Parse ID3 sample timestamp for HLS audio chunks
Pending improvement: * Peek just the required priv frame. Avoid decoding all id3 information. * Sniff the used container format instead of using the extension. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=141181781
This commit is contained in:
aquilescanta
Oliver Woodman
parent
e5bc00ea94
commit
a66b4a9bad
@ -278,10 +278,9 @@ import java.util.Locale;
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DataSpec dataSpec = new DataSpec(chunkUri, segment.byterangeOffset, segment.byterangeLength,
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null);
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out.chunk = new HlsMediaChunk(dataSource, dataSpec, initDataSpec, variants[newVariantIndex],
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trackSelection.getSelectionReason(), trackSelection.getSelectionData(),
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startTimeUs, startTimeUs + segment.durationUs, chunkMediaSequence,
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segment.discontinuitySequenceNumber, isTimestampMaster, timestampAdjuster, previous,
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encryptionKey, encryptionIv);
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trackSelection.getSelectionReason(), trackSelection.getSelectionData(), startTimeUs,
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startTimeUs + segment.durationUs, chunkMediaSequence, segment.discontinuitySequenceNumber,
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isTimestampMaster, timestampAdjuster, previous, encryptionKey, encryptionIv);
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}
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/**
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@ -16,6 +16,8 @@
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package com.google.android.exoplayer2.source.hls;
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import android.text.TextUtils;
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import com.google.android.exoplayer2.C;
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import com.google.android.exoplayer2.ParserException;
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import com.google.android.exoplayer2.extractor.DefaultExtractorInput;
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import com.google.android.exoplayer2.extractor.Extractor;
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import com.google.android.exoplayer2.extractor.ExtractorInput;
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@ -26,11 +28,15 @@ import com.google.android.exoplayer2.extractor.ts.Ac3Extractor;
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import com.google.android.exoplayer2.extractor.ts.AdtsExtractor;
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import com.google.android.exoplayer2.extractor.ts.DefaultTsPayloadReaderFactory;
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import com.google.android.exoplayer2.extractor.ts.TsExtractor;
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import com.google.android.exoplayer2.metadata.Metadata;
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import com.google.android.exoplayer2.metadata.id3.Id3Decoder;
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import com.google.android.exoplayer2.metadata.id3.PrivFrame;
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import com.google.android.exoplayer2.source.chunk.MediaChunk;
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import com.google.android.exoplayer2.source.hls.playlist.HlsMasterPlaylist.HlsUrl;
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import com.google.android.exoplayer2.upstream.DataSource;
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import com.google.android.exoplayer2.upstream.DataSpec;
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import com.google.android.exoplayer2.util.MimeTypes;
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import com.google.android.exoplayer2.util.ParsableByteArray;
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import com.google.android.exoplayer2.util.Util;
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import java.io.IOException;
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import java.util.concurrent.atomic.AtomicInteger;
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@ -42,6 +48,9 @@ import java.util.concurrent.atomic.AtomicInteger;
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private static final AtomicInteger UID_SOURCE = new AtomicInteger();
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private static final String PRIV_TIMESTAMP_FRAME_OWNER =
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"com.apple.streaming.transportStreamTimestamp";
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private static final String AAC_FILE_EXTENSION = ".aac";
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private static final String AC3_FILE_EXTENSION = ".ac3";
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private static final String EC3_FILE_EXTENSION = ".ec3";
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@ -71,6 +80,11 @@ import java.util.concurrent.atomic.AtomicInteger;
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private final boolean isMasterTimestampSource;
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private final TimestampAdjuster timestampAdjuster;
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private final HlsMediaChunk previousChunk;
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private final String lastPathSegment;
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private final boolean isPackedAudio;
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private final Id3Decoder id3Decoder;
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private final ParsableByteArray id3Data;
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private Extractor extractor;
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private int initSegmentBytesLoaded;
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@ -113,6 +127,19 @@ import java.util.concurrent.atomic.AtomicInteger;
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this.previousChunk = previousChunk;
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// Note: this.dataSource and dataSource may be different.
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this.isEncrypted = this.dataSource instanceof Aes128DataSource;
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lastPathSegment = dataSpec.uri.getLastPathSegment();
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isPackedAudio = lastPathSegment.endsWith(AAC_FILE_EXTENSION)
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|| lastPathSegment.endsWith(AC3_FILE_EXTENSION)
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|| lastPathSegment.endsWith(EC3_FILE_EXTENSION)
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|| lastPathSegment.endsWith(MP3_FILE_EXTENSION);
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if (isPackedAudio) {
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id3Decoder = previousChunk != null ? previousChunk.id3Decoder : new Id3Decoder();
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id3Data = previousChunk != null ? previousChunk.id3Data
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: new ParsableByteArray(Id3Decoder.ID3_HEADER_LENGTH);
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} else {
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id3Decoder = null;
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id3Data = null;
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}
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initDataSource = dataSource;
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adjustedEndTimeUs = endTimeUs;
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uid = UID_SOURCE.getAndIncrement();
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@ -167,8 +194,9 @@ import java.util.concurrent.atomic.AtomicInteger;
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@Override
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public void load() throws IOException, InterruptedException {
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if (extractor == null) {
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extractor = buildExtractor();
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if (extractor == null && !isPackedAudio) {
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// See HLS spec, version 20, Section 3.4 for more information on packed audio extraction.
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extractor = buildExtractorByExtension();
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}
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maybeLoadInitData();
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if (!loadCanceled) {
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@ -176,27 +204,152 @@ import java.util.concurrent.atomic.AtomicInteger;
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}
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}
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// Private methods.
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// Internal loading methods.
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private Extractor buildExtractor() {
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private void maybeLoadInitData() throws IOException, InterruptedException {
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if ((previousChunk != null && previousChunk.extractor == extractor) || initLoadCompleted
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|| initDataSpec == null) {
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return;
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}
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DataSpec initSegmentDataSpec = Util.getRemainderDataSpec(initDataSpec, initSegmentBytesLoaded);
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try {
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ExtractorInput input = new DefaultExtractorInput(initDataSource,
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initSegmentDataSpec.absoluteStreamPosition, initDataSource.open(initSegmentDataSpec));
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try {
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int result = Extractor.RESULT_CONTINUE;
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while (result == Extractor.RESULT_CONTINUE && !loadCanceled) {
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result = extractor.read(input, null);
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}
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} finally {
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initSegmentBytesLoaded = (int) (input.getPosition() - initDataSpec.absoluteStreamPosition);
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}
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} finally {
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Util.closeQuietly(dataSource);
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}
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initLoadCompleted = true;
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}
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private void loadMedia() throws IOException, InterruptedException {
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// If we previously fed part of this chunk to the extractor, we need to skip it this time. For
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// encrypted content we need to skip the data by reading it through the source, so as to ensure
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// correct decryption of the remainder of the chunk. For clear content, we can request the
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// remainder of the chunk directly.
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DataSpec loadDataSpec;
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boolean skipLoadedBytes;
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if (isEncrypted) {
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loadDataSpec = dataSpec;
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skipLoadedBytes = bytesLoaded != 0;
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} else {
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loadDataSpec = Util.getRemainderDataSpec(dataSpec, bytesLoaded);
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skipLoadedBytes = false;
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}
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if (!isMasterTimestampSource) {
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timestampAdjuster.waitUntilInitialized();
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}
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try {
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ExtractorInput input = new DefaultExtractorInput(dataSource,
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loadDataSpec.absoluteStreamPosition, dataSource.open(loadDataSpec));
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if (extractor == null) {
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// Media segment format is packed audio.
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long id3Timestamp = peekId3PrivTimestamp(input);
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if (id3Timestamp == C.TIME_UNSET) {
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throw new ParserException("ID3 PRIV timestamp missing.");
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}
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extractor = buildPackedAudioExtractor(timestampAdjuster.adjustTsTimestamp(id3Timestamp));
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}
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if (skipLoadedBytes) {
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input.skipFully(bytesLoaded);
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}
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try {
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int result = Extractor.RESULT_CONTINUE;
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while (result == Extractor.RESULT_CONTINUE && !loadCanceled) {
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result = extractor.read(input, null);
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}
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long adjustedEndTimeUs = extractorOutput.getLargestQueuedTimestampUs();
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if (adjustedEndTimeUs != Long.MIN_VALUE) {
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this.adjustedEndTimeUs = adjustedEndTimeUs;
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}
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} finally {
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bytesLoaded = (int) (input.getPosition() - dataSpec.absoluteStreamPosition);
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}
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} finally {
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Util.closeQuietly(dataSource);
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}
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loadCompleted = true;
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}
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/**
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* Peek the presentation timestamp of the first sample in the chunk from an ID3 PRIV as defined
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* in the HLS spec, version 20, Section 3.4. Returns {@link C#TIME_UNSET} if the frame is not
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* found. This method only modifies the peek position.
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*
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* @param input The {@link ExtractorInput} to obtain the PRIV frame from.
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* @return The parsed, adjusted timestamp in microseconds
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* @throws IOException If an error occurred peeking from the input.
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* @throws InterruptedException If the thread was interrupted.
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*/
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private long peekId3PrivTimestamp(ExtractorInput input) throws IOException, InterruptedException {
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input.resetPeekPosition();
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if (!input.peekFully(id3Data.data, 0, Id3Decoder.ID3_HEADER_LENGTH, true)) {
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return C.TIME_UNSET;
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}
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id3Data.reset(Id3Decoder.ID3_HEADER_LENGTH);
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int id = id3Data.readUnsignedInt24();
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if (id != Id3Decoder.ID3_TAG) {
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return C.TIME_UNSET;
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}
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id3Data.skipBytes(3); // version(2), flags(1).
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int id3Size = id3Data.readSynchSafeInt();
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int requiredCapacity = id3Size + Id3Decoder.ID3_HEADER_LENGTH;
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if (requiredCapacity > id3Data.capacity()) {
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byte[] data = id3Data.data;
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id3Data.reset(requiredCapacity);
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System.arraycopy(data, 0, id3Data.data, 0, Id3Decoder.ID3_HEADER_LENGTH);
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}
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if (!input.peekFully(id3Data.data, Id3Decoder.ID3_HEADER_LENGTH, id3Size, true)) {
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return C.TIME_UNSET;
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}
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Metadata metadata = id3Decoder.decode(id3Data.data, id3Size);
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if (metadata == null) {
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return C.TIME_UNSET;
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}
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int metadataLength = metadata.length();
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for (int i = 0; i < metadataLength; i++) {
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Metadata.Entry frame = metadata.get(i);
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if (frame instanceof PrivFrame) {
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PrivFrame privFrame = (PrivFrame) frame;
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if (PRIV_TIMESTAMP_FRAME_OWNER.equals(privFrame.owner)) {
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System.arraycopy(privFrame.privateData, 0, id3Data.data, 0, 8 /* timestamp size */);
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id3Data.reset(8);
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return id3Data.readLong();
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}
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}
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}
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return C.TIME_UNSET;
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}
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// Internal factory methods.
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/**
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* If the content is encrypted, returns an {@link Aes128DataSource} that wraps the original in
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* order to decrypt the loaded data. Else returns the original.
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*/
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private static DataSource buildDataSource(DataSource dataSource, byte[] encryptionKey,
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byte[] encryptionIv) {
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if (encryptionKey == null || encryptionIv == null) {
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return dataSource;
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}
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return new Aes128DataSource(dataSource, encryptionKey, encryptionIv);
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}
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private Extractor buildExtractorByExtension() {
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// Set the extractor that will read the chunk.
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Extractor extractor;
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boolean needNewExtractor = previousChunk == null
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|| previousChunk.discontinuitySequenceNumber != discontinuitySequenceNumber
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|| trackFormat != previousChunk.trackFormat;
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boolean usingNewExtractor = true;
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String lastPathSegment = dataSpec.uri.getLastPathSegment();
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if (lastPathSegment.endsWith(AAC_FILE_EXTENSION)) {
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// TODO: Inject a timestamp adjuster and use it along with ID3 PRIV tag values with owner
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// identifier com.apple.streaming.transportStreamTimestamp. This may also apply to the MP3
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// case below.
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extractor = new AdtsExtractor(startTimeUs);
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} else if (lastPathSegment.endsWith(AC3_FILE_EXTENSION)
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|| lastPathSegment.endsWith(EC3_FILE_EXTENSION)) {
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extractor = new Ac3Extractor(startTimeUs);
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} else if (lastPathSegment.endsWith(MP3_FILE_EXTENSION)) {
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extractor = new Mp3Extractor(startTimeUs);
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} else if (lastPathSegment.endsWith(WEBVTT_FILE_EXTENSION)
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if (lastPathSegment.endsWith(WEBVTT_FILE_EXTENSION)
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|| lastPathSegment.endsWith(VTT_FILE_EXTENSION)) {
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extractor = new WebvttExtractor(trackFormat.language, timestampAdjuster);
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} else if (!needNewExtractor) {
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@ -231,80 +384,20 @@ import java.util.concurrent.atomic.AtomicInteger;
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return extractor;
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}
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private void maybeLoadInitData() throws IOException, InterruptedException {
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if ((previousChunk != null && previousChunk.extractor == extractor)
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|| initLoadCompleted || initDataSpec == null) {
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return;
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}
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DataSpec initSegmentDataSpec = Util.getRemainderDataSpec(initDataSpec, initSegmentBytesLoaded);
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try {
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ExtractorInput input = new DefaultExtractorInput(initDataSource,
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initSegmentDataSpec.absoluteStreamPosition, initDataSource.open(initSegmentDataSpec));
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try {
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int result = Extractor.RESULT_CONTINUE;
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while (result == Extractor.RESULT_CONTINUE && !loadCanceled) {
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result = extractor.read(input, null);
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}
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} finally {
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initSegmentBytesLoaded += (int) (input.getPosition() - dataSpec.absoluteStreamPosition);
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}
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} finally {
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Util.closeQuietly(dataSource);
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}
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initLoadCompleted = true;
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}
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private void loadMedia() throws IOException, InterruptedException {
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// If we previously fed part of this chunk to the extractor, we need to skip it this time. For
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// encrypted content we need to skip the data by reading it through the source, so as to ensure
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// correct decryption of the remainder of the chunk. For clear content, we can request the
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// remainder of the chunk directly.
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DataSpec loadDataSpec;
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boolean skipLoadedBytes;
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if (isEncrypted) {
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loadDataSpec = dataSpec;
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skipLoadedBytes = bytesLoaded != 0;
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private Extractor buildPackedAudioExtractor(long startTimeUs) {
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Extractor extractor;
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if (lastPathSegment.endsWith(AAC_FILE_EXTENSION)) {
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extractor = new AdtsExtractor(startTimeUs);
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} else if (lastPathSegment.endsWith(AC3_FILE_EXTENSION)
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|| lastPathSegment.endsWith(EC3_FILE_EXTENSION)) {
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extractor = new Ac3Extractor(startTimeUs);
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} else if (lastPathSegment.endsWith(MP3_FILE_EXTENSION)) {
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extractor = new Mp3Extractor(startTimeUs);
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} else {
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loadDataSpec = Util.getRemainderDataSpec(dataSpec, bytesLoaded);
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skipLoadedBytes = false;
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throw new IllegalArgumentException("Unkown extension for audio file: " + lastPathSegment);
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}
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try {
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ExtractorInput input = new DefaultExtractorInput(dataSource,
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loadDataSpec.absoluteStreamPosition, dataSource.open(loadDataSpec));
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if (skipLoadedBytes) {
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input.skipFully(bytesLoaded);
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}
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try {
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int result = Extractor.RESULT_CONTINUE;
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if (!isMasterTimestampSource && timestampAdjuster != null) {
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timestampAdjuster.waitUntilInitialized();
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}
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while (result == Extractor.RESULT_CONTINUE && !loadCanceled) {
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result = extractor.read(input, null);
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}
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long adjustedEndTimeUs = extractorOutput.getLargestQueuedTimestampUs();
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if (adjustedEndTimeUs != Long.MIN_VALUE) {
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this.adjustedEndTimeUs = adjustedEndTimeUs;
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}
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} finally {
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bytesLoaded = (int) (input.getPosition() - dataSpec.absoluteStreamPosition);
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}
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} finally {
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Util.closeQuietly(dataSource);
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}
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loadCompleted = true;
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}
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/**
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* If the content is encrypted, returns an {@link Aes128DataSource} that wraps the original in
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* order to decrypt the loaded data. Else returns the original.
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*/
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private static DataSource buildDataSource(DataSource dataSource, byte[] encryptionKey,
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byte[] encryptionIv) {
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if (encryptionKey == null || encryptionIv == null) {
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return dataSource;
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}
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return new Aes128DataSource(dataSource, encryptionKey, encryptionIv);
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extractor.init(extractorOutput);
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return extractor;
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}
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}
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Reference in New Issue
Block a user