display.c

在linux下开发音频播放器的源代码

  }
  else if ( bpp==24 )
  {
     dither_frame=ditherframeRGB;
     dither_even =dithertopRGB;
     dither_odd  =ditherbotRGB;
     init_ditherRGB();
  }
  else
     error("unsuported dither type");

  bpp/=8;
  if(!(dithered_image = (unsigned char *)malloc(bpp*coded_picture_width*
                                                coded_picture_height)))
    error("malloc failed");

  if(!(dithered_image2 = (unsigned char *)malloc(bpp*coded_picture_width*
                                                 coded_picture_height)))
    error("malloc failed");

  for (i=-8; i<256+8; i++)
  {
    v = i>>4;
    if (v<1)
      v = 1;
    else if (v>14)
      v = 14;
    ytab[i+8] = v<<4;
  }

  for (i=0; i<128+16; i++)
  {
    v = (i-40)>>4;
    if (v<0)
      v = 0;
    else if (v>3)
      v = 3;
    utab[i] = v<<2;
    vtab[i] = v;
  }

  for (i=0; i<256; i++)
     pixel[i]=i;
}

////////////////////////////////////////////////////////////////////////////
//
// RGB dithering routines
//
////////////////////////////////////////////////////////////////////////////

#define BITS	8
#define ONE     ((int) 1)
#define CONST_SCALE	(ONE << BITS)
#define ROUND_FACTOR	(ONE << (BITS-1))
#define UP(x)	(((int)(x)) << BITS)
#define DOWN(x)	(((x) + ROUND_FACTOR) >> BITS)
#define FIX(x)  ((int) ((x)*CONST_SCALE + 0.5))
#define CLAMP(ll,x,ul)	( ((x)<(ll)) ?(ll):( ((x)>(ul)) ?(ul):(x)))

static int Cr_r_tab[256];
static int Cb_g_tab[256];
static int Cr_g_tab[256];
static int Cb_b_tab[256];
static int Cy_tab  [256];

//
// initialize tables used in YCbCr -> RGB conversion
//
static void init_ditherRGB()
{
   int CR, CB, i;

   for (i=0; i<256; i++)
   {
      CB = CR = i - 128;

      Cr_r_tab[i] =  FIX(1.40200) * CR;
      Cb_g_tab[i] = -FIX(0.34414) * CB;
      Cr_g_tab[i] = -FIX(0.71414) * CR;
      Cb_b_tab[i] =  FIX(1.77200) * CB;
      Cy_tab  [i] =  FIX(255.0/219.0) * i;
   }
}

static void ditherframeRGB(src)
unsigned char *src[];
{
   unsigned char *lum=src[0];
   unsigned char *cb =src[1];
   unsigned char *cr =src[2];
   int            cols=coded_picture_width;
   int            rows=coded_picture_height;
   int            L, CR, CB;
   unsigned char *lum2, *r1, *r2;
   int            x, y;
   int            cr_r;
   int            cr_g;
   int            cb_g;
   int            cb_b;

#ifdef _WIN32
   r1 = dithered_image + (rows - 1) * cols * 3;
   r2 = r1 - cols * 3;
#else
   r1 = dithered_image;
   r2 = r1 + cols * 3;
#endif

   lum2 = lum + cols;
   for (y=0; y<rows; y+=2)
   {
      for (x=0; x<cols; x+=2)
      {
         int R, G, B;

         CR = *cr++;
         CB = *cb++;
         cr_r = Cr_r_tab[CR];
         cr_g = Cr_g_tab[CR];
         cb_g = Cb_g_tab[CB];
         cb_b = Cb_b_tab[CB];

         L = *lum++;
         L = Cy_tab[L];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r1++ = CLAMP(0,B,UP(255)) >> BITS;
         *r1++ = CLAMP(0,G,UP(255)) >> BITS;
         *r1++ = CLAMP(0,R,UP(255)) >> BITS;

         L = *lum++;
         L = Cy_tab[L];
         if (chroma_format==CHROMA444)
         {
            CR = *cr;
            CB = *cb;
            cr_r = Cr_r_tab[CR];
            cr_g = Cr_g_tab[CR];
            cb_g = Cb_g_tab[CB];
            cb_b = Cb_b_tab[CB];
         }
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r1++ = CLAMP(0,B,UP(255)) >> BITS;
         *r1++ = CLAMP(0,G,UP(255)) >> BITS;
         *r1++ = CLAMP(0,R,UP(255)) >> BITS;

         /*
          * Now, do second row.
          */
         if (chroma_format!=CHROMA420)
         {
            CR = cr[chrom_width-1];
            CB = cb[chrom_width-1];
            cr_r = Cr_r_tab[CR];
            cr_g = Cr_g_tab[CR];
            cb_g = Cb_g_tab[CB];
            cb_b = Cb_b_tab[CB];
         }
         L = *lum2++;
         L = Cy_tab[L];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r2++ = CLAMP(0,B,UP(255)) >> BITS;
         *r2++ = CLAMP(0,G,UP(255)) >> BITS;
         *r2++ = CLAMP(0,R,UP(255)) >> BITS;

         L = *lum2++;
         L = Cy_tab[L];
         if (chroma_format==CHROMA444)
         {
            CR = cr[chrom_width];
            CB = cb[chrom_width];
            cr_r = Cr_r_tab[CR];
            cr_g = Cr_g_tab[CR];
            cb_g = Cb_g_tab[CB];
            cb_b = Cb_b_tab[CB];
            cr++;
            cb++;
         }
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r2++ = CLAMP(0,B,UP(255)) >> BITS;
         *r2++ = CLAMP(0,G,UP(255)) >> BITS;
         *r2++ = CLAMP(0,R,UP(255)) >> BITS;
      }
      lum += cols;
      lum2 += cols;
      if (chroma_format!=CHROMA420)
      {
         cr += chrom_width;
         cb += chrom_width;
      }
#ifdef _WIN32
      r1 -= 9 * cols;
      r2 -= 9 * cols;
#else
      r1 += 3 * cols;
      r2 += 3 * cols;
#endif
   }
}

static void dithertopRGB(src,dst)
unsigned char *src[];
unsigned char *dst;
{
   unsigned char *lum=src[0];
   unsigned char *cb =src[1];
   unsigned char *cr =src[2];
   int            cols=coded_picture_width;
   int            rows=coded_picture_height;
   int            L, CR, CB;
   unsigned char *lum2, *r1, *r2;
   int            x, y;
   int            cr_r;
   int            cr_g;
   int            cb_g;
   int            cb_b;
   int            chrom_offset[3];

   if (chroma_format==CHROMA420)
      chrom_offset[0] = -chrom_width;
   else
      chrom_offset[0] =  chrom_width;
   chrom_offset[2] =  chrom_width;

#ifdef _WIN32
   r1 = dst + (rows - 1) * cols * 3;
   r2 = r1 - cols * 3;
#else
   r1 = dst;
   r2 = r1 + cols * 3;
#endif

   lum2 = lum + 2*cols;
   for (y=0; y<rows; y+=2)
   {
      for (x=0; x<cols; x+=2)
      {
         int R, G, B, Y;

         CR = *cr++;
         CB = *cb++;
         cr_r = Cr_r_tab[CR];
         cr_g = Cr_g_tab[CR];
         cb_g = Cb_g_tab[CB];
         cb_b = Cb_b_tab[CB];

         Y = *lum++;
         L = Cy_tab[Y];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r1++ = CLAMP(0,B,UP(255)) >> BITS;
         *r1++ = CLAMP(0,G,UP(255)) >> BITS;
         *r1++ = CLAMP(0,R,UP(255)) >> BITS;

         L = (Y + *lum2++)>>1;
         L = Cy_tab[L];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r2++ = CLAMP(0,B,UP(255)) >> BITS;
         *r2++ = CLAMP(0,G,UP(255)) >> BITS;
         *r2++ = CLAMP(0,R,UP(255)) >> BITS;

         Y = *lum++;
         L = Cy_tab[Y];
         if (chroma_format==CHROMA444)
         {
            CR = *cr++;
            CB = *cb++;
            cr_r = Cr_r_tab[CR];
            cr_g = Cr_g_tab[CR];
            cb_g = Cb_g_tab[CB];
            cb_b = Cb_b_tab[CB];
         }
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r1++ = CLAMP(0,B,UP(255)) >> BITS;
         *r1++ = CLAMP(0,G,UP(255)) >> BITS;
         *r1++ = CLAMP(0,R,UP(255)) >> BITS;

         L = (Y + *lum2++)>>1;
         L = Cy_tab[L];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r2++ = CLAMP(0,B,UP(255)) >> BITS;
         *r2++ = CLAMP(0,G,UP(255)) >> BITS;
         *r2++ = CLAMP(0,R,UP(255)) >> BITS;
      }
      lum += cols;
      if (y!=(rows-2))
        lum2 += cols;
      else
        lum2 -= cols;
      cb += chrom_offset[y & 2];
      cr += chrom_offset[y & 2];
#ifdef _WIN32
      r1 -= 9 * cols;
      r2 -= 9 * cols;
#else
      r1 += 3 * cols;
      r2 += 3 * cols;
#endif
   }
}

static void ditherbotRGB(src,dst)
unsigned char *src[];
unsigned char *dst;
{
   unsigned char *lum=src[0];
   unsigned char *cb =src[1] + chrom_width;
   unsigned char *cr =src[2] + chrom_width;
   int            cols=coded_picture_width;
   int            rows=coded_picture_height;
   int            L, CR, CB;
   unsigned char *lum2, *r1, *r2;
   int            x, y;
   int            cr_r;
   int            cr_g;
   int            cb_g;
   int            cb_b;
   int            chrom_offset[3];

   if (chroma_format==CHROMA420)
      chrom_offset[0] = -chrom_width;
   else
      chrom_offset[0] =  chrom_width;
   chrom_offset[2] =  chrom_width;

#ifdef _WIN32
   r1 = dst + (rows - 1) * cols * 3;
   r2 = r1 - cols * 3;
#else
   r1 = dst;
   r2 = r1 + cols * 3;
#endif

   lum +=cols;
   lum2 =lum;
   for (y=0; y<rows; y+=2)
   {
      for (x=0; x<cols; x+=2)
      {
         int R, G, B, Y;

         CR = *cr++;
         CB = *cb++;
         cr_r = Cr_r_tab[CR];
         cr_g = Cr_g_tab[CR];
         cb_g = Cb_g_tab[CB];
         cb_b = Cb_b_tab[CB];

         Y = *lum++;
         L = Cy_tab[Y];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r1++ = CLAMP(0,B,UP(255)) >> BITS;
         *r1++ = CLAMP(0,G,UP(255)) >> BITS;
         *r1++ = CLAMP(0,R,UP(255)) >> BITS;

         L = (Y + *lum2++)>>1;
         L = Cy_tab[L];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r2++ = CLAMP(0,B,UP(255)) >> BITS;
         *r2++ = CLAMP(0,G,UP(255)) >> BITS;
         *r2++ = CLAMP(0,R,UP(255)) >> BITS;

         Y = *lum++;
         L = Cy_tab[Y];
         if (chroma_format==CHROMA444)
         {
            CR = *cr++;
            CB = *cb++;
            cr_r = Cr_r_tab[CR];
            cr_g = Cr_g_tab[CR];
            cb_g = Cb_g_tab[CB];
            cb_b = Cb_b_tab[CB];
         }
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r1++ = CLAMP(0,B,UP(255)) >> BITS;
         *r1++ = CLAMP(0,G,UP(255)) >> BITS;
         *r1++ = CLAMP(0,R,UP(255)) >> BITS;

         L = (Y + *lum2++)>>1;
         L = Cy_tab[L];
         R = L + cr_r;
         G = L + cr_g + cb_g;
         B = L + cb_b;

         *r2++ = CLAMP(0,B,UP(255)) >> BITS;
         *r2++ = CLAMP(0,G,UP(255)) >> BITS;
         *r2++ = CLAMP(0,R,UP(255)) >> BITS;
      }
      lum += cols;
      if (y!=0)
        lum2 += cols;
      else
        lum2 -= cols;
      cb += chrom_offset[y & 2];
      cr += chrom_offset[y & 2];
#ifdef _WIN32
      r1 -= 9 * cols;
      r2 -= 9 * cols;
#else
      r1 += 3 * cols;
      r2 += 3 * cols;
#endif
   }
}


//
// portable display function
//
void display_second_field()
{
  display_image(dithered_image2);
}

#endif // DISPLAY