Added MPEG2-Program Stream extractor.
------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=117219856
This commit is contained in:
olly
Oliver Woodman
parent
2b4dcbef3f
commit
ba88091c7b
@ -161,6 +161,13 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
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} catch (ClassNotFoundException e) {
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} catch (ClassNotFoundException e) {
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// Extractor not found.
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// Extractor not found.
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}
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}
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try {
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DEFAULT_EXTRACTOR_CLASSES.add(
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Class.forName("com.google.android.exoplayer.extractor.ts.PsExtractor")
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.asSubclass(Extractor.class));
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} catch (ClassNotFoundException e) {
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// Extractor not found.
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}
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}
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}
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private final ExtractorHolder extractorHolder;
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private final ExtractorHolder extractorHolder;
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@ -0,0 +1,327 @@
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/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.android.exoplayer.extractor.ts;
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import com.google.android.exoplayer.C;
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import com.google.android.exoplayer.extractor.Extractor;
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import com.google.android.exoplayer.extractor.ExtractorInput;
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import com.google.android.exoplayer.extractor.ExtractorOutput;
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import com.google.android.exoplayer.extractor.PositionHolder;
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import com.google.android.exoplayer.extractor.SeekMap;
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import com.google.android.exoplayer.util.ParsableBitArray;
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import com.google.android.exoplayer.util.ParsableByteArray;
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import android.util.Log;
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import android.util.SparseArray;
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import java.io.IOException;
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/**
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* Facilitates the extraction of data from the MPEG-2 TS container format.
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*/
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public final class PsExtractor implements Extractor {
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private static final String TAG = "PsExtractor";
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private static final int PACK_START_CODE = 0x000001BA;
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private static final int SYSTEM_HEADER_START_CODE = 0x000001BB;
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private static final int PACKET_START_CODE_PREFIX = 0x000001;
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private static final int MPEG_PROGRAM_END_CODE = 0x000001B9;
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private static final long MAX_SEARCH_LENGTH = 1024 * 1024;
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public static final int PRIVATE_STREAM_1 = 0xBD;
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public static final int AUDIO_STREAM = 0xC0;
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public static final int AUDIO_STREAM_MASK = 0xE0;
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public static final int VIDEO_STREAM = 0xE0;
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public static final int VIDEO_STREAM_MASK = 0xF0;
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private final PtsTimestampAdjuster ptsTimestampAdjuster;
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private final SparseArray<PesReader> psPayloadReaders; // Indexed by pid
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private final ParsableByteArray psPacketBuffer;
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private boolean foundAllTracks;
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private boolean foundAudioTrack;
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private boolean foundVideoTrack;
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// Accessed only by the loading thread.
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private ExtractorOutput output;
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public PsExtractor() {
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this(new PtsTimestampAdjuster(0));
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}
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public PsExtractor(PtsTimestampAdjuster ptsTimestampAdjuster) {
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this.ptsTimestampAdjuster = ptsTimestampAdjuster;
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psPacketBuffer = new ParsableByteArray(4096);
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psPayloadReaders = new SparseArray<>();
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}
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// Extractor implementation.
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@Override
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public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
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byte[] scratch = new byte[14];
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input.peekFully(scratch, 0, 14);
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// Verify the PACK_START_CODE for the first 4 bytes
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if (PACK_START_CODE != (((scratch[0] & 0xFF) << 24) | ((scratch[1] & 0xFF) << 16)
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| ((scratch[2] & 0xFF) << 8) | (scratch[3] & 0xFF))) {
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return false;
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}
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// Verify the 01xxx1xx marker on the 5th byte
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if ((scratch[4] & 0xC4) != 0x44) {
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return false;
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}
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// Verify the xxxxx1xx marker on the 7th byte
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if ((scratch[6] & 0x04) != 0x04) {
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return false;
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}
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// Verify the xxxxx1xx marker on the 9th byte
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if ((scratch[8] & 0x04) != 0x04) {
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return false;
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}
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// Verify the xxxxxxx1 marker on the 10th byte
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if ((scratch[9] & 0x01) != 0x01) {
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return false;
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}
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// Verify the xxxxxx11 marker on the 13th byte
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if ((scratch[12] & 0x03) != 0x03) {
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return false;
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}
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// Read the stuffing length from the 14th byte (last 3 bits)
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int packStuffingLength = scratch[13] & 0x07;
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input.advancePeekPosition(packStuffingLength);
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// Now check that the next 3 bytes are the beginning of an MPEG start code
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input.peekFully(scratch, 0, 3);
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return (PACKET_START_CODE_PREFIX == (((scratch[0] & 0xFF) << 16) | ((scratch[1] & 0xFF) << 8)
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| (scratch[2] & 0xFF)));
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}
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@Override
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public void init(ExtractorOutput output) {
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this.output = output;
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output.seekMap(new SeekMap.Unseekable(C.UNKNOWN_TIME_US));
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}
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@Override
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public void seek() {
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ptsTimestampAdjuster.reset();
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for (int i = 0; i < psPayloadReaders.size(); i++) {
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psPayloadReaders.valueAt(i).seek();
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}
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}
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@Override
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public int read(ExtractorInput input, PositionHolder seekPosition)
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throws IOException, InterruptedException {
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// First peek and check what type of start code is next.
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if (!input.peekFully(psPacketBuffer.data, 0, 4, true)) {
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return RESULT_END_OF_INPUT;
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}
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psPacketBuffer.setPosition(0);
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int nextStartCode = psPacketBuffer.readInt();
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if (nextStartCode == MPEG_PROGRAM_END_CODE) {
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return RESULT_END_OF_INPUT;
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} else if (nextStartCode == PACK_START_CODE) {
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// Now peek the rest of the pack_header.
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input.peekFully(psPacketBuffer.data, 0, 10);
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// We only care about the pack_stuffing_length in here, skip the first 77 bits.
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psPacketBuffer.setPosition(0);
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psPacketBuffer.skipBytes(9);
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// Last 3 bits is the length.
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int packStuffingLength = psPacketBuffer.readUnsignedByte() & 0x07;
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// Now skip the stuffing and the pack header.
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input.skipFully(packStuffingLength + 14);
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return RESULT_CONTINUE;
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} else if (nextStartCode == SYSTEM_HEADER_START_CODE) {
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// We just skip all this, but we need to get the length first.
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input.peekFully(psPacketBuffer.data, 0, 2);
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// Length is the next 2 bytes.
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psPacketBuffer.setPosition(0);
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int systemHeaderLength = psPacketBuffer.readUnsignedShort();
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input.skipFully(systemHeaderLength + 6);
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return RESULT_CONTINUE;
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} else if (((nextStartCode & 0xFFFFFF00) >> 8) != PACKET_START_CODE_PREFIX) {
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Log.w(TAG, "Missing PACKET_START_CODE_PREFIX!!");
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input.skipFully(1); // Skip bytes until we see a valid start code again.
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return RESULT_CONTINUE;
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}
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// We're at the start of a regular PES packet now.
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// Get the stream ID off the last byte of the start code.
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int streamId = nextStartCode & 0xFF;
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// Check to see if we have this one in our map yet, and if not, then add it.
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PesReader payloadReader = psPayloadReaders.get(streamId);
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if (!foundAllTracks) {
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if (payloadReader == null) {
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if (streamId == PRIVATE_STREAM_1 && !foundAudioTrack) {
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// Private stream, used for AC3 audio.
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// NOTE: This may need further parsing to determine if its DTS,
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// but that's likely only valid for DVDs.
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payloadReader = new PesReader(new Ac3Reader(output.track(streamId), false));
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psPayloadReaders.put(streamId, payloadReader);
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foundAudioTrack = true;
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Log.d(TAG, "Setup payload reader for AC3");
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} else if ((streamId & AUDIO_STREAM_MASK) == AUDIO_STREAM && !foundAudioTrack) {
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payloadReader = new PesReader(new MpegAudioReader(output.track(streamId)));
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psPayloadReaders.put(streamId, payloadReader);
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foundAudioTrack = true;
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Log.d(TAG, "Setup payload reader for MP2");
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} else if ((streamId & VIDEO_STREAM_MASK) == VIDEO_STREAM && !foundVideoTrack) {
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payloadReader = new PesReader(new H262Reader(output.track(streamId)));
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psPayloadReaders.put(streamId, payloadReader);
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foundVideoTrack = true;
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Log.d(TAG, "Setup payload reader for MPEG2Video");
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}
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}
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if ((foundAudioTrack && foundVideoTrack) || input.getPosition() > MAX_SEARCH_LENGTH) {
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foundAllTracks = true;
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output.endTracks();
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Log.d(TAG, "Signalled that all tracks were found");
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}
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}
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// The next 2 bytes are the length, once we have that we can consume the complete packet.
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input.peekFully(psPacketBuffer.data, 0, 2);
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psPacketBuffer.setPosition(0);
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int payloadLength = psPacketBuffer.readUnsignedShort();
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int pesLength = payloadLength + 6;
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if (payloadReader == null) {
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// Just skip this data.
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input.skipFully(pesLength);
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} else {
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if (psPacketBuffer.capacity() < pesLength) {
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// Reallocate for this and future packets.
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psPacketBuffer.reset(new byte[pesLength], pesLength);
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}
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// Read the whole packet and the header for consumption.
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input.readFully(psPacketBuffer.data, 0, pesLength);
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psPacketBuffer.setPosition(6);
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psPacketBuffer.setLimit(pesLength);
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payloadReader.consume(psPacketBuffer, output);
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psPacketBuffer.setLimit(psPacketBuffer.capacity());
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}
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return RESULT_CONTINUE;
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}
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// Internals.
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/**
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* Parses PES packet data and extracts samples.
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*/
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private class PesReader {
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private static final int PES_SCRATCH_SIZE = 64;
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private final ParsableBitArray pesScratch;
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private final ElementaryStreamReader pesPayloadReader;
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private boolean ptsFlag;
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private boolean dtsFlag;
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private boolean seenFirstDts;
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private int extendedHeaderLength;
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private long timeUs;
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public PesReader(ElementaryStreamReader pesPayloadReader) {
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this.pesPayloadReader = pesPayloadReader;
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pesScratch = new ParsableBitArray(new byte[PES_SCRATCH_SIZE]);
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}
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/**
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* Notifies the reader that a seek has occurred.
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* <p>
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* Following a call to this method, the data passed to the next invocation of
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* {@link #consume(ParsableByteArray, ExtractorOutput)} will not be a continuation of
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* the data that was previously passed. Hence the reader should reset any internal state.
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*/
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public void seek() {
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seenFirstDts = false;
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pesPayloadReader.seek();
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}
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/**
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* Consumes the payload of a PS packet.
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*
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* @param data The PES packet. The position will be set to the start of the payload.
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* @param output The output to which parsed data should be written.
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*/
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public void consume(ParsableByteArray data, ExtractorOutput output) {
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data.readBytes(pesScratch.data, 0, 3);
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pesScratch.setPosition(0);
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parseHeader();
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data.readBytes(pesScratch.data, 0, extendedHeaderLength);
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pesScratch.setPosition(0);
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parseHeaderExtension();
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pesPayloadReader.packetStarted(timeUs, true);
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pesPayloadReader.consume(data);
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// We always have complete PES packets with program stream.
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pesPayloadReader.packetFinished();
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}
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private void parseHeader() {
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// Note: see ISO/IEC 13818-1, section 2.4.3.6 for detailed information on the format of
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// the header.
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// First 8 bits are skipped: '10' (2), PES_scrambling_control (2), PES_priority (1),
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// data_alignment_indicator (1), copyright (1), original_or_copy (1)
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pesScratch.skipBits(8);
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ptsFlag = pesScratch.readBit();
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dtsFlag = pesScratch.readBit();
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// ESCR_flag (1), ES_rate_flag (1), DSM_trick_mode_flag (1),
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// additional_copy_info_flag (1), PES_CRC_flag (1), PES_extension_flag (1)
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pesScratch.skipBits(6);
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extendedHeaderLength = pesScratch.readBits(8);
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}
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private void parseHeaderExtension() {
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timeUs = 0;
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if (ptsFlag) {
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pesScratch.skipBits(4); // '0010' or '0011'
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long pts = (long) pesScratch.readBits(3) << 30;
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pesScratch.skipBits(1); // marker_bit
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pts |= pesScratch.readBits(15) << 15;
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pesScratch.skipBits(1); // marker_bit
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pts |= pesScratch.readBits(15);
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pesScratch.skipBits(1); // marker_bit
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if (!seenFirstDts && dtsFlag) {
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pesScratch.skipBits(4); // '0011'
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long dts = (long) pesScratch.readBits(3) << 30;
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pesScratch.skipBits(1); // marker_bit
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dts |= pesScratch.readBits(15) << 15;
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pesScratch.skipBits(1); // marker_bit
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dts |= pesScratch.readBits(15);
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pesScratch.skipBits(1); // marker_bit
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// Subsequent PES packets may have earlier presentation timestamps than this one, but they
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// should all be greater than or equal to this packet's decode timestamp. We feed the
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// decode timestamp to the adjuster here so that in the case that this is the first to be
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// fed, the adjuster will be able to compute an offset to apply such that the adjusted
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// presentation timestamps of all future packets are non-negative.
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ptsTimestampAdjuster.adjustTimestamp(dts);
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seenFirstDts = true;
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}
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timeUs = ptsTimestampAdjuster.adjustTimestamp(pts);
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}
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}
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}
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}
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