android - 如何在android中将位图转换为nv21字节[]数组

Question

我已经尝试过这种方法进行转换，但结果图像已损坏

ByteArrayOutputStream outputStream=new ByteArrayOutputStream();
                scaled.compress(Bitmap.CompressFormat.JPEG,100, outputStream);
                byte [] bytes = outp`enter code here`utStream.toByteArray();
         ByteArrayOutputStream out = new ByteArrayOutputStream();
                YuvImage image = new YuvImage(bytes, ImageFormat.NV21, inputWidth, inputHeight, null);
                int quality = 100;   //
        
        image.compressToJpeg(new Rect(0, 0, inputWidth, inputHeight), quality, out);
                byte[] yuv = out.toByteArray();

Answer 1

我使用以下代码：

public interface ImageTestUtils {

static byte[] getNV21(int inputWidth, int inputHeight, Bitmap scaled) {

    int[] argb = new int[inputWidth * inputHeight];

    scaled.getPixels(argb, 0, inputWidth, 0, 0, inputWidth, inputHeight);

    byte[] yuv = new byte[inputWidth * inputHeight * 3 / 2];
    encodeYUV420SP(yuv, argb, inputWidth, inputHeight);

    scaled.recycle();

    return yuv;
}

static void encodeYUV420SP(byte[] yuv420sp, int[] argb, int width, int height) {
    final int frameSize = width * height;

    int yIndex = 0;
    int uvIndex = frameSize;

    int a, R, G, B, Y, U, V;
    int index = 0;
    for (int j = 0; j < height; j++) {
        for (int i = 0; i < width; i++) {

            a = (argb[index] & 0xff000000) >> 24; // a is not used obviously
            R = (argb[index] & 0xff0000) >> 16;
            G = (argb[index] & 0xff00) >> 8;
            B = (argb[index] & 0xff) >> 0;

            // well known RGB to YUV algorithm
            Y = ((66 * R + 129 * G + 25 * B + 128) >> 8) + 16;
            U = ((-38 * R - 74 * G + 112 * B + 128) >> 8) + 128;
            V = ((112 * R - 94 * G - 18 * B + 128) >> 8) + 128;

            // NV21 has a plane of Y and interleaved planes of VU each sampled by a factor of 2
            //    meaning for every 4 Y pixels there are 1 V and 1 U.  Note the sampling is every other
            //    pixel AND every other scanline.
            yuv420sp[yIndex++] = (byte) ((Y < 0) ? 0 : ((Y > 255) ? 255 : Y));
            if (j % 2 == 0 && index % 2 == 0) {
                yuv420sp[uvIndex++] = (byte) ((V < 0) ? 0 : ((V > 255) ? 255 : V));
                yuv420sp[uvIndex++] = (byte) ((U < 0) ? 0 : ((U > 255) ? 255 : U));
            }

            index++;
        }
    }
}

}