package kaka.cakelight;
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
import java.io.*;
+import java.util.Optional;
-public class FrameGrabber {
+import static kaka.cakelight.Main.log;
+
+public class FrameGrabber implements Closeable {
private Configuration config;
private File file;
private int bytesPerFrame;
private InputStream fileStream;
+ private final ByteArrayOutputStream bufferedBytes = new ByteArrayOutputStream();
private FrameGrabber() {
}
- public static FrameGrabber from(Configuration config) {
+ public static FrameGrabber from(File videoDevice, Configuration config) {
FrameGrabber fg = new FrameGrabber();
fg.config = config;
- fg.file = new File(config.video.device);
+ fg.file = videoDevice;
fg.bytesPerFrame = config.video.width * config.video.height * config.video.bpp;
+ fg.prepare();
return fg;
}
- public boolean prepare() {
+ private boolean prepare() {
try {
fileStream = new FileInputStream(file);
return true;
} catch (FileNotFoundException e) {
+ // TODO: handle java.io.FileNotFoundException: /dev/video1 (Permission denied)
e.printStackTrace();
return false;
}
}
- public Frame grabFrame() {
+ /**
+ * Must be run in the same thread as {@link #prepare}.
+ */
+ public Optional<VideoFrame> grabFrame() {
try {
- byte[] data = new byte[bytesPerFrame];
- int count = fileStream.read(data);
- System.out.println("count = " + count);
- return Frame.of(data, config);
+ byte[] data;
+ if (config.video.mjpg) {
+ byte[] jpgData = readStreamingJpgData();
+ if (jpgData == null) {
+ return Optional.empty();
+ }
+ saveTemporaryJpgFile(jpgData);
+ byte[] bmpData = convertJpgFileToByteArray();
+ if (bmpData == null) {
+ return Optional.empty();
+ }
+ data = bmpData;
+ } else {
+ data = new byte[bytesPerFrame];
+ int count = fileStream.read(data);
+ if (count != bytesPerFrame) {
+ log("Expected to read " + bytesPerFrame + " bytes per frame but read " + count);
+ }
+ }
+
+ return Optional.of(VideoFrame.of(data, config));
} catch (IOException e) {
e.printStackTrace();
}
- return null;
+ return Optional.empty();
}
- public void close() {
- try {
- fileStream.close();
- } catch (IOException e) {
- e.printStackTrace();
+ private byte[] readStreamingJpgData() throws IOException {
+ byte[] data;
+ byte[] batch = new byte[1024];
+ boolean lastByteIsXX = false;
+ loop:
+ while (true) {
+ int batchCount = fileStream.read(batch);
+ if (batchCount == -1) {
+ return null;
+ }
+ if (lastByteIsXX) {
+ if (batch[0] == (byte) 0xd8) {
+ data = bufferedBytes.toByteArray();
+ bufferedBytes.reset();
+ bufferedBytes.write(0xff);
+ bufferedBytes.write(batch, 0, batchCount);
+ break;
+ }
+ bufferedBytes.write(0xff);
+ }
+ for (int i = 0; i < batchCount - 1; i++) {
+ if (batch[i] == (byte) 0xff && batch[i + 1] == (byte) 0xd8) { // start of jpeg
+ if (i > 0) {
+ bufferedBytes.write(batch, 0, i);
+ }
+ data = bufferedBytes.toByteArray();
+ bufferedBytes.reset();
+ bufferedBytes.write(batch, i, batchCount - i);
+ break loop;
+ }
+ }
+ lastByteIsXX = batch[batchCount - 1] == (byte) 0xff;
+ bufferedBytes.write(batch, 0, batchCount - (lastByteIsXX ? 1 : 0));
}
+ return data;
+ }
+
+ private void saveTemporaryJpgFile(byte[] data) throws IOException {
+ try (FileOutputStream fos = new FileOutputStream("/tmp/cakelight-video-stream.jpg")) {
+ fos.write(data);
+ }
+ }
+
+ private byte[] convertJpgFileToByteArray() throws IOException {
+ BufferedImage image = ImageIO.read(new File("/tmp/cakelight-video-stream.jpg"));
+ if (image != null) { // will almost always be null the first time
+ try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
+ ImageIO.write(image, "bmp", baos);
+ baos.flush();
+ return baos.toByteArray();
+ }
+ } else {
+ return null;
+ }
+ }
+
+ @Override
+ public void close() throws IOException {
+ fileStream.close();
}
}