Android camera开发总结

1. 缩放RGBA

    private byte[] scaleRGBA(final byte[] data
            , int scale
            , final int cameraWidth
            , final int cameraHeight
            , int[] outSize) {
        int w = cameraWidth / scale;
        int h = cameraHeight / scale;
        outSize[0] = w;
        outSize[1] = h;
        int index = 0;
        byte[] result = new byte[w * h * 4];
        for (int j = 0; j < cameraHeight; j += scale) {
            int width_count = cameraWidth * 4;
            int offset = j * width_count;
            for (int i = 0; i < width_count; i += 4 * scale) {
                result[index++] = data[offset + i];
                result[index++] = data[offset + i + 1];
                result[index++] = data[offset + i + 2];
                result[index++] = data[offset + i + 3];
            }
        }
        return result;
    }

2. 缩放YUV

    public static byte[] scaleUV420(byte[] data, int width, int height, int scale, int[] sz) {
        Log.e("wangshuai", "data length is " + data.length);
        int w = width / scale;
        int h = height / scale;

        if (w % 2 == 1) {
            w += 1;
        }
        if (h % 2 == 1) {
            h += 1;
        }
        sz[0] = w;
        sz[1] = h;
        byte[] yuv = new byte[w * h + w * h / 2];
        int i = 0;
        for (int k = 0; k < height; k += scale) {
            for (int m = 0; m < width; m += scale) {
                yuv[i] = data[k * width + m];
                i++;
            }
        }
        int size = width * height;
        i = w * h;
        for (int k = 0; k < height / 2; k += scale) {
            for (int m = 0; m < width; m += (2 * scale)) {
                if(i< yuv.length) {
                    yuv[i] = data[size + (k * width) + m];
                    i++;
                }
                if(i< yuv.length) {
                    yuv[i] = data[size + (k * width) + m + 1];
                    i++;
                }
            }
        }
        assert (i == size + size / 2);
        return yuv;
    }

3. YUV转bitmap

 static public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width,
                                      int height) {
        Log.e("wangshuai", "decodeYUV420SP width is " + width);
        Log.e("wangshuai", "decodeYUV420SP height is " + height);
        Log.e("wangshuai", "decodeYUV420SP yuv420sp is " + yuv420sp.length);
        final int frameSize = width * height;

        for (int j = 0, yp = 0; j < height; j++) {
            int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
            for (int i = 0; i < width; i++, yp++) {
                int y = (0xff & ((int) yuv420sp[yp])) - 16;
                if (y < 0)
                    y = 0;
                if ((i & 1) == 0) {
                    v = (0xff & yuv420sp[uvp++]) - 128;
                    u = (0xff & yuv420sp[uvp++]) - 128;
                }

                int y1192 = 1192 * y;
                int r = (y1192 + 1634 * v);
                int g = (y1192 - 833 * v - 400 * u);
                int b = (y1192 + 2066 * u);

                if (r < 0)
                    r = 0;
                else if (r > 262143)
                    r = 262143;
                if (g < 0)
                    g = 0;
                else if (g > 262143)
                    g = 262143;
                if (b < 0)
                    b = 0;
                else if (b > 262143)
                    b = 262143;

                rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) &
                        0xff00) | ((b >> 10) & 0xff);
            }
        }
    }