Let’s now see how to create a video from scratch. As input, we will use sequential snapshots from our desktop. This can be used for a rudimentary screen recording application. This is very important when you want to make your want to create individual frames and make your own custom video. We are going to use Xuggler for that.
In short, to create video from image frames with Xuggler, one should follow these basic steps:
- Make a
IMediaWriterto write the file usingToolFactory.makeWriter(outputFilename). - Get the screen
Dimensionyou are working with usingToolkit.getDefaultToolkit().getScreenSize(). - Tell the
IMediaWriterthat we’re going to add one video stream, with id 0,at position 0, and that it will have a fixed frame rate of FRAME_RATE callingwriter.addVideoStream(0, 0,ICodec.ID.CODEC_ID_MPEG4,screenBounds.width/2,screenBounds.height/2); - Use
Robot.createScreenCaptureto take Desktop screenshots and convert it the right image type. - Encode the image to stream using
writer.encodeVideo.
Let’s see the code snippet that follows:
package com.javacodegeeks.xuggler;
import java.awt.AWTException;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.util.concurrent.TimeUnit;
import com.xuggle.mediatool.IMediaWriter;
import com.xuggle.mediatool.ToolFactory;
import com.xuggle.xuggler.ICodec;
public class ScreenRecordingExample {
private static final double FRAME_RATE = 50;
private static final int SECONDS_TO_RUN_FOR = 20;
private static final String outputFilename = "c:/mydesktop.mp4";
private static Dimension screenBounds;
public static void main(String[] args) {
// let's make a IMediaWriter to write the file.
final IMediaWriter writer = ToolFactory.makeWriter(outputFilename);
screenBounds = Toolkit.getDefaultToolkit().getScreenSize();
// We tell it we're going to add one video stream, with id 0,
// at position 0, and that it will have a fixed frame rate of FRAME_RATE.
writer.addVideoStream(0, 0, ICodec.ID.CODEC_ID_MPEG4,
screenBounds.width/2, screenBounds.height/2);
long startTime = System.nanoTime();
for (int index = 0; index < SECONDS_TO_RUN_FOR * FRAME_RATE; index++) {
// take the screen shot
BufferedImage screen = getDesktopScreenshot();
// convert to the right image type
BufferedImage bgrScreen = convertToType(screen,
BufferedImage.TYPE_3BYTE_BGR);
// encode the image to stream #0
writer.encodeVideo(0, bgrScreen, System.nanoTime() - startTime,
TimeUnit.NANOSECONDS);
// sleep for frame rate milliseconds
try {
Thread.sleep((long) (1000 / FRAME_RATE));
}
catch (InterruptedException e) {
// ignore
}
}
// tell the writer to close and write the trailer if needed
writer.close();
}
public static BufferedImage convertToType(BufferedImage sourceImage, int targetType) {
BufferedImage image;
// if the source image is already the target type, return the source image
if (sourceImage.getType() == targetType) {
image = sourceImage;
}
// otherwise create a new image of the target type and draw the new image
else {
image = new BufferedImage(sourceImage.getWidth(),
sourceImage.getHeight(), targetType);
image.getGraphics().drawImage(sourceImage, 0, 0, null);
}
return image;
}
private static BufferedImage getDesktopScreenshot() {
try {
Robot robot = new Robot();
Rectangle captureSize = new Rectangle(screenBounds);
return robot.createScreenCapture(captureSize);
}
catch (AWTException e) {
e.printStackTrace();
return null;
}
}
}
This was an example on how to create video from image frames with Xuggler.
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