Set up an external video source

package com.mapbox.vision.examples;
 
import android.graphics.Bitmap;
import android.media.MediaMetadataRetriever;
import android.os.Handler;
import android.os.HandlerThread;
 
import com.mapbox.vision.VisionManager;
import com.mapbox.vision.mobile.core.interfaces.VisionEventsListener;
import com.mapbox.vision.mobile.core.models.AuthorizationStatus;
import com.mapbox.vision.mobile.core.models.Camera;
import com.mapbox.vision.mobile.core.models.Country;
import com.mapbox.vision.mobile.core.models.FrameSegmentation;
import com.mapbox.vision.mobile.core.models.classification.FrameSignClassifications;
import com.mapbox.vision.mobile.core.models.detection.FrameDetections;
import com.mapbox.vision.mobile.core.models.frame.ImageFormat;
import com.mapbox.vision.mobile.core.models.frame.ImageSize;
import com.mapbox.vision.mobile.core.models.position.VehicleState;
import com.mapbox.vision.mobile.core.models.road.RoadDescription;
import com.mapbox.vision.mobile.core.models.world.WorldDescription;
import com.mapbox.vision.video.videosource.VideoSource;
import com.mapbox.vision.video.videosource.VideoSourceListener;
import com.mapbox.vision.view.VisionView;
 
import org.jetbrains.annotations.NotNull;
 
import java.nio.ByteBuffer;
import java.util.concurrent.TimeUnit;
 
/**
* Example shows how Vision SDK can work with external video source. This can be some custom camera implementation or any
* other source of frames - video, set of pictures, etc.
*/
public class ExternalVideoSourceActivity extends BaseActivity {
 
// Video file that will be processed.
private static final String PATH_TO_VIDEO_FILE = "path_to_video_file";
 
private VideoSourceListener videoSourceListener;
private VisionView visionView;
private HandlerThread handlerThread = new HandlerThread("VideoDecode");
private boolean visionManagerWasInit = false;
 
// VideoSource that will play the file.
private VideoSource customVideoSource = new VideoSource() {
@Override
public void attach(@NotNull VideoSourceListener videoSourceListener) {
// video source is attached, we can start decoding frames from video and feeding them to Vision SDK.
ExternalVideoSourceActivity.this.videoSourceListener = videoSourceListener;
handlerThread.start();
new Handler(handlerThread.getLooper()).post(() -> startFileVideoSource());
}
 
@Override
public void detach() {
videoSourceListener = null;
handlerThread.quitSafely();
}
};
 
// VisionEventsListener handles events from Vision SDK on background thread.
private VisionEventsListener visionEventsListener = new VisionEventsListener() {
 
@Override
public void onAuthorizationStatusUpdated(@NotNull AuthorizationStatus authorizationStatus) {
}
 
@Override
public void onFrameSegmentationUpdated(@NotNull FrameSegmentation frameSegmentation) {
}
 
@Override
public void onFrameDetectionsUpdated(@NotNull FrameDetections frameDetections) {
 
}
 
@Override
public void onFrameSignClassificationsUpdated(@NotNull FrameSignClassifications frameSignClassifications) {
}
 
@Override
public void onRoadDescriptionUpdated(@NotNull RoadDescription roadDescription) {
}
 
@Override
public void onWorldDescriptionUpdated(@NotNull WorldDescription worldDescription) {
}
 
@Override
public void onVehicleStateUpdated(@NotNull VehicleState vehicleState) {
}
 
@Override
public void onCameraUpdated(@NotNull Camera camera) {
}
 
@Override
public void onCountryUpdated(@NotNull Country country) {
}
 
@Override
public void onUpdateCompleted() {
}
};
 
@Override
protected void initViews() {
setContentView(R.layout.activity_main);
visionView = findViewById(R.id.vision_view);
}
 
@Override
protected void onPermissionsGranted() {
startVisionManager();
}
 
@Override
protected void onStart() {
super.onStart();
startVisionManager();
}
 
@Override
protected void onStop() {
super.onStop();
stopVisionManager();
}
 
@Override
protected void onResume() {
super.onResume();
visionView.onResume();
}
 
@Override
protected void onPause() {
super.onPause();
visionView.onPause();
}
 
private void startVisionManager() {
if (allPermissionsGranted() && !visionManagerWasInit) {
VisionManager.create(customVideoSource);
visionView.setVisionManager(VisionManager.INSTANCE);
VisionManager.setVisionEventsListener(visionEventsListener);
VisionManager.start();
 
visionManagerWasInit = true;
}
}
 
private void stopVisionManager() {
if (visionManagerWasInit) {
VisionManager.stop();
VisionManager.destroy();
 
visionManagerWasInit = false;
}
}
 
/**
* Decodes video source frame by frame and feeds frames to Vision SDK.
*/
private void startFileVideoSource() {
// Use MediaMetadataRetriever to decode video.
// It isn't the fastest approach to decode videos and you probably want some other method.
// if FPS is important (eg. MediaCodec).
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
retriever.setDataSource(PATH_TO_VIDEO_FILE);
 
// Get video frame size.
int frameWidth = Integer.parseInt(retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_WIDTH));
int frameHeight = Integer.parseInt(retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_HEIGHT));
ImageSize imageSize = new ImageSize(frameWidth, frameHeight);
// ByteBuffer to hold RGBA bytes.
ByteBuffer rgbaByteBuffer = ByteBuffer.allocateDirect(frameWidth * frameHeight * 4);
 
// Get duration.
long duration = Long.parseLong(retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION));
 
try {
// Get frames one by one with 1 second intervals.
for (int seconds = 0; seconds < duration; seconds++) {
Bitmap bitmap = retriever
.getFrameAtTime(
TimeUnit.SECONDS.toMicros(seconds),
MediaMetadataRetriever.OPTION_CLOSEST
)
.copy(Bitmap.Config.ARGB_8888, false);
 
bitmap.copyPixelsToBuffer(rgbaByteBuffer);
 
videoSourceListener.onNewFrame(
new VideoSourceListener.FrameHolder.ByteBufferHolder(rgbaByteBuffer),
ImageFormat.RGBA,
imageSize
);
rgbaByteBuffer.clear();
}
} catch (RuntimeException e) {
e.printStackTrace();
} finally {
try {
retriever.release();
} catch (RuntimeException e) {
e.printStackTrace();
}
}
}
}