raw2dng.c

#include <byteswap.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>

unsigned char DNG_HEADER[256 + 61] = {
    0x49,0x49,0x2A,0x00,0x08,0x00,0x00,0x00,0x04,0x00,0x12,0xC6,0x01,0x00,0x04,0x00,
    0x00,0x00,0x01,0x01,0x00,0x00,0x13,0xC6,0x01,0x00,0x04,0x00,0x00,0x00,0x01,0x01,
    0x00,0x00,0x4A,0x01,0x04,0x00,0x01,0x00,0x00,0x00,0x50,0x00,0x00,0x00,0x14,0xC6,
    0x02,0x00,0x11,0x00,0x00,0x00,0x3E,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0x65,
    0x69,0x63,0x68,0x65,0x6E,0x20,0x49,0x4D,0x58,0x33,0x33,0x34,0x4C,0x51,0x52,0x00,
    0x0E,0x00,0xFE,0x00,0x04,0x00,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,
    0x03,0x00,0x01,0x00,0x00,0x00,0x80,0x10,0x00,0x00,0x01,0x01,0x03,0x00,0x01,0x00,
    0x00,0x00,0x78,0x0C,0x00,0x00,0x02,0x01,0x01,0x00,0x01,0x00,0x00,0x00,0x0C,0x00,
    0x00,0x00,0x03,0x01,0x03,0x00,0x01,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x06,0x01,
    0x03,0x00,0x01,0x00,0x00,0x00,0x23,0x80,0x00,0x00,0x11,0x01,0x04,0x00,0x01,0x00,
    0x00,0x00,0x00,0x01,0x00,0x00,0x15,0x01,0x04,0x00,0x01,0x00,0x00,0x00,0x01,0x00,
    0x00,0x00,0x17,0x01,0x04,0x00,0x01,0x00,0x00,0x00,0x00,0x9A,0x34,0x01,0x1C,0x01,
    0x03,0x00,0x01,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x8D,0x82,0x03,0x00,0x02,0x00,
    0x00,0x00,0x02,0x00,0x02,0x00,0x8E,0x82,0x01,0x00,0x04,0x00,0x00,0x00,0x00,0x01,
    0x01,0x02,0x1A,0xC6,0x03,0x00,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x1D,0xC6,
    0x03,0x00,0x01,0x00,0x00,0x00,0xFF,0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    0xff,0xd8,
    0xff,0xc3,0x00,0x0b, //Start of Frame
    0x0C, //Bitdepth
    0x0c,0x7a, //Height
    0x10,0x80, //Width
    0x01, //No. of Components
    0x00,0x11,0x00,
    0xff,0xc4,0x00,0x20, //Define Huffman
    0x00, //Table index
    0x00,0x01,0x04,0x02,0x03,0x01,0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    0x05,0x04,0x06,0x03,0x07,0x02,0x08,0x01,0x09,0x00,0x0a,0x0b,0x0c, //Leaf Value
    0,0,0,0,0,0,0,0,0,0
};

void update_dng_header(unsigned short width, unsigned short height, unsigned char bitdepth, bool comp) {
    *(unsigned short*) (DNG_HEADER + 0x66) = width;
    *(unsigned short*) (DNG_HEADER + 0x72) = height;
    DNG_HEADER[0x7E] = bitdepth;
    *(unsigned int*) (DNG_HEADER + 0xBA) = (width * height * bitdepth) >> 3;
    // Black level
    *(unsigned short*) (DNG_HEADER + 0xEA) = 15;
    // White level
    *(unsigned short*) (DNG_HEADER + 0xF6) = (1 << bitdepth) - 1;
    unsigned char * LJPG_HEADER = DNG_HEADER + 256;
    if (comp) {
        LJPG_HEADER[6] = bitdepth;
        LJPG_HEADER[7] = height >> 8;
        LJPG_HEADER[8] = height & 0xFF;
        LJPG_HEADER[9] = width >> 8;
        LJPG_HEADER[10] = width & 0xFF;
        LJPG_HEADER[18] = 20 + bitdepth;
    }
}

int main(int argc, char **argv) {
    int res;
    unsigned short width, height;
    width = atoi(argv[1]);
    height = atoi(argv[2]);
    unsigned char bitdepth = atoi(argv[3]);
    char * raw_fname = argv[4];
    char * dng_fname = argv[5];
    FILE * raw_file = fopen(raw_fname, "rb");
    unsigned short * raw_buf = malloc(width * height * sizeof(unsigned short));
    fread(raw_buf, sizeof(unsigned short), width * height, raw_file);

    unsigned char * out_buf = malloc((width * height * bitdepth) >> 3);
    int j = 0;
    unsigned char bits = 0;
    unsigned short bitstream = 0;

    unsigned int hist[4096] = {0};
    for (int i = 0; i < width * height; i++) {
        // Left justified 16 bit pixel
        unsigned short pix_val = __bswap_16(raw_buf[i]);
        hist[pix_val >> 4]++;
        bitstream |= pix_val >> bits;
        bits += 12;
        while (bits >= 8) {
            out_buf[j] = bitstream >> 8;
            bitstream <<= 8;
            bits -= 8;
            j++;
        }
    }
    free(raw_buf);

    update_dng_header(width, height, bitdepth, 0);

    FILE * outfile = fopen(dng_fname, "wb");
    fwrite(DNG_HEADER, 1, 256, outfile);
    fwrite(out_buf, 1, j, outfile);
    free(out_buf);
    fclose(outfile);

    // Analyze histogram
    float total_val = 0.0;
    int highlight_count = 0;
    int one_thousandths = width * height / 10000;
    for (int i = 4095; i >= 0; i--) {
        if (hist[i]) {
            highlight_count += hist[i];
            total_val += ((float) hist[i]) * i;
            if (highlight_count > one_thousandths) {
                total_val /= highlight_count;
                printf("%f\n", total_val);
                break;
            }
        }
    }

    return 0;
}