display.c

该源码可以将mpeg、mpg和m2v格式的视频文件解码成yuv、ppm、tga等格式文件

      y2 = *py2++;
      u = *pu++ >> 1;
      v = *pv++ >> 1;
      *dst++  = pixel[ytab[((y+y2)>>1)]|utab[u]|vtab[v]];
      *dst2++ = pixel[ytab[y2+12]|utab[u+12]|vtab[v+12]];

      y = *py++;
      y2 = *py2++;
      if (chroma_format==CHROMA444)
      {
        u = *pu++ >> 1;
        v = *pv++ >> 1;
      }
      *dst++  = pixel[ytab[((y+y2)>>1)+8]|utab[u+8]|vtab[v+8]];
      *dst2++ = pixel[ytab[y2+4]|utab[u+4]|vtab[v+4]];

      y = *py++;
      y2 = *py2++;
      u = *pu++ >> 1;
      v = *pv++ >> 1;
      *dst++  = pixel[ytab[((y+y2)>>1)+2]|utab[u+2]|vtab[v+2]];
      *dst2++ = pixel[ytab[y2+14]|utab[u+14]|vtab[v+14]];

      y = *py++;
      y2 = *py2++;
      if (chroma_format==CHROMA444)
      {
        u = *pu++ >> 1;
        v = *pv++ >> 1;
      }
      *dst++  = pixel[ytab[((y+y2)>>1)+10]|utab[u+10]|vtab[v+10]];
      *dst2++ = pixel[ytab[y2+6]|utab[u+6]|vtab[v+6]];
    }

    if (j==0)
      py -= coded_picture_width;
    else
      py += coded_picture_width;

    py2 += coded_picture_width;
    dst += coded_picture_width;
    dst2 += coded_picture_width;

    if (chroma_format==CHROMA420)
    {
      pu -= chrom_width;
      pv -= chrom_width;
    }
    else
    {
      pu += chrom_width;
      pv += chrom_width;
    }

    /* line j + 2. j + 3 */
    for (i=0; i<coded_picture_width; i+=4)
    {
      y = *py++;
      y2 = *py2++;
      u = *pu++ >> 1;
      v = *pv++ >> 1;
      *dst++  = pixel[ytab[((y+y2)>>1)+3]|utab[u+3]|vtab[v+3]];
      *dst2++ = pixel[ytab[y2+15]|utab[u+15]|vtab[v+15]];

      y = *py++;
      y2 = *py2++;
      if (chroma_format==CHROMA444)
      {
        u = *pu++ >> 1;
        v = *pv++ >> 1;
      }
      *dst++  = pixel[ytab[((y+y2)>>1)+11]|utab[u+11]|vtab[v+11]];
      *dst2++ = pixel[ytab[y2+7]|utab[u+7]|vtab[v+7]];

      y = *py++;
      y2 = *py2++;
      u = *pu++ >> 1;
      v = *pv++ >> 1;
      *dst++  = pixel[ytab[((y+y2)>>1)+1]|utab[u+1]|vtab[v+1]];
      *dst2++ = pixel[ytab[y2+13]|utab[u+13]|vtab[v+13]];

      y = *py++;
      y2 = *py2++;
      if (chroma_format==CHROMA444)
      {
        u = *pu++ >> 1;
        v = *pv++ >> 1;
      }
      *dst++  = pixel[ytab[((y+y2)>>1)+9]|utab[u+9]|vtab[v+9]];
      *dst2++ = pixel[ytab[y2+5]|utab[u+5]|vtab[v+5]];
    }

    py += coded_picture_width;
    py2 += coded_picture_width;
    dst += coded_picture_width;
    dst2 += coded_picture_width;
    pu += chrom_width;
    pv += chrom_width;
  }
}

static void dithertop420(src,dst)
unsigned char *src[];
unsigned char *dst;
{
  int i,j;
  int y1,u1,v1,y2,u2,v2;
  unsigned char *py1,*pu1,*pv1,*py2,*pu2,*pv2,*dst2;

  py1 = src[0];
  pu1 = src[1];
  pv1 = src[2];

  py2 = py1 + (coded_picture_width<<1);
  pu2 = pu1 + (chrom_width<<1);
  pv2 = pv1 + (chrom_width<<1);

  dst2 = dst + coded_picture_width;

  for (j=0; j<coded_picture_height; j+=4)
  {
    /* line j + 0, j + 1 */
    for (i=0; i<coded_picture_width; i+=4)
    {
      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)]|utab[u1]|vtab[v1]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+12]|utab[((3*u1+u2)>>2)+12]
                                             |vtab[((3*v1+v2)>>2)+12]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+8]|utab[u1+8]|vtab[v1+8]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+4]|utab[((3*u1+u2)>>2)+4]
                                            |vtab[((3*v1+v2)>>2)+4]];

      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+2]|utab[u1+2]|vtab[v1+2]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+14]|utab[((3*u1+u2)>>2)+14]
                                             |vtab[((3*v1+v2)>>2)+14]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+10]|utab[u1+10]|vtab[v1+10]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+6]|utab[((3*u1+u2)>>2)+6]
                                            |vtab[((3*v1+v2)>>2)+6]];
    }

    py1 += coded_picture_width;

    if (j!=(coded_picture_height-4))
      py2 += coded_picture_width;
    else
      py2 -= coded_picture_width;

    pu1 -= chrom_width;
    pv1 -= chrom_width;
    pu2 -= chrom_width;
    pv2 -= chrom_width;

    dst  += coded_picture_width;
    dst2 += coded_picture_width;

    /* line j + 2, j + 3 */
    for (i=0; i<coded_picture_width; i+=4)
    {
      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+3]|utab[((u1+u2)>>1)+3]
                                            |vtab[((v1+v2)>>1)+3]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+15]|utab[((u1+3*u2)>>2)+15]
                                             |vtab[((v1+3*v2)>>2)+15]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+11]|utab[((u1+u2)>>1)+11]
                                             |vtab[((v1+v2)>>1)+11]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+7]|utab[((u1+3*u2)>>2)+7]
                                            |vtab[((v1+3*v2)>>2)+7]];

      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+1]|utab[((u1+u2)>>1)+1]
                                            |vtab[((v1+v2)>>1)+1]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+13]|utab[((u1+3*u2)>>2)+13]
                                             |vtab[((v1+3*v2)>>2)+13]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+9]|utab[((u1+u2)>>1)+9]
                                            |vtab[((v1+v2)>>1)+9]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+5]|utab[((u1+3*u2)>>2)+5]
                                            |vtab[((v1+3*v2)>>2)+5]];
    }

    py1 += coded_picture_width;
    py2 += coded_picture_width;
    pu1 += chrom_width;
    pv1 += chrom_width;
    if (j!=(coded_picture_height-8))
    {
      pu2 += chrom_width;
      pv2 += chrom_width;
    }
    else
    {
      pu2 -= chrom_width;
      pv2 -= chrom_width;
    }
    dst += coded_picture_width;
    dst2+= coded_picture_width;
  }
}

static void ditherbot420(src,dst)
unsigned char *src[];
unsigned char *dst;
{
  int i,j;
  int y1,u1,v1,y2,u2,v2;
  unsigned char *py1,*pu1,*pv1,*py2,*pu2,*pv2,*dst2;

  py2 = py1 = src[0] + coded_picture_width;
  pu2 = pu1 = src[1] + chrom_width;
  pv2 = pv1 = src[2] + chrom_width;

  dst2 = dst;

  for (j=0; j<coded_picture_height; j+=4)
  {
    /* line j + 0, j + 1 */
    for (i=0; i<coded_picture_width; i+=4)
    {
      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+15]|utab[((3*u1+u2)>>2)+15]
                                             |vtab[((3*v1+v2)>>2)+15]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)]|utab[((u1+u2)>>1)]
                                          |vtab[((v1+v2)>>1)]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+7]|utab[((3*u1+u2)>>2)+7]
                                            |vtab[((3*v1+v2)>>2)+7]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+8]|utab[((u1+u2)>>1)+8]
                                            |vtab[((v1+v2)>>1)+8]];

      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+13]|utab[((3*u1+u2)>>2)+13]
                                             |vtab[((3*v1+v2)>>2)+13]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+2]|utab[((u1+u2)>>1)+2]
                                            |vtab[((v1+v2)>>1)+2]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+5]|utab[((3*u1+u2)>>2)+5]
                                            |vtab[((3*v1+v2)>>2)+5]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+10]|utab[((u1+u2)>>1)+10]
                                             |vtab[((v1+v2)>>1)+10]];
    }

    if (j!=0)
      py1 += coded_picture_width;
    else
      py1 -= coded_picture_width;

    py2 += coded_picture_width;

    pu1 -= chrom_width;
    pv1 -= chrom_width;
    pu2 -= chrom_width;
    pv2 -= chrom_width;

    if (j!=0)
      dst  += coded_picture_width;

    dst2 += coded_picture_width;

    /* line j + 2, j + 3 */
    for (i=0; i<coded_picture_width; i+=4)
    {
      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+12]|utab[((u1+3*u2)>>2)+12]
                                             |vtab[((v1+3*v2)>>2)+12]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+3]|utab[u2+3]
                                            |vtab[v2+3]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+4]|utab[((u1+3*u2)>>2)+4]
                                            |vtab[((v1+3*v2)>>2)+4]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+11]|utab[u2+11]
                                             |vtab[v2+11]];

      y1 = *py1++;
      y2 = *py2++;
      u1 = *pu1++ >> 1;
      v1 = *pv1++ >> 1;
      u2 = *pu2++ >> 1;
      v2 = *pv2++ >> 1;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+14]|utab[((u1+3*u2)>>2)+14]
                                             |vtab[((v1+3*v2)>>2)+14]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+1]|utab[u2+1]
                                            |vtab[v2+1]];

      y1 = *py1++;
      y2 = *py2++;
      *dst++  = pixel[ytab[((3*y1+y2)>>2)+6]|utab[((u1+3*u2)>>2)+6]
                                            |vtab[((v1+3*v2)>>2)+6]];
      *dst2++ = pixel[ytab[((y1+3*y2)>>2)+9]|utab[u2+9]
                                            |vtab[v2+9]];
    }

    py1 += coded_picture_width;
    py2 += coded_picture_width;

    if (j!=0)
    {
      pu1 += chrom_width;
      pv1 += chrom_width;
    }
    else
    {
      pu1 -= chrom_width;
      pv1 -= chrom_width;
    }

    pu2 += chrom_width;
    pv2 += chrom_width;

    dst += coded_picture_width;
    dst2+= coded_picture_width;
  }

  py2 -= (coded_picture_width<<1);
  pu2 -= (chrom_width<<1);
  pv2 -= (chrom_width<<1);

  /* dither last line */
  for (i=0; i<coded_picture_width; i+=4)
  {
    y1 = *py1++;
    y2 = *py2++;
    u1 = *pu1++ >> 1;
    v1 = *pv1++ >> 1;
    u2 = *pu2++ >> 1;
    v2 = *pv2++ >> 1;
    *dst++  = pixel[ytab[((3*y1+y2)>>2)+15]|utab[((3*u1+u2)>>2)+15]
                                           |vtab[((3*v1+v2)>>2)+15]];

    y1 = *py1++;
    y2 = *py2++;
    *dst++  = pixel[ytab[((3*y1+y2)>>2)+7]|utab[((3*u1+u2)>>2)+7]
                                          |vtab[((3*v1+v2)>>2)+7]];

    y1 = *py1++;
    y2 = *py2++;
    u1 = *pu1++ >> 1;
    v1 = *pv1++ >> 1;
    u2 = *pu2++ >> 1;
    v2 = *pv2++ >> 1;
    *dst++  = pixel[ytab[((3*y1+y2)>>2)+13]|utab[((3*u1+u2)>>2)+13]
                                           |vtab[((3*v1+v2)>>2)+13]];

    y1 = *py1++;
    y2 = *py2++;
    *dst++  = pixel[ytab[((3*y1+y2)>>2)+5]|utab[((3*u1+u2)>>2)+5]
                                          |vtab[((3*v1+v2)>>2)+5]];
    }

}
#endif