SegmentSpeedProvider.java
/*
* Copyright 2021 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 androidx.media3.transformer;
import static androidx.media3.common.util.Assertions.checkArgument;
import static androidx.media3.extractor.metadata.mp4.SlowMotionData.Segment.BY_START_THEN_END_THEN_DIVISOR;
import androidx.annotation.Nullable;
import androidx.media3.common.C;
import androidx.media3.common.Format;
import androidx.media3.common.Metadata;
import androidx.media3.common.util.Util;
import androidx.media3.extractor.metadata.mp4.SlowMotionData;
import androidx.media3.extractor.metadata.mp4.SlowMotionData.Segment;
import androidx.media3.extractor.metadata.mp4.SmtaMetadataEntry;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSortedMap;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
/** A {@link SpeedProvider} for slow motion segments. */
/* package */ class SegmentSpeedProvider implements SpeedProvider {
/**
* Input frame rate of Samsung Slow motion videos is always 30. See
* go/exoplayer-sef-slomo-video-flattening.
*/
private static final int INPUT_FRAME_RATE = 30;
private final ImmutableSortedMap<Long, Float> speedsByStartTimeUs;
private final float baseSpeedMultiplier;
public SegmentSpeedProvider(Format format) {
float captureFrameRate = getCaptureFrameRate(format);
this.baseSpeedMultiplier =
captureFrameRate == C.RATE_UNSET ? 1 : captureFrameRate / INPUT_FRAME_RATE;
this.speedsByStartTimeUs = buildSpeedByStartTimeUsMap(format, baseSpeedMultiplier);
}
@Override
public float getSpeed(long timeUs) {
checkArgument(timeUs >= 0);
@Nullable Map.Entry<Long, Float> entry = speedsByStartTimeUs.floorEntry(timeUs);
return entry != null ? entry.getValue() : baseSpeedMultiplier;
}
@Override
public long getNextSpeedChangeTimeUs(long timeUs) {
checkArgument(timeUs >= 0);
@Nullable Long nextTimeUs = speedsByStartTimeUs.higherKey(timeUs);
return nextTimeUs != null ? nextTimeUs : C.TIME_UNSET;
}
private static ImmutableSortedMap<Long, Float> buildSpeedByStartTimeUsMap(
Format format, float baseSpeed) {
List<Segment> segments = extractSlowMotionSegments(format);
if (segments.isEmpty()) {
return ImmutableSortedMap.of();
}
TreeMap<Long, Float> speedsByStartTimeUs = new TreeMap<>();
// Start time maps to the segment speed.
for (int i = 0; i < segments.size(); i++) {
Segment currentSegment = segments.get(i);
speedsByStartTimeUs.put(
Util.msToUs(currentSegment.startTimeMs), baseSpeed / currentSegment.speedDivisor);
}
// If the map has an entry at endTime, this is the next segments start time. If no such entry
// exists, map the endTime to base speed because the times after the end time are not in a
// segment.
for (int i = 0; i < segments.size(); i++) {
Segment currentSegment = segments.get(i);
if (!speedsByStartTimeUs.containsKey(Util.msToUs(currentSegment.endTimeMs))) {
speedsByStartTimeUs.put(Util.msToUs(currentSegment.endTimeMs), baseSpeed);
}
}
return ImmutableSortedMap.copyOf(speedsByStartTimeUs);
}
private static float getCaptureFrameRate(Format format) {
@Nullable Metadata metadata = format.metadata;
if (metadata == null) {
return C.RATE_UNSET;
}
for (int i = 0; i < metadata.length(); i++) {
Metadata.Entry entry = metadata.get(i);
if (entry instanceof SmtaMetadataEntry) {
return ((SmtaMetadataEntry) entry).captureFrameRate;
}
}
return C.RATE_UNSET;
}
private static ImmutableList<Segment> extractSlowMotionSegments(Format format) {
List<Segment> segments = new ArrayList<>();
@Nullable Metadata metadata = format.metadata;
if (metadata != null) {
for (int i = 0; i < metadata.length(); i++) {
Metadata.Entry entry = metadata.get(i);
if (entry instanceof SlowMotionData) {
segments.addAll(((SlowMotionData) entry).segments);
}
}
}
return ImmutableList.sortedCopyOf(BY_START_THEN_END_THEN_DIVISOR, segments);
}
}