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added seeking capability for mpeg-ts #1274

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added seeking capability for mpeg-ts #1274

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98 changes: 81 additions & 17 deletions library/src/main/java/com/google/android/exoplayer/extractor/ts/TsExtractor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -30,11 +30,13 @@
import android.util.SparseBooleanArray;

import java.io.IOException;
import java.util.Vector;

/**
* Facilitates the extraction of data from the MPEG-2 TS container format.
* This is copied from exoplayer library but I worked on adding seeking capability
*/
public final class TsExtractor implements Extractor {
public final class TsExtractor implements Extractor,SeekMap {

private static final String TAG = "TsExtractor";

Expand Down Expand Up @@ -70,6 +72,9 @@ public final class TsExtractor implements Extractor {
private ExtractorOutput output;
/* package */ Id3Reader id3Reader;

//pcr array for seeking
private Vector<TimeBytePosition> timeToByte;

public TsExtractor() {
this(new PtsTimestampAdjuster(0));
}
Expand All @@ -86,6 +91,7 @@ public TsExtractor(PtsTimestampAdjuster ptsTimestampAdjuster, boolean idrKeyfram
tsPayloadReaders = new SparseArray<>();
tsPayloadReaders.put(TS_PAT_PID, new PatReader());
streamTypes = new SparseBooleanArray();
timeToByte = new Vector<>();
}

// Extractor implementation.
Expand All @@ -106,20 +112,25 @@ public boolean sniff(ExtractorInput input) throws IOException, InterruptedExcept
@Override
public void init(ExtractorOutput output) {
this.output = output;
output.seekMap(SeekMap.UNSEEKABLE);
output.seekMap(this);
}

@Override
public boolean isSeekable(){
return true;
}

@Override
public void seek() {
ptsTimestampAdjuster.reset();
//ptsTimestampAdjuster.reset(); this reset is not good for seeking
for (int i = 0; i < tsPayloadReaders.size(); i++) {
tsPayloadReaders.valueAt(i).seek();
}
}

@Override
public int read(ExtractorInput input, PositionHolder seekPosition)
throws IOException, InterruptedException {
throws IOException, InterruptedException {
if (!input.readFully(tsPacketBuffer.data, 0, TS_PACKET_SIZE, true)) {
return RESULT_END_OF_INPUT;
}
Expand All @@ -132,7 +143,6 @@ public int read(ExtractorInput input, PositionHolder seekPosition)
if (syncByte != TS_SYNC_BYTE) {
return RESULT_CONTINUE;
}

tsPacketBuffer.readBytes(tsScratch, 3);
tsScratch.skipBits(1); // transport_error_indicator
boolean payloadUnitStartIndicator = tsScratch.readBit();
Expand All @@ -143,10 +153,22 @@ public int read(ExtractorInput input, PositionHolder seekPosition)
boolean payloadExists = tsScratch.readBit();
// Last 4 bits of scratch are skipped: continuity_counter

// Skip the adaptation field.
// check for pcr
if (adaptationFieldExists) {
int adaptationFieldLength = tsPacketBuffer.readUnsignedByte();
tsPacketBuffer.skipBytes(adaptationFieldLength);
if (adaptationFieldLength > 0) {
int flags = tsPacketBuffer.readUnsignedByte();
boolean pcrFlagSet = (flags & 0x10) == 0x10;
if (pcrFlagSet && adaptationFieldLength>=7) {
byte[] pcrBytes=new byte[6];
tsPacketBuffer.readBytes(pcrBytes, 0, pcrBytes.length);
long positionMs=getPcrPositionMs(pcrBytes);
timeToByte.add(new TimeBytePosition(positionMs, input.getPosition() - TS_PACKET_SIZE));
tsPacketBuffer.skipBytes(adaptationFieldLength-7);
} else {
tsPacketBuffer.skipBytes(adaptationFieldLength-1);
}
}
}

// Read the payload.
Expand All @@ -160,6 +182,48 @@ public int read(ExtractorInput input, PositionHolder seekPosition)
return RESULT_CONTINUE;
}

@Override
public long getPosition(long positionUs) {
//search for the closest position using binary search
positionUs/=1000;
//the first time-position might not be aligned with 0(live-streaming)
positionUs+=timeToByte.get(0).timeMs;
int q = 0, r = timeToByte.size();
int mid = -1;
while (q < r) {
mid = (q + r) / 2;
if (timeToByte.get(mid).timeMs == positionUs) {
break;
} else if (timeToByte.get(mid).timeMs > positionUs) {
r = mid;
} else if (timeToByte.get(mid).timeMs < positionUs) {
q = mid + 1;
}
}
return mid == -1 ? 0 : timeToByte.get(mid).bytePos;
}

//gets time position in milliseconds from pcr value
private long getPcrPositionMs(byte[] pcrBytes) {
long pcr=(((long)((pcrBytes[0]<<24)
+(pcrBytes[1]<<16 & 0x00FF0000)
+(pcrBytes[2]<<8 & 0x0000FF00)
+(pcrBytes[3] & 0x000000FF)))<<1 & 0x00000001FFFFFFFFL)
+(pcrBytes[4]>>7 & 1);
return (pcr/90);
}

private class TimeBytePosition{
//position in time
public long timeMs;
//equivalent byte offset
public long bytePos;
public TimeBytePosition(long timeMs,long bytePos){
this.timeMs = timeMs;
this.bytePos = bytePos;
}
}

// Internals.

/**
Expand All @@ -184,7 +248,7 @@ private abstract static class TsPayloadReader {
* @param output The output to which parsed data should be written.
*/
public abstract void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
ExtractorOutput output);
ExtractorOutput output);

}

Expand All @@ -206,7 +270,7 @@ public void seek() {

@Override
public void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
ExtractorOutput output) {
ExtractorOutput output) {
// Skip pointer.
if (payloadUnitStartIndicator) {
int pointerField = data.readUnsignedByte();
Expand Down Expand Up @@ -261,7 +325,7 @@ public void seek() {

@Override
public void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
ExtractorOutput output) {
ExtractorOutput output) {
if (payloadUnitStartIndicator) {
// Skip pointer.
int pointerField = data.readUnsignedByte();
Expand Down Expand Up @@ -309,7 +373,7 @@ public void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
}

int remainingEntriesLength = sectionLength - 9 /* Length of fields before descriptors */
- programInfoLength - 4 /* CRC length */;
- programInfoLength - 4 /* CRC length */;
while (remainingEntriesLength > 0) {
sectionData.readBytes(pmtScratch, 5);
int streamType = pmtScratch.readBits(8);
Expand Down Expand Up @@ -338,7 +402,7 @@ public void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
break;
case TS_STREAM_TYPE_AAC:
pesPayloadReader = new AdtsReader(output.track(TS_STREAM_TYPE_AAC),
new DummyTrackOutput());
new DummyTrackOutput());
break;
case TS_STREAM_TYPE_AC3:
pesPayloadReader = new Ac3Reader(output.track(TS_STREAM_TYPE_AC3), false);
Expand All @@ -355,11 +419,11 @@ public void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
break;
case TS_STREAM_TYPE_H264:
pesPayloadReader = new H264Reader(output.track(TS_STREAM_TYPE_H264),
new SeiReader(output.track(TS_STREAM_TYPE_EIA608)), idrKeyframesOnly);
new SeiReader(output.track(TS_STREAM_TYPE_EIA608)), idrKeyframesOnly);
break;
case TS_STREAM_TYPE_H265:
pesPayloadReader = new H265Reader(output.track(TS_STREAM_TYPE_H265),
new SeiReader(output.track(TS_STREAM_TYPE_EIA608)));
new SeiReader(output.track(TS_STREAM_TYPE_EIA608)));
break;
case TS_STREAM_TYPE_ID3:
pesPayloadReader = id3Reader;
Expand Down Expand Up @@ -463,7 +527,7 @@ public void seek() {

@Override
public void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
ExtractorOutput output) {
ExtractorOutput output) {
if (payloadUnitStartIndicator) {
switch (state) {
case STATE_FINDING_HEADER:
Expand Down Expand Up @@ -502,7 +566,7 @@ public void consume(ParsableByteArray data, boolean payloadUnitStartIndicator,
int readLength = Math.min(MAX_HEADER_EXTENSION_SIZE, extendedHeaderLength);
// Read as much of the extended header as we're interested in, and skip the rest.
if (continueRead(data, pesScratch.data, readLength)
&& continueRead(data, null, extendedHeaderLength)) {
&& continueRead(data, null, extendedHeaderLength)) {
parseHeaderExtension();
pesPayloadReader.packetStarted(timeUs, dataAlignmentIndicator);
setState(STATE_READING_BODY);
Expand Down Expand Up @@ -582,7 +646,7 @@ private boolean parseHeader() {
payloadSize = -1;
} else {
payloadSize = packetLength + 6 /* packetLength does not include the first 6 bytes */
- HEADER_SIZE - extendedHeaderLength;
- HEADER_SIZE - extendedHeaderLength;
}
return true;
}
Expand Down