1 files changed, 163 insertions, 0 deletions
diff --git a/usbtuner/src/com/android/usbtuner/exoplayer/DefaultSampleSource.java b/usbtuner/src/com/android/usbtuner/exoplayer/DefaultSampleSource.java
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+++ b/usbtuner/src/com/android/usbtuner/exoplayer/DefaultSampleSource.java
@@ -0,0 +1,163 @@
+/*
+ * 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.exoplayer;
+
+import com.google.android.exoplayer.C;
+import com.google.android.exoplayer.MediaFormatHolder;
+import com.google.android.exoplayer.SampleHolder;
+import com.google.android.exoplayer.SampleSource;
+import com.google.android.exoplayer.TrackInfo;
+import com.google.android.exoplayer.util.Assertions;
+
+import java.io.IOException;
+
+/** {@link SampleSource} that extracts sample data using a {@link SampleExtractor}. */
+public final class DefaultSampleSource implements SampleSource {
+
+    private static final int TRACK_STATE_DISABLED = 0;
+    private static final int TRACK_STATE_ENABLED = 1;
+    private static final int TRACK_STATE_FORMAT_SENT = 2;
+
+    private final SampleExtractor sampleExtractor;
+
+    private TrackInfo[] trackInfos;
+    private boolean prepared;
+    private int remainingReleaseCount;
+    private int[] trackStates;
+    private boolean[] pendingDiscontinuities;
+
+    private long seekPositionUs;
+
+    /**
+    * Creates a new sample source that extracts samples using {@code sampleExtractor}. Specifies the
+    * {@code downstreamRendererCount} to ensure that the sample source is released only when all
+    * downstream renderers have been released.
+    *
+    * @param sampleExtractor a sample extractor for accessing media samples
+    * @param downstreamRendererCount the number of track renderers dependent on this sample source
+    */
+    public DefaultSampleSource(SampleExtractor sampleExtractor, int downstreamRendererCount) {
+        this.sampleExtractor = Assertions.checkNotNull(sampleExtractor);
+        this.remainingReleaseCount = downstreamRendererCount;
+    }
+
+    @Override
+    public boolean prepare(long positionUs) throws IOException {
+        if (prepared) {
+            return true;
+        }
+
+        if (sampleExtractor.prepare()) {
+            prepared = true;
+            trackInfos = sampleExtractor.getTrackInfos();
+            trackStates = new int[trackInfos.length];
+            pendingDiscontinuities = new boolean[trackInfos.length];
+        }
+
+        return prepared;
+    }
+
+    @Override
+    public int getTrackCount() {
+        Assertions.checkState(prepared);
+        return trackInfos.length;
+    }
+
+    @Override
+    public TrackInfo getTrackInfo(int track) {
+        Assertions.checkState(prepared);
+        return trackInfos[track];
+    }
+
+    @Override
+    public void enable(int track, long positionUs) {
+        Assertions.checkState(prepared);
+        Assertions.checkState(trackStates[track] == TRACK_STATE_DISABLED);
+        trackStates[track] = TRACK_STATE_ENABLED;
+        sampleExtractor.selectTrack(track);
+        seekToUsInternal(positionUs, positionUs != 0);
+    }
+
+    @Override
+    public void disable(int track) {
+        Assertions.checkState(prepared);
+        Assertions.checkState(trackStates[track] != TRACK_STATE_DISABLED);
+        sampleExtractor.deselectTrack(track);
+        pendingDiscontinuities[track] = false;
+        trackStates[track] = TRACK_STATE_DISABLED;
+    }
+
+    @Override
+    public boolean continueBuffering(long positionUs) throws IOException {
+        return sampleExtractor.continueBuffering(positionUs);
+    }
+
+    @Override
+    public int readData(int track, long positionUs, MediaFormatHolder formatHolder,
+      SampleHolder sampleHolder, boolean onlyReadDiscontinuity) throws IOException {
+        Assertions.checkState(prepared);
+        Assertions.checkState(trackStates[track] != TRACK_STATE_DISABLED);
+        if (pendingDiscontinuities[track]) {
+            pendingDiscontinuities[track] = false;
+            return DISCONTINUITY_READ;
+        }
+        if (onlyReadDiscontinuity) {
+            return NOTHING_READ;
+        }
+        if (trackStates[track] != TRACK_STATE_FORMAT_SENT) {
+            sampleExtractor.getTrackMediaFormat(track, formatHolder);
+            trackStates[track] = TRACK_STATE_FORMAT_SENT;
+            return FORMAT_READ;
+        }
+
+        seekPositionUs = C.UNKNOWN_TIME_US;
+        return sampleExtractor.readSample(track, sampleHolder);
+    }
+
+    @Override
+    public void seekToUs(long positionUs) {
+        Assertions.checkState(prepared);
+        seekToUsInternal(positionUs, false);
+    }
+
+    @Override
+    public long getBufferedPositionUs() {
+        Assertions.checkState(prepared);
+        return sampleExtractor.getBufferedPositionUs();
+    }
+
+    @Override
+    public void release() {
+        Assertions.checkState(remainingReleaseCount > 0);
+        if (--remainingReleaseCount == 0) {
+            sampleExtractor.release();
+        }
+    }
+
+    private void seekToUsInternal(long positionUs, boolean force) {
+        // Unless forced, avoid duplicate calls to the underlying extractor's seek method in the case
+        // that there have been no interleaving calls to readSample.
+        if (force || seekPositionUs != positionUs) {
+            seekPositionUs = positionUs;
+            sampleExtractor.seekTo(positionUs);
+            for (int i = 0; i < trackStates.length; ++i) {
+                if (trackStates[i] != TRACK_STATE_DISABLED) {
+                    pendingDiscontinuities[i] = true;
+                }
+            }
+        }
+    }
+}