java - 网络摄像头 api : Maximizing the 720p capture

Question

我正在尝试通过外部摄像头 Logitec C922 捕捉视频记录。使用 java，我可以通过网络摄像头 api 实现这一点。

    <dependency>
        <groupId>com.github.sarxos</groupId>
        <artifactId>webcam-capture</artifactId>
        <version>0.3.10</version>
    </dependency>
    <dependency>
        <groupId>xuggle</groupId>
        <artifactId>xuggle-xuggler</artifactId>
        <version>5.4</version>
    </dependency>

然而，对于我来说，我无法让它以 60FPS 的速度录制。视频在存储时随机卡顿，一点也不流畅。

我可以使用以下详细信息连接到相机。

final List<Webcam> webcams = Webcam.getWebcams();

for (final Webcam cam : webcams) {
    if (cam.getName().contains("C922")) {
        System.out.println("### Logitec C922 cam found");
        webcam = cam;
        break;
    }
}

我将凸轮的大小设置如下:

final Dimension[] nonStandardResolutions = new Dimension[] { WebcamResolution.HD720.getSize(), };
webcam.setCustomViewSizes(nonStandardResolutions);
webcam.setViewSize(WebcamResolution.HD720.getSize());
webcam.open(true);

然后我捕捉图像:

while (continueRecording) {
    // capture the webcam image
    final BufferedImage webcamImage = ConverterFactory.convertToType(webcam.getImage(),
                    BufferedImage.TYPE_3BYTE_BGR);
    final Date timeOfCapture = new Date();

    // convert the image and store
    final IConverter converter = ConverterFactory.createConverter(webcamImage, IPixelFormat.Type.YUV420P);
    final IVideoPicture frame = converter.toPicture(webcamImage,
                    (System.currentTimeMillis() - start) * 1000);

    frame.setKeyFrame(false);
    frame.setQuality(0);
    writer.encodeVideo(0, frame);

}

我的writer定义如下:

final Dimension size = WebcamResolution.HD720.getSize();
final IMediaWriter writer = ToolFactory.makeWriter(videoFile.getName());
writer.addVideoStream(0, 0, ICodec.ID.CODEC_ID_H264, size.width, size.height);

老实说，我不确定我的代码中的什么会导致这种情况。鉴于我降低了分辨率，我没有遇到任何问题。 ( 480p ) 问题可能出在我使用的代码上吗？

Answer 1

正如一些评论提到的，引入队列确实解决了问题。以下是执行所需步骤的一般逻辑。请注意，我已将我的代码设置为较低的分辨率，因为它允许我每秒捕获 100FPS。根据需要进行调整。

链接图像/视频捕获的类和编辑它的类:

public class WebcamRecorder {

    final Dimension size = WebcamResolution.QVGA.getSize();
    final Stopper stopper = new Stopper();

    public void startRecording() throws Exception {

        final Webcam webcam = Webcam.getDefault();
        webcam.setViewSize(size);
        webcam.open(true);

        final BlockingQueue<CapturedFrame> queue = new LinkedBlockingQueue<CapturedFrame>();
        final Thread recordingThread = new Thread(new RecordingThread(queue, webcam, stopper));
        final Thread imageProcessingThread = new Thread(new ImageProcessingThread(queue, size));

        recordingThread.start();
        imageProcessingThread.start();
    }

    public void stopRecording() {
        stopper.setStop(true);
    }

}

录音线程:

public void run() {
    try {
        System.out.println("## capturing images began");
        while (true) {
            final BufferedImage webcamImage = ConverterFactory.convertToType(webcam.getImage(),
                    BufferedImage.TYPE_3BYTE_BGR);
            final Date timeOfCapture = new Date();
            queue.put(new CapturedFrame(webcamImage, timeOfCapture, false));
            if (stopper.isStop()) {
                System.out.println("### signal to stop capturing images received");
                queue.put(new CapturedFrame(null, null, true));
                break;
            }
        }
    } catch (InterruptedException e) {
        System.out.println("### threading issues during recording:: " + e.getMessage());
    } finally {
        System.out.println("## capturing images end");
        if (webcam.isOpen()) {
            webcam.close();
        }
    }
}

图像处理线程:

public void run() {
    writer.addVideoStream(0, 0, ICodec.ID.CODEC_ID_H264, size.width, size.height);
    try {
        int frameIdx = 0;
        final long start = System.currentTimeMillis();
        while (true) {
            final CapturedFrame capturedFrame = queue.take();
            if (capturedFrame.isEnd()) {
                break;
            }
            final BufferedImage webcamImage = capturedFrame.getImage();
            size.height);

            // convert the image and store
            final IConverter converter = ConverterFactory.createConverter(webcamImage, IPixelFormat.Type.YUV420P);
            final long end = System.currentTimeMillis();
            final IVideoPicture frame = converter.toPicture(webcamImage, (end - start) * 1000);

            frame.setKeyFrame((frameIdx++ == 0));
            frame.setQuality(0);
            writer.encodeVideo(0, frame);
        }
    } catch (final InterruptedException e) {
        System.out.println("### threading issues during image processing:: " + e.getMessage());
    } finally {
        if (writer != null) {
            writer.close();
        }
    }

它的工作方式非常简单。 WebcamRecord 类创建一个在视频捕获和图像处理之间共享的队列实例。 RecordingThread 将 bufferedImages 发送到队列(在我的例子中，它是一个 pojo，称为 CapturedFrame(其中有一个 BufferedImage))。 ImageProcessingThread 将监听并从队列中拉取数据。如果它没有收到写入应该结束的信号，则循环永远不会结束。