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/*
* Copyright (C) 2015 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 com.android.usbtuner;
import android.media.MediaDataSource;
import android.os.Environment;
import android.util.Log;
import android.util.SparseBooleanArray;
import com.android.usbtuner.ChannelScanFileParser.ScanChannel;
import com.android.usbtuner.data.Channel;
import com.android.usbtuner.data.TunerChannel;
import com.android.usbtuner.ts.TsParser;
import com.android.usbtuner.tvinput.EventDetector;
import com.android.usbtuner.tvinput.FileSourceEventDetector;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.List;
/**
* A {@link DataSource} implementation which provides the MPEG-2 TS stream from a local file
* generated by capturing TV signal.
*/
public class FileDataSource extends MediaDataSource implements InputStreamSource {
private static final String TAG = "FileDataSource";
private static final int TS_PACKET_SIZE = 188;
private static final int TS_SYNC_BYTE = 0x47;
private static final int MIN_READ_UNIT = TS_PACKET_SIZE * 10;
private static final int READ_BUFFER_SIZE = MIN_READ_UNIT * 10; // ~20KB
private static final int CIRCULAR_BUFFER_SIZE = MIN_READ_UNIT * 4000; // ~ 8MB
private static final int PADDING_SIZE = MIN_READ_UNIT * 1000; // ~2MB
private static final int READ_TIMEOUT_MS = 10000; // 10 secs.
private static final int BUFFER_UNDERRUN_SLEEP_MS = 10;
private static final String FILE_DIR =
new File(Environment.getExternalStorageDirectory(), "Streams").getAbsolutePath();
// Virtual frequency base used for file-based source
public static final int FREQ_BASE = 100;
private final Object mCircularBufferMonitor = new Object();
private final byte[] mCircularBuffer = new byte[CIRCULAR_BUFFER_SIZE];
private final FileSourceEventDetector mEventDetector;
private long mBytesFetched;
private long mLastReadPosition;
private boolean mStreaming;
private Thread mStreamingThread;
private StreamProvider mSource;
public FileDataSource(EventDetector.EventListener eventListener) {
mEventDetector = new FileSourceEventDetector(eventListener);
}
@Override
public boolean setScanChannel(ScanChannel channel) {
String filepath = new File(FILE_DIR, channel.filename).getAbsolutePath();
mSource = new StreamProvider(filepath);
if (mSource.isReady()) {
mEventDetector.start(mSource);
return true;
}
return false;
}
/**
* Sets the channel required to start streaming from this device. Afterwards, prepares
* the tuner device for streaming. Package retrieval can be made at any time after invoking
* this method and before stopping the stream.
*
* @param channel a {@link TunerChannel} instance tune to
* @return {@code true} if the entire operation was successful; {@code false} otherwise
*/
@Override
public boolean tuneToChannel(TunerChannel channel) {
Log.i(TAG, "tuneToChannel with: " + channel.getFilepath());
mSource = new StreamProvider(channel.getFilepath());
if (!mSource.isReady()) {
return false;
}
mEventDetector.start(mSource);
mSource.addPidFilter(channel.getVideoPid());
mSource.addPidFilter(channel.getAudioPid());
mSource.addPidFilter(channel.getPcrPid());
return true;
}
/**
* Starts streaming data.
*/
@Override
public void startStream() {
mSource.addPidFilter(TsParser.ATSC_SI_BASE_PID);
mSource.addPidFilter(TsParser.PAT_PID);
synchronized (mCircularBufferMonitor) {
if (mStreaming) {
return;
}
mStreaming = true;
}
mStreamingThread = new StreamingThread();
mStreamingThread.start();
Log.i(TAG, "Streaming started");
}
/**
* Blocks the current thread until the streaming thread stops. In rare cases when the tuner
* device is overloaded this can take a while, but usually it returns pretty quickly.
*/
@Override
public void stopStream() {
synchronized (mCircularBufferMonitor) {
mStreaming = false;
mCircularBufferMonitor.notify();
}
try {
if (mStreamingThread != null) {
mStreamingThread.join();
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
@Override
public long getLimit() {
synchronized (mCircularBufferMonitor) {
return mBytesFetched;
}
}
@Override
public long getPosition() {
synchronized (mCircularBufferMonitor) {
return mLastReadPosition;
}
}
/**
* Provides MPEG-2 transport stream from a local file. Stream can be filtered by PID.
*/
public static class StreamProvider {
private final String mFilepath;
private final SparseBooleanArray mPids = new SparseBooleanArray();
private final byte[] mPreBuffer = new byte[READ_BUFFER_SIZE];
private BufferedInputStream mInputStream;
private StreamProvider(String filepath) {
mFilepath = filepath;
open(filepath);
}
private void open(String filepath) {
try {
mInputStream = new BufferedInputStream(new FileInputStream(filepath));
} catch (IOException e) {
Log.e(TAG, "Error opening input stream", e);
mInputStream = null;
}
}
private boolean isReady() {
return mInputStream != null;
}
public String getFilepath() {
return mFilepath;
}
public void addPidFilter(int pid) {
mPids.put(pid, true);
}
public boolean isFilterEmpty() {
return mPids.size() > 0;
}
public void clearPidFilter() {
mPids.clear();
}
public boolean isInFilter(int pid) {
return mPids.get(pid);
}
private int read(byte[] inputBuffer) {
int readSize = readInternal();
if (readSize <= 0) {
// Reached the end of stream. Restart from the beginning.
close();
open(mFilepath);
if (mInputStream == null) {
return -1;
}
readSize = readInternal();
}
if (mPreBuffer[0] != TS_SYNC_BYTE) {
Log.e(TAG, "Error reading input stream - no TS sync found");
return -1;
}
int filteredSize = 0;
for (int i = 0, destPos = 0; i < readSize; i += TS_PACKET_SIZE) {
if (mPreBuffer[i] == TS_SYNC_BYTE) {
int pid = ((mPreBuffer[i + 1] & 0x1f) << 8) + (mPreBuffer[i + 2] & 0xff);
if (mPids.get(pid)) {
System.arraycopy(mPreBuffer, i, inputBuffer, destPos, TS_PACKET_SIZE);
destPos += TS_PACKET_SIZE;
filteredSize += TS_PACKET_SIZE;
}
}
}
return filteredSize;
}
private int readInternal() {
int readSize;
try {
readSize = mInputStream.read(mPreBuffer, 0, mPreBuffer.length);
} catch (IOException e) {
Log.e(TAG, "Error reading input stream", e);
return -1;
}
return readSize;
}
private void close() {
try {
mInputStream.close();
} catch (IOException e) {
Log.e(TAG, "Error closing input stream:", e);
}
mInputStream = null;
}
}
@Override
public int readAt(long pos, byte[] buffer, int offset, int amount) throws IOException {
synchronized (mCircularBufferMonitor) {
long initialBytesFetched = mBytesFetched;
while (mBytesFetched < pos + amount && mStreaming) {
try {
mCircularBufferMonitor.wait(READ_TIMEOUT_MS);
} catch (InterruptedException e) {
// Wait again.
Thread.currentThread().interrupt();
}
if (initialBytesFetched == mBytesFetched) {
Log.w(TAG, "No data update for " + READ_TIMEOUT_MS + "ms. returning -1.");
// Returning -1 will make demux report EOS so that the input service can retry
// the playback.
return -1;
}
}
if (!mStreaming) {
Log.w(TAG, "Stream is already stopped.");
return -1;
}
if (mBytesFetched - CIRCULAR_BUFFER_SIZE > pos) {
Log.e(TAG, "Demux is requesting the data which is already overwritten.");
return -1;
}
int posInBuffer = (int) (pos % CIRCULAR_BUFFER_SIZE);
int bytesToCopyInFirstPass = amount;
if (posInBuffer + bytesToCopyInFirstPass > mCircularBuffer.length) {
bytesToCopyInFirstPass = mCircularBuffer.length - posInBuffer;
}
System.arraycopy(mCircularBuffer, posInBuffer, buffer, offset, bytesToCopyInFirstPass);
if (bytesToCopyInFirstPass < amount) {
System.arraycopy(mCircularBuffer, 0, buffer, offset + bytesToCopyInFirstPass,
amount - bytesToCopyInFirstPass);
}
mLastReadPosition = pos + amount;
mCircularBufferMonitor.notify();
return amount;
}
}
@Override
public long getSize() throws IOException {
return -1;
}
@Override
public void close() {}
@Override
public int getType() {
return Channel.TYPE_FILE;
}
/**
* Adds {@link ScanChannel} instance for local files.
*
* @param output a list of channels where the results will be placed in
*/
public static void addLocalStreamFiles(List<ScanChannel> output) {
File dir = new File(FILE_DIR);
if (!dir.exists()) return;
File[] tsFiles = dir.listFiles();
if (tsFiles == null) return;
int freq = FileDataSource.FREQ_BASE;
for (File file : tsFiles) {
if (!file.isFile()) continue;
output.add(ScanChannel.forFile(freq, file.getName()));
freq += 100;
}
}
/**
* A thread managing a circular buffer that holds stream data to be consumed by player.
* Keeps reading data in from a {@link StreamProvider} to hold enough amount for buffering.
* Started and stopped by {@link #startStream()} and {@link #stopStream()}, respectively.
*/
private class StreamingThread extends Thread {
@Override
public void run() {
byte[] dataBuffer = new byte[READ_BUFFER_SIZE];
synchronized (mCircularBufferMonitor) {
mBytesFetched = 0;
mLastReadPosition = 0;
}
while (true) {
synchronized (mCircularBufferMonitor) {
while ((mBytesFetched - mLastReadPosition + PADDING_SIZE) > CIRCULAR_BUFFER_SIZE
&& mStreaming) {
try {
mCircularBufferMonitor.wait();
} catch (InterruptedException e) {
// Wait again.
Thread.currentThread().interrupt();
}
}
if (!mStreaming) {
break;
}
}
int bytesWritten = mSource.read(dataBuffer);
if (bytesWritten <= 0) {
try {
// When buffer is underrun, we sleep for short time to prevent
// unnecessary CPU draining.
sleep(BUFFER_UNDERRUN_SLEEP_MS);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
continue;
}
mEventDetector.feedTSStream(dataBuffer, 0, bytesWritten);
synchronized (mCircularBufferMonitor) {
int posInBuffer = (int) (mBytesFetched % CIRCULAR_BUFFER_SIZE);
int bytesToCopyInFirstPass = bytesWritten;
if (posInBuffer + bytesToCopyInFirstPass > mCircularBuffer.length) {
bytesToCopyInFirstPass = mCircularBuffer.length - posInBuffer;
}
System.arraycopy(dataBuffer, 0, mCircularBuffer, posInBuffer,
bytesToCopyInFirstPass);
if (bytesToCopyInFirstPass < bytesWritten) {
System.arraycopy(dataBuffer, bytesToCopyInFirstPass, mCircularBuffer, 0,
bytesWritten - bytesToCopyInFirstPass);
}
mBytesFetched += bytesWritten;
mCircularBufferMonitor.notify();
}
}
Log.i(TAG, "Streaming stopped");
mSource.close();
}
}
}