Question

我已经集成了affectiva库并尝试使用相机流来获取情感。我试图从返回的帧中获取位图，但它总是返回null.Below是代码。

  byte[] imageBytes = ((Frame.ByteArrayFrame) frame).getByteArray();

我们有一些518 kb的数据但是当转换为图像时它返回null。

 Bitmap bitmap = BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
    previewImage.setImageBitmap(bitmap);

我甚至尝试了下面的代码，但又是null位图

Bitmap bmp=frame.getOriginalBitmapFrame();

你能帮我从框架中获取位图吗？

Answer 1

Affectiva的affdexme-android示例应用程序中有一些示例转换方法：

https://github.com/Affectiva/affdexme-android/blob/a0c732fb0378b9c0883d30fa21eaa9cf22b57eed/app/src/main/java/com/affectiva/affdexme/ImageHelper.java#L221

public static Bitmap getBitmapFromFrame(@NonNull final Frame frame) {
    Bitmap bitmap;

    if (frame instanceof Frame.BitmapFrame) {
        bitmap = ((Frame.BitmapFrame) frame).getBitmap();
    } else { //frame is ByteArrayFrame
        switch (frame.getColorFormat()) {
            case RGBA:
                bitmap = getBitmapFromRGBFrame(frame);
                break;
            case YUV_NV21:
                bitmap = getBitmapFromYuvFrame(frame);
                break;
            case UNKNOWN_TYPE:
            default:
                Log.e(LOG_TAG, "Unable to get bitmap from unknown frame type");
                return null;
        }
    }

    if (bitmap == null || frame.getTargetRotation().toDouble() == 0.0) {
        return bitmap;
    } else {
        return rotateBitmap(bitmap, (float) frame.getTargetRotation().toDouble());
    }
}

public static Bitmap getBitmapFromRGBFrame(@NonNull final Frame frame) {
    byte[] pixels = ((Frame.ByteArrayFrame) frame).getByteArray();
    Bitmap bitmap = Bitmap.createBitmap(frame.getWidth(), frame.getHeight(), Bitmap.Config.ARGB_8888);
    bitmap.copyPixelsFromBuffer(ByteBuffer.wrap(pixels));
    return bitmap;
}

public static Bitmap getBitmapFromYuvFrame(@NonNull final Frame frame) {
    byte[] pixels = ((Frame.ByteArrayFrame) frame).getByteArray();
    YuvImage yuvImage = new YuvImage(pixels, ImageFormat.NV21, frame.getWidth(), frame.getHeight(), null);
    return convertYuvImageToBitmap(yuvImage);
}

/**
 * Note: This conversion procedure is sloppy and may result in JPEG compression artifacts
 *
 * @param yuvImage - The YuvImage to convert
 * @return - The converted Bitmap
 */
public static Bitmap convertYuvImageToBitmap(@NonNull final YuvImage yuvImage) {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    yuvImage.compressToJpeg(new Rect(0, 0, yuvImage.getWidth(), yuvImage.getHeight()), 100, out);
    byte[] imageBytes = out.toByteArray();
    try {
        out.close();
    } catch (IOException e) {
        Log.e(LOG_TAG, "Exception while closing output stream", e);
    }
    return BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
}

public static Bitmap rotateBitmap(@NonNull final Bitmap source, final float angle) {
    Matrix matrix = new Matrix();
    matrix.postRotate(angle);
    return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, true);
}

尝试从帧情感中获取图像时，位图为空

1 个答案: