Rotate an YUV byte array on Android

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春和景丽
春和景丽 2020-11-28 08:22

I\'m looking to rotate a YUV frame preview recieved from a Preview Callblack, so far I\'ve founded this post which cointains an algorithm to rotate the frame preview but is

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  •  情歌与酒
    2020-11-28 08:59

    Here are the options to turn a different corner (90, 180, 270):

    public static byte[] rotateYUV420Degree90(byte[] data, int imageWidth, int imageHeight) {
        byte[] yuv = new byte[imageWidth * imageHeight * 3 / 2];
        // Rotate the Y luma
        int i = 0;
        for (int x = 0; x < imageWidth; x++) {
            for (int y = imageHeight - 1; y >= 0; y--) {
                yuv[i] = data[y * imageWidth + x];
                i++;
            }
        }
        // Rotate the U and V color components
        i = imageWidth * imageHeight * 3 / 2 - 1;
        for (int x = imageWidth - 1; x > 0; x = x - 2) {
            for (int y = 0; y < imageHeight / 2; y++) {
                yuv[i] = data[(imageWidth * imageHeight) + (y * imageWidth) + x];
                i--;
                yuv[i] = data[(imageWidth * imageHeight) + (y * imageWidth)
                        + (x - 1)];
                i--;
            }
        }
        return yuv;
    }
    
    private static byte[] rotateYUV420Degree180(byte[] data, int imageWidth, int imageHeight) {
        byte[] yuv = new byte[imageWidth * imageHeight * 3 / 2];
        int i = 0;
        int count = 0;
        for (i = imageWidth * imageHeight - 1; i >= 0; i--) {
            yuv[count] = data[i];
            count++;
        }
        i = imageWidth * imageHeight * 3 / 2 - 1;
        for (i = imageWidth * imageHeight * 3 / 2 - 1; i >= imageWidth
                * imageHeight; i -= 2) {
            yuv[count++] = data[i - 1];
            yuv[count++] = data[i];
        }
        return yuv;
    }
    
    public static byte[] rotateYUV420Degree270(byte[] data, int imageWidth,
                                         int imageHeight) {
        byte[] yuv = new byte[imageWidth * imageHeight * 3 / 2];
        int nWidth = 0, nHeight = 0;
        int wh = 0;
        int uvHeight = 0;
        if (imageWidth != nWidth || imageHeight != nHeight) {
            nWidth = imageWidth;
            nHeight = imageHeight;
            wh = imageWidth * imageHeight;
            uvHeight = imageHeight >> 1;// uvHeight = height / 2
        }
        // ??Y
        int k = 0;
        for (int i = 0; i < imageWidth; i++) {
            int nPos = 0;
            for (int j = 0; j < imageHeight; j++) {
                yuv[k] = data[nPos + i];
                k++;
                nPos += imageWidth;
            }
        }
        for (int i = 0; i < imageWidth; i += 2) {
            int nPos = wh;
            for (int j = 0; j < uvHeight; j++) {
                yuv[k] = data[nPos + i];
                yuv[k + 1] = data[nPos + i + 1];
                k += 2;
                nPos += imageWidth;
            }
        }
        return rotateYUV420Degree180(yuv, imageWidth, imageHeight);
    }
    

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