleIndices(timeUs); + } + } + + @Override + public void release() { + // Do nothing + } + + @Override + public int read(ExtractorInput input, PositionHolder seekPosition) + throws IOException, InterruptedException { + while (true) { + switch (parserState) { + case STATE_READING_ATOM_HEADER: + if (!readAtomHeader(input)) { + return RESULT_END_OF_INPUT; + } + break; + case STATE_READING_ATOM_PAYLOAD: + if (readAtomPayload(input, seekPosition)) { + return RESULT_SEEK; + } + break; + case STATE_READING_SAMPLE: + return readSample(input, seekPosition); + default: + throw new IllegalStateException(); + } + } + } + + // SeekMap implementation. + + @Override + public boolean isSeekable() { + return true; + } + + @Override + public long getDurationUs() { + return durationUs; + } + + @Override + public SeekPoints getSeekPoints(long timeUs) { + if (tracks.length == 0) { + return new SeekPoints(SeekPoint.START); + } + + long firstTimeUs; + long firstOffset; + long secondTimeUs = C.TIME_UNSET; + long secondOffset = C.POSITION_UNSET; + + // If we have a video track, use it to establish one or two seek points. + if (firstVideoTrackIndex != C.INDEX_UNSET) { + TrackSampleTable sampleTable = tracks[firstVideoTrackIndex].sampleTable; + int sampleIndex = getSynchronizationSampleIndex(sampleTable, timeUs); + if (sampleIndex == C.INDEX_UNSET) { + return new SeekPoints(SeekPoint.START); + } + long sampleTimeUs = sampleTable.timestampsUs[sampleIndex]; + firstTimeUs = sampleTimeUs; + firstOffset = sampleTable.offsets[sampleIndex]; + if (sampleTimeUs < timeUs && sampleIndex < sampleTable.sampleCount - 1) { + int secondSampleIndex = sampleTable.getIndexOfLaterOrEqualSynchronizationSample(timeUs); + if (secondSampleIndex != C.INDEX_UNSET && secondSampleIndex != sampleIndex) { + secondTimeUs = sampleTable.timestampsUs[secondSampleIndex]; + secondOffset = sampleTable.offsets[secondSampleIndex]; + } + } + } else { + firstTimeUs = timeUs; + firstOffset = Long.MAX_VALUE; + } + + // Take into account other tracks. + for (int i = 0; i < tracks.length; i++) { + if (i != firstVideoTrackIndex) { + TrackSampleTable sampleTable = tracks[i].sampleTable; + firstOffset = maybeAdjustSeekOffset(sampleTable, firstTimeUs, firstOffset); + if (secondTimeUs != C.TIME_UNSET) { + secondOffset = maybeAdjustSeekOffset(sampleTable, secondTimeUs, secondOffset); + } + } + } + + SeekPoint firstSeekPoint = new SeekPoint(firstTimeUs, firstOffset); + if (secondTimeUs == C.TIME_UNSET) { + return new SeekPoints(firstSeekPoint); + } else { + SeekPoint secondSeekPoint = new SeekPoint(secondTimeUs, secondOffset); + return new SeekPoints(firstSeekPoint, secondSeekPoint); + } + } + + // Private methods. + + private void enterReadingAtomHeaderState() { + parserState = STATE_READING_ATOM_HEADER; + atomHeaderBytesRead = 0; + } + + private boolean readAtomHeader(ExtractorInput input) throws IOException, InterruptedException { + if (atomHeaderBytesRead == 0) { + // Read the standard length atom header. + if (!input.readFully(atomHeader.data, 0, Atom.HEADER_SIZE, true)) { + return false; + } + atomHeaderBytesRead = Atom.HEADER_SIZE; + atomHeader.setPosition(0); + atomSize = atomHeader.readUnsignedInt(); + atomType = atomHeader.readInt(); + } + + if (atomSize == Atom.DEFINES_LARGE_SIZE) { + // Read the large size. + int headerBytesRemaining = Atom.LONG_HEADER_SIZE - Atom.HEADER_SIZE; + input.readFully(atomHeader.data, Atom.HEADER_SIZE, headerBytesRemaining); + atomHeaderBytesRead += headerBytesRemaining; + atomSize = atomHeader.readUnsignedLongToLong(); + } else if (atomSize == Atom.EXTENDS_TO_END_SIZE) { + // The atom extends to the end of the file. Note that if the atom is within a container we can + // work out its size even if the input length is unknown. + long endPosition = input.getLength(); + if (endPosition == C.LENGTH_UNSET && !containerAtoms.isEmpty()) { + endPosition = containerAtoms.peek().endPosition; + } + if (endPosition != C.LENGTH_UNSET) { + atomSize = endPosition - input.getPosition() + atomHeaderBytesRead; + } + } + + if (atomSize < atomHeaderBytesRead) { + throw new ParserException("Atom size less than header length (unsupported)."); + } + + if (shouldParseContainerAtom(atomType)) { + long endPosition = input.getPosition() + atomSize - atomHeaderBytesRead; + if (atomSize != atomHeaderBytesRead && atomType == Atom.TYPE_meta) { + maybeSkipRemainingMetaAtomHeaderBytes(input); + } + containerAtoms.push(new ContainerAtom(atomType, endPosition)); + if (atomSize == atomHeaderBytesRead) { + processAtomEnded(endPosition); + } else { + // Start reading the first child atom. + enterReadingAtomHeaderState(); + } + } else if (shouldParseLeafAtom(atomType)) { + // We don't support parsing of leaf atoms that define extended atom sizes, or that have + // lengths greater than Integer.MAX_VALUE. + Assertions.checkState(atomHeaderBytesRead == Atom.HEADER_SIZE); + Assertions.checkState(atomSize <= Integer.MAX_VALUE); + atomData = new ParsableByteArray((int) atomSize); + System.arraycopy(atomHeader.data, 0, atomData.data, 0, Atom.HEADER_SIZE); + parserState = STATE_READING_ATOM_PAYLOAD; + } else { + atomData = null; + parserState = STATE_READING_ATOM_PAYLOAD; + } + + return true; + } + + /** + * Processes the atom payload. If {@link #atomData} is null and the size is at or above the + * threshold {@link #RELOAD_MINIMUM_SEEK_DISTANCE}, {@code true} is returned and the caller should + * restart loading at the position in {@code positionHolder}. Otherwise, the atom is read/skipped. + */ + private boolean readAtomPayload(ExtractorInput input, PositionHolder positionHolder) + throws IOException, InterruptedException { + long atomPayloadSize = atomSize - atomHeaderBytesRead; + long atomEndPosition = input.getPosition() + atomPayloadSize; + boolean seekRequired = false; + if (atomData != null) { + input.readFully(atomData.data, atomHeaderBytesRead, (int) atomPayloadSize); + if (atomType == Atom.TYPE_ftyp) { + isQuickTime = processFtypAtom(atomData); + } else if (!containerAtoms.isEmpty()) { + containerAtoms.peek().add(new Atom.LeafAtom(atomType, atomData)); + } + } else { + // We don't need the data. Skip or seek, depending on how large the atom is. + if (atomPayloadSize < RELOAD_MINIMUM_SEEK_DISTANCE) { + input.skipFully((int) atomPayloadSize); + } else { + positionHolder.position = input.getPosition() + atomPayloadSize; + seekRequired = true; + } + } + processAtomEnded(atomEndPosition); + return seekRequired && parserState != STATE_READING_SAMPLE; + } + + private void processAtomEnded(long atomEndPosition) throws ParserException { + while (!containerAtoms.isEmpty() && containerAtoms.peek().endPosition == atomEndPosition) { + Atom.ContainerAtom containerAtom = containerAtoms.pop(); + if (containerAtom.type == Atom.TYPE_moov) { + // We've reached the end of the moov atom. Process it and prepare to read samples. + processMoovAtom(containerAtom); + containerAtoms.clear(); + parserState = STATE_READING_SAMPLE; + } else if (!containerAtoms.isEmpty()) { + containerAtoms.peek().add(containerAtom); + } + } + if (parserState != STATE_READING_SAMPLE) { + enterReadingAtomHeaderState(); + } + } + + /** + * Updates the stored track metadata to reflect the contents of the specified moov atom. + */ + private void processMoovAtom(ContainerAtom moov) throws ParserException { + int firstVideoTrackIndex = C.INDEX_UNSET; + long durationUs = C.TIME_UNSET; + List<Mp4Track> tracks = new ArrayList<>(); + + // Process metadata. + Metadata udtaMetadata = null; + GaplessInfoHolder gaplessInfoHolder = new GaplessInfoHolder(); + Atom.LeafAtom udta = moov.getLeafAtomOfType(Atom.TYPE_udta); + if (udta != null) { + udtaMetadata = AtomParsers.parseUdta(udta, isQuickTime); + if (udtaMetadata != null) { + gaplessInfoHolder.setFromMetadata(udtaMetadata); + } + } + Metadata mdtaMetadata = null; + Atom.ContainerAtom meta = moov.getContainerAtomOfType(Atom.TYPE_meta); + if (meta != null) { + mdtaMetadata = AtomParsers.parseMdtaFromMeta(meta); + } + + boolean ignoreEditLists = (flags & FLAG_WORKAROUND_IGNORE_EDIT_LISTS) != 0; + ArrayList<TrackSampleTable> trackSampleTables = + getTrackSampleTables(moov, gaplessInfoHolder, ignoreEditLists); + + int trackCount = trackSampleTables.size(); + for (int i = 0; i < trackCount; i++) { + TrackSampleTable trackSampleTable = trackSampleTables.get(i); + Track track = trackSampleTable.track; + long trackDurationUs = + track.durationUs != C.TIME_UNSET ? track.durationUs : trackSampleTable.durationUs; + durationUs = Math.max(durationUs, trackDurationUs); + Mp4Track mp4Track = new Mp4Track(track, trackSampleTable, + extractorOutput.track(i, track.type)); + + // Each sample has up to three bytes of overhead for the start code that replaces its length. + // Allow ten source samples per output sample, like the platform extractor. + int maxInputSize = trackSampleTable.maximumSize + 3 * 10; + Format format = track.format.copyWithMaxInputSize(maxInputSize); + if (track.type == C.TRACK_TYPE_VIDEO + && trackDurationUs > 0 + && trackSampleTable.sampleCount > 1) { + float frameRate = trackSampleTable.sampleCount / (trackDurationUs / 1000000f); + format = format.copyWithFrameRate(frameRate); + } + format = + MetadataUtil.getFormatWithMetadata( + track.type, format, udtaMetadata, mdtaMetadata, gaplessInfoHolder); + mp4Track.trackOutput.format(format); + + if (track.type == C.TRACK_TYPE_VIDEO && firstVideoTrackIndex == C.INDEX_UNSET) { + firstVideoTrackIndex = tracks.size(); + } + tracks.add(mp4Track); + } + this.firstVideoTrackIndex = firstVideoTrackIndex; + this.durationUs = durationUs; + this.tracks = tracks.toArray(new Mp4Track[0]); + accumulatedSampleSizes = calculateAccumulatedSampleSizes(this.tracks); + + extractorOutput.endTracks(); + extractorOutput.seekMap(this); + } + + private ArrayList<TrackSampleTable> getTrackSampleTables( + ContainerAtom moov, GaplessInfoHolder gaplessInfoHolder, boolean ignoreEditLists) + throws ParserException { + ArrayList<TrackSampleTable> trackSampleTables = new ArrayList<>(); + for (int i = 0; i < moov.containerChildren.size(); i++) { + Atom.ContainerAtom atom = moov.containerChildren.get(i); + if (atom.type != Atom.TYPE_trak) { + continue; + } + Track track = + AtomParsers.parseTrak( + atom, + moov.getLeafAtomOfType(Atom.TYPE_mvhd), + /* duration= */ C.TIME_UNSET, + /* drmInitData= */ null, + ignoreEditLists, + isQuickTime); + if (track == null) { + continue; + } + Atom.ContainerAtom stblAtom = + atom.getContainerAtomOfType(Atom.TYPE_mdia) + .getContainerAtomOfType(Atom.TYPE_minf) + .getContainerAtomOfType(Atom.TYPE_stbl); + TrackSampleTable trackSampleTable = AtomParsers.parseStbl(track, stblAtom, gaplessInfoHolder); + if (trackSampleTable.sampleCount == 0) { + continue; + } + trackSampleTables.add(trackSampleTable); + } + return trackSampleTables; + } + + /** + * Attempts to extract the next sample in the current mdat atom for the specified track. + * <p> + * Returns {@link #RESULT_SEEK} if the source should be reloaded from the position in + * {@code positionHolder}. + * <p> + * Returns {@link #RESULT_END_OF_INPUT} if no samples are left. Otherwise, returns + * {@link #RESULT_CONTINUE}. + * + * @param input The {@link ExtractorInput} from which to read data. + * @param positionHolder If {@link #RESULT_SEEK} is returned, this holder is updated to hold the + * position of the required data. + * @return One of the {@code RESULT_*} flags in {@link Extractor}. + * @throws IOException If an error occurs reading from the input. + * @throws InterruptedException If the thread is interrupted. + */ + private int readSample(ExtractorInput input, PositionHolder positionHolder) + throws IOException, InterruptedException { + long inputPosition = input.getPosition(); + if (sampleTrackIndex == C.INDEX_UNSET) { + sampleTrackIndex = getTrackIndexOfNextReadSample(inputPosition); + if (sampleTrackIndex == C.INDEX_UNSET) { + return RESULT_END_OF_INPUT; + } + } + Mp4Track track = tracks[sampleTrackIndex]; + TrackOutput trackOutput = track.trackOutput; + int sampleIndex = track.sampleIndex; + long position = track.sampleTable.offsets[sampleIndex]; + int sampleSize = track.sampleTable.sizes[sampleIndex]; + long skipAmount = position - inputPosition + sampleBytesRead; + if (skipAmount < 0 || skipAmount >= RELOAD_MINIMUM_SEEK_DISTANCE) { + positionHolder.position = position; + return RESULT_SEEK; + } + if (track.track.sampleTransformation == Track.TRANSFORMATION_CEA608_CDAT) { + // The sample information is contained in a cdat atom. The header must be discarded for + // committing. + skipAmount += Atom.HEADER_SIZE; + sampleSize -= Atom.HEADER_SIZE; + } + input.skipFully((int) skipAmount); + if (track.track.nalUnitLengthFieldLength != 0) { + // Zero the top three bytes of the array that we'll use to decode nal unit lengths, in case + // they're only 1 or 2 bytes long. + byte[] nalLengthData = nalLength.data; + nalLengthData[0] = 0; + nalLengthData[1] = 0; + nalLengthData[2] = 0; + int nalUnitLengthFieldLength = track.track.nalUnitLengthFieldLength; + int nalUnitLengthFieldLengthDiff = 4 - track.track.nalUnitLengthFieldLength; + // NAL units are length delimited, but the decoder requires start code delimited units. + // Loop until we've written the sample to the track output, replacing length delimiters with + // start codes as we encounter them. + while (sampleBytesWritten < sampleSize) { + if (sampleCurrentNalBytesRemaining == 0) { + // Read the NAL length so that we know where we find the next one. + input.readFully(nalLengthData, nalUnitLengthFieldLengthDiff, nalUnitLengthFieldLength); + sampleBytesRead += nalUnitLengthFieldLength; + nalLength.setPosition(0); + int nalLengthInt = nalLength.readInt(); + if (nalLengthInt < 0) { + throw new ParserException("Invalid NAL length"); + } + sampleCurrentNalBytesRemaining = nalLengthInt; + // Write a start code for the current NAL unit. + nalStartCode.setPosition(0); + trackOutput.sampleData(nalStartCode, 4); + sampleBytesWritten += 4; + sampleSize += nalUnitLengthFieldLengthDiff; + } else { + // Write the payload of the NAL unit. + int writtenBytes = trackOutput.sampleData(input, sampleCurrentNalBytesRemaining, false); + sampleBytesRead += writtenBytes; + sampleBytesWritten += writtenBytes; + sampleCurrentNalBytesRemaining -= writtenBytes; + } + } + } else { + if (MimeTypes.AUDIO_AC4.equals(track.track.format.sampleMimeType)) { + if (sampleBytesWritten == 0) { + Ac4Util.getAc4SampleHeader(sampleSize, scratch); + trackOutput.sampleData(scratch, Ac4Util.SAMPLE_HEADER_SIZE); + sampleBytesWritten += Ac4Util.SAMPLE_HEADER_SIZE; + } + sampleSize += Ac4Util.SAMPLE_HEADER_SIZE; + } + while (sampleBytesWritten < sampleSize) { + int writtenBytes = trackOutput.sampleData(input, sampleSize - sampleBytesWritten, false); + sampleBytesRead += writtenBytes; + sampleBytesWritten += writtenBytes; + sampleCurrentNalBytesRemaining -= writtenBytes; + } + } + trackOutput.sampleMetadata(track.sampleTable.timestampsUs[sampleIndex], + track.sampleTable.flags[sampleIndex], sampleSize, 0, null); + track.sampleIndex++; + sampleTrackIndex = C.INDEX_UNSET; + sampleBytesRead = 0; + sampleBytesWritten = 0; + sampleCurrentNalBytesRemaining = 0; + return RESULT_CONTINUE; + } + + /** + * Returns the index of the track that contains the next sample to be read, or {@link + * C#INDEX_UNSET} if no samples remain. + * + * <p>The preferred choice is the sample with the smallest offset not requiring a source reload, + * or if not available the sample with the smallest overall offset to avoid subsequent source + * reloads. + * + * <p>To deal with poor sample interleaving, we also check whether the required memory to catch up + * with the next logical sample (based on sample time) exceeds {@link + * #MAXIMUM_READ_AHEAD_BYTES_STREAM}. If this is the case, we continue with this sample even + * though it may require a source reload. + */ + private int getTrackIndexOfNextReadSample(long inputPosition) { + long preferredSkipAmount = Long.MAX_VALUE; + boolean preferredRequiresReload = true; + int preferredTrackIndex = C.INDEX_UNSET; + long preferredAccumulatedBytes = Long.MAX_VALUE; + long minAccumulatedBytes = Long.MAX_VALUE; + boolean minAccumulatedBytesRequiresReload = true; + int minAccumulatedBytesTrackIndex = C.INDEX_UNSET; + for (int trackIndex = 0; trackIndex < tracks.length; trackIndex++) { + Mp4Track track = tracks[trackIndex]; + int sampleIndex = track.sampleIndex; + if (sampleIndex == track.sampleTable.sampleCount) { + continue; + } + long sampleOffset = track.sampleTable.offsets[sampleIndex]; + long sampleAccumulatedBytes = accumulatedSampleSizes[trackIndex][sampleIndex]; + long skipAmount = sampleOffset - inputPosition; + boolean requiresReload = skipAmount < 0 || skipAmount >= RELOAD_MINIMUM_SEEK_DISTANCE; + if ((!requiresReload && preferredRequiresReload) + || (requiresReload == preferredRequiresReload && skipAmount < preferredSkipAmount)) { + preferredRequiresReload = requiresReload; + preferredSkipAmount = skipAmount; + preferredTrackIndex = trackIndex; + preferredAccumulatedBytes = sampleAccumulatedBytes; + } + if (sampleAccumulatedBytes < minAccumulatedBytes) { + minAccumulatedBytes = sampleAccumulatedBytes; + minAccumulatedBytesRequiresReload = requiresReload; + minAccumulatedBytesTrackIndex = trackIndex; + } + } + return minAccumulatedBytes == Long.MAX_VALUE + || !minAccumulatedBytesRequiresReload + || preferredAccumulatedBytes < minAccumulatedBytes + MAXIMUM_READ_AHEAD_BYTES_STREAM + ? preferredTrackIndex + : minAccumulatedBytesTrackIndex; + } + + /** + * Updates every track's sample index to point its latest sync sample before/at {@code timeUs}. + */ + private void updateSampleIndices(long timeUs) { + for (Mp4Track track : tracks) { + TrackSampleTable sampleTable = track.sampleTable; + int sampleIndex = sampleTable.getIndexOfEarlierOrEqualSynchronizationSample(timeUs); + if (sampleIndex == C.INDEX_UNSET) { + // Handle the case where the requested time is before the first synchronization sample. + sampleIndex = sampleTable.getIndexOfLaterOrEqualSynchronizationSample(timeUs); + } + track.sampleIndex = sampleIndex; + } + } + + /** + * Possibly skips the version and flags fields (1+3 byte) of a full meta atom of the {@code + * input}. + * + * <p>Atoms of type {@link Atom#TYPE_meta} are defined to be full atoms which have four additional + * bytes for a version and a flags field (see 4.2 'Object Structure' in ISO/IEC 14496-12:2005). + * QuickTime do not have such a full box structure. Since some of these files are encoded wrongly, + * we can't rely on the file type though. Instead we must check the 8 bytes after the common + * header bytes ourselves. + */ + private void maybeSkipRemainingMetaAtomHeaderBytes(ExtractorInput input) + throws IOException, InterruptedException { + scratch.reset(8); + // Peek the next 8 bytes which can be either + // (iso) [1 byte version + 3 bytes flags][4 byte size of next atom] + // (qt) [4 byte size of next atom ][4 byte hdlr atom type ] + // In case of (iso) we need to skip the next 4 bytes. + input.peekFully(scratch.data, 0, 8); + scratch.skipBytes(4); + if (scratch.readInt() == Atom.TYPE_hdlr) { + input.resetPeekPosition(); + } else { + input.skipFully(4); + } + } + + /** + * For each sample of each track, calculates accumulated size of all samples which need to be read + * before this sample can be used. + */ + private static long[][] calculateAccumulatedSampleSizes(Mp4Track[] tracks) { + long[][] accumulatedSampleSizes = new long[tracks.length][]; + int[] nextSampleIndex = new int[tracks.length]; + long[] nextSampleTimesUs = new long[tracks.length]; + boolean[] tracksFinished = new boolean[tracks.length]; + for (int i = 0; i < tracks.length; i++) { + accumulatedSampleSizes[i] = new long[tracks[i].sampleTable.sampleCount]; + nextSampleTimesUs[i] = tracks[i].sampleTable.timestampsUs[0]; + } + long accumulatedSampleSize = 0; + int finishedTracks = 0; + while (finishedTracks < tracks.length) { + long minTimeUs = Long.MAX_VALUE; + int minTimeTrackIndex = -1; + for (int i = 0; i < tracks.length; i++) { + if (!tracksFinished[i] && nextSampleTimesUs[i] <= minTimeUs) { + minTimeTrackIndex = i; + minTimeUs = nextSampleTimesUs[i]; + } + } + int trackSampleIndex = nextSampleIndex[minTimeTrackIndex]; + accumulatedSampleSizes[minTimeTrackIndex][trackSampleIndex] = accumulatedSampleSize; + accumulatedSampleSize += tracks[minTimeTrackIndex].sampleTable.sizes[trackSampleIndex]; + nextSampleIndex[minTimeTrackIndex] = ++trackSampleIndex; + if (trackSampleIndex < accumulatedSampleSizes[minTimeTrackIndex].length) { + nextSampleTimesUs[minTimeTrackIndex] = + tracks[minTimeTrackIndex].sampleTable.timestampsUs[trackSampleIndex]; + } else { + tracksFinished[minTimeTrackIndex] = true; + finishedTracks++; + } + } + return accumulatedSampleSizes; + } + + /** + * Adjusts a seek point offset to take into account the track with the given {@code sampleTable}, + * for a given {@code seekTimeUs}. + * + * @param sampleTable The sample table to use. + * @param seekTimeUs The seek time in microseconds. + * @param offset The current offset. + * @return The adjusted offset. + */ + private static long maybeAdjustSeekOffset( + TrackSampleTable sampleTable, long seekTimeUs, long offset) { + int sampleIndex = getSynchronizationSampleIndex(sampleTable, seekTimeUs); + if (sampleIndex == C.INDEX_UNSET) { + return offset; + } + long sampleOffset = sampleTable.offsets[sampleIndex]; + return Math.min(sampleOffset, offset); + } + + /** + * Returns the index of the synchronization sample before or at {@code timeUs}, or the index of + * the first synchronization sample if located after {@code timeUs}, or {@link C#INDEX_UNSET} if + * there are no synchronization samples in the table. + * + * @param sampleTable The sample table in which to locate a synchronization sample. + * @param timeUs A time in microseconds. + * @return The index of the synchronization sample before or at {@code timeUs}, or the index of + * the first synchronization sample if located after {@code timeUs}, or {@link C#INDEX_UNSET} + * if there are no synchronization samples in the table. + */ + private static int getSynchronizationSampleIndex(TrackSampleTable sampleTable, long timeUs) { + int sampleIndex = sampleTable.getIndexOfEarlierOrEqualSynchronizationSample(timeUs); + if (sampleIndex == C.INDEX_UNSET) { + // Handle the case where the requested time is before the first synchronization sample. + sampleIndex = sampleTable.getIndexOfLaterOrEqualSynchronizationSample(timeUs); + } + return sampleIndex; + } + + /** + * Process an ftyp atom to determine whether the media is QuickTime. + * + * @param atomData The ftyp atom data. + * @return Whether the media is QuickTime. + */ + private static boolean processFtypAtom(ParsableByteArray atomData) { + atomData.setPosition(Atom.HEADER_SIZE); + int majorBrand = atomData.readInt(); + if (majorBrand == BRAND_QUICKTIME) { + return true; + } + atomData.skipBytes(4); // minor_version + while (atomData.bytesLeft() > 0) { + if (atomData.readInt() == BRAND_QUICKTIME) { + return true; + } + } + return false; + } + + /** Returns whether the extractor should decode a leaf atom with type {@code atom}. */ + private static boolean shouldParseLeafAtom(int atom) { + return atom == Atom.TYPE_mdhd + || atom == Atom.TYPE_mvhd + || atom == Atom.TYPE_hdlr + || atom == Atom.TYPE_stsd + || atom == Atom.TYPE_stts + || atom == Atom.TYPE_stss + || atom == Atom.TYPE_ctts + || atom == Atom.TYPE_elst + || atom == Atom.TYPE_stsc + || atom == Atom.TYPE_stsz + || atom == Atom.TYPE_stz2 + || atom == Atom.TYPE_stco + || atom == Atom.TYPE_co64 + || atom == Atom.TYPE_tkhd + || atom == Atom.TYPE_ftyp + || atom == Atom.TYPE_udta + || atom == Atom.TYPE_keys + || atom == Atom.TYPE_ilst; + } + + /** Returns whether the extractor should decode a container atom with type {@code atom}. */ + private static boolean shouldParseContainerAtom(int atom) { + return atom == Atom.TYPE_moov + || atom == Atom.TYPE_trak + || atom == Atom.TYPE_mdia + || atom == Atom.TYPE_minf + || atom == Atom.TYPE_stbl + || atom == Atom.TYPE_edts + || atom == Atom.TYPE_meta; + } + + private static final class Mp4Track { + + public final Track track; + public final TrackSampleTable sampleTable; + public final TrackOutput trackOutput; + + public int sampleIndex; + + public Mp4Track(Track track, TrackSampleTable sampleTable, TrackOutput trackOutput) { + this.track = track; + this.sampleTable = sampleTable; + this.trackOutput = trackOutput; + } + + } + +} |