jpegutils.c

来自「Motion JPEG编解码器源代码」· C语言 代码 · 共 1,145 行 · 第 1/3 页

      0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
      0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
      0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
      0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
      0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
      0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
      0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
      0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
      0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
      0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
      0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
      0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
      0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
      0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
      0xf9, 0xfa };
  
  add_huff_table(dinfo, &dinfo->dc_huff_tbl_ptrs[0],
		 bits_dc_luminance, val_dc_luminance);
  add_huff_table(dinfo, &dinfo->ac_huff_tbl_ptrs[0],
		 bits_ac_luminance, val_ac_luminance);
  add_huff_table(dinfo, &dinfo->dc_huff_tbl_ptrs[1],
		 bits_dc_chrominance, val_dc_chrominance);
  add_huff_table(dinfo, &dinfo->ac_huff_tbl_ptrs[1],
		 bits_ac_chrominance, val_ac_chrominance);
}



static void guarantee_huff_tables(j_decompress_ptr dinfo)
{
  if ( (dinfo->dc_huff_tbl_ptrs[0] == NULL) &&
       (dinfo->dc_huff_tbl_ptrs[1] == NULL) &&
       (dinfo->ac_huff_tbl_ptrs[0] == NULL) &&
       (dinfo->ac_huff_tbl_ptrs[1] == NULL) ) {
    mjpeg_debug( "Generating standard Huffman tables for this frame.");
    std_huff_tables(dinfo);
  }
}


#endif /* ...'std' Huffman table generation */



/*
 * jpeg_data:       Buffer with jpeg data to decode
 * len:             Length of buffer
 * itype:           0: Not interlaced
 *                  1: Interlaced, Top field first
 *                  2: Interlaced, Bottom field first
 * ctype            Chroma format for decompression.
 *                  Currently only CHROMA420 and CHROMA422 are available
 */

int decode_jpeg_raw (unsigned char *jpeg_data, int len,
                     int itype, int ctype, int width, int height,
                     unsigned char *raw0, unsigned char *raw1,
                     unsigned char *raw2)
{
   int numfields, hsf[3], vsf[3], field, yl, yc, x, y = 0, i, xsl, xsc, xs, xd,
       hdown;

   JSAMPROW row0[16] = { buf0[0], buf0[1], buf0[2], buf0[3],
      buf0[4], buf0[5], buf0[6], buf0[7],
      buf0[8], buf0[9], buf0[10], buf0[11],
      buf0[12], buf0[13], buf0[14], buf0[15]
   };
   JSAMPROW row1[8] = { buf1[0], buf1[1], buf1[2], buf1[3],
			buf1[4], buf1[5], buf1[6], buf1[7]   };
   JSAMPROW row2[16] = { buf2[0], buf2[1], buf2[2], buf2[3],
			 buf2[4], buf2[5], buf2[6], buf2[7]  };
   JSAMPROW row1_444[16], row2_444[16];
   JSAMPARRAY scanarray[3] = { row0, row1, row2 };
   struct jpeg_decompress_struct dinfo;
   struct my_error_mgr jerr;

   /* We set up the normal JPEG error routines, then override error_exit. */
   dinfo.err = jpeg_std_error (&jerr.pub);
   jerr.pub.error_exit = my_error_exit;

   /* Establish the setjmp return context for my_error_exit to use. */
   if (setjmp (jerr.setjmp_buffer)) {
      /* If we get here, the JPEG code has signaled an error. */
      jpeg_destroy_decompress (&dinfo);
      return -1;
   }

   jpeg_create_decompress (&dinfo);

   jpeg_buffer_src (&dinfo, jpeg_data, len);

   /* Read header, make some checks and try to figure out what the
      user really wants */

   jpeg_read_header (&dinfo, TRUE);
   dinfo.raw_data_out = TRUE;
   dinfo.out_color_space = JCS_YCbCr;
   dinfo.dct_method = JDCT_IFAST;
   guarantee_huff_tables(&dinfo);
   jpeg_start_decompress (&dinfo);

   if (dinfo.output_components != 3) {
      mjpeg_error( "Output components of JPEG image = %d, must be 3",
               dinfo.output_components);
      goto ERR_EXIT;
   }

   for (i = 0; i < 3; i++) {
      hsf[i] = dinfo.comp_info[i].h_samp_factor;
      vsf[i] = dinfo.comp_info[i].v_samp_factor;
   }

   //mjpeg_info( "Sampling factors, hsf=(%d, %d, %d) vsf=(%d, %d, %d) !", hsf[0], hsf[1], hsf[2], vsf[0], vsf[1], vsf[2]);
   if ((hsf[0] != 2 && hsf[0] != 1) || hsf[1] != 1 || hsf[2] != 1 ||
       (vsf[0] != 1 && vsf[0] != 2) || vsf[1] != 1 || vsf[2] != 1) {
      mjpeg_error( "Unsupported sampling factors, hsf=(%d, %d, %d) vsf=(%d, %d, %d) !", hsf[0], hsf[1], hsf[2], vsf[0], vsf[1], vsf[2]);
      goto ERR_EXIT;
   }

   if (hsf[0] == 1)
     {
       if (height % 8 != 0)
	 {
	   mjpeg_error( "YUV 4:4:4 sampling, but image height %d not dividable by 8 !\n", height);
	   goto ERR_EXIT;	   
	 }

       mjpeg_info("YUV 4:4:4 sampling encountered ! Allocating special row buffer\n");
       for (y = 0; y < 16; y++) // allocate a special buffer for the extra sampling depth
	 {
	   //mjpeg_info("YUV 4:4:4 %d.\n",y);
	   row1_444[y] = (unsigned char *)malloc(dinfo.output_width * sizeof(char));
	   row2_444[y] = (unsigned char *)malloc(dinfo.output_width * sizeof(char));
	 }
       //mjpeg_info("YUV 4:4:4 sampling encountered ! Allocating done.\n");
       scanarray[1] = row1_444; 
       scanarray[2] = row2_444; 
     }

   /* Height match image height or be exact twice the image height */

   if (dinfo.output_height == height) {
      numfields = 1;
   } else if (2 * dinfo.output_height == height) {
      numfields = 2;
   } else {
      mjpeg_error(
               "Read JPEG: requested height = %d, height of image = %d",
               height, dinfo.output_height);
      goto ERR_EXIT;
   }

   /* Width is more flexible */

   if (dinfo.output_width > MAX_LUMA_WIDTH) {
      mjpeg_error( "Image width of %d exceeds max",
               dinfo.output_width);
      goto ERR_EXIT;
   }
   if (width < 2 * dinfo.output_width / 3) {
      /* Downsample 2:1 */

      hdown = 1;
      if (2 * width < dinfo.output_width)
         xsl = (dinfo.output_width - 2 * width) / 2;
      else
         xsl = 0;
   } else if (width == 2 * dinfo.output_width / 3) {
      /* special case of 3:2 downsampling */

      hdown = 2;
      xsl = 0;
   } else {
      /* No downsampling */

      hdown = 0;
      if (width < dinfo.output_width)
         xsl = (dinfo.output_width - width) / 2;
      else
         xsl = 0;
   }

   /* Make xsl even, calculate xsc */

   xsl = xsl & ~1;
   xsc = xsl / 2;

   yl = yc = 0;

   for (field = 0; field < numfields; field++) {
      if (field > 0) {
         jpeg_read_header (&dinfo, TRUE);
         dinfo.raw_data_out = TRUE;
         dinfo.out_color_space = JCS_YCbCr;
         dinfo.dct_method = JDCT_IFAST;
         jpeg_start_decompress (&dinfo);
      }

      if (numfields == 2) {
         switch (itype) {
         case LAV_INTER_TOP_FIRST:
            yl = yc = field;
            break;
         case LAV_INTER_BOTTOM_FIRST:
            yl = yc = (1 - field);
            break;
         default:
            mjpeg_error(
                     "Input is interlaced but no interlacing set");
            goto ERR_EXIT;
         }
      } else
         yl = yc = 0;

      while (dinfo.output_scanline < dinfo.output_height) {
	/* read raw data */
	jpeg_read_raw_data (&dinfo, scanarray, 8 * vsf[0]);

         for (y = 0; y < 8 * vsf[0]; yl += numfields, y++) {
            xd = yl * width;
            xs = xsl;

            if (hdown == 0)
               for (x = 0; x < width; x++)
                  raw0[xd++] = row0[y][xs++];
            else if (hdown == 1)
               for (x = 0; x < width; x++, xs += 2)
                  raw0[xd++] = (row0[y][xs] + row0[y][xs + 1]) >> 1;
            else
               for (x = 0; x < width / 2; x++, xd += 2, xs += 3) {
                  raw0[xd] = (2 * row0[y][xs] + row0[y][xs + 1]) / 3;
                  raw0[xd + 1] =
                      (2 * row0[y][xs + 2] + row0[y][xs + 1]) / 3;
               }
         }

	 /* Horizontal downsampling of chroma */

         for (y = 0; y < 8; y++) {
            xs = xsc;

	    if (hsf[0] == 1)
	      for (x = 0; x < width / 2; x++, xs++) 
		{		  
		  row1[y][xs] = (row1_444[y][2*x] + row1_444[y][2*x + 1]) >> 1;
		  row2[y][xs] = (row2_444[y][2*x] + row2_444[y][2*x + 1]) >> 1;
		}

            xs = xsc;
            if (hdown == 0)
               for (x = 0; x < width / 2; x++, xs++) {
		 chr1[y][x] = row1[y][xs];
		 chr2[y][x] = row2[y][xs];
            } else if (hdown == 1)
               for (x = 0; x < width / 2; x++, xs += 2) {
                  chr1[y][x] = (row1[y][xs] + row1[y][xs + 1]) >> 1;
                  chr2[y][x] = (row2[y][xs] + row2[y][xs + 1]) >> 1;
            } else
               for (x = 0; x < width / 2; x += 2, xs += 3) {
                  chr1[y][x] = (2 * row1[y][xs] + row1[y][xs + 1]) / 3;
                  chr1[y][x + 1] =
                      (2 * row1[y][xs + 2] + row1[y][xs + 1]) / 3;
                  chr2[y][x] = (2 * row2[y][xs] + row2[y][xs + 1]) / 3;
                  chr2[y][x + 1] =
                      (2 * row2[y][xs + 2] + row2[y][xs + 1]) / 3;
               }
         }

	 /* Vertical resampling of chroma */

	 switch (ctype) {
	 case CHROMA422:
	   if (vsf[0] == 1) {
	     /* Just copy */
	     for (y = 0; y < 8 /*&& yc < height */; y++, yc += numfields) {
	       xd = yc * width / 2;
	       for (x = 0; x < width / 2; x++, xd++) {
		 raw1[xd] = chr1[y][x];
		 raw2[xd] = chr2[y][x];
	       }
	     }
	   } else {
	     /* upsample */
	     for (y = 0; y < 8 /*&& yc < height */; y++) {
	       xd = yc * width / 2;
	       for (x = 0; x < width / 2; x++, xd++) {
		 raw1[xd] = chr1[y][x];
		 raw2[xd] = chr2[y][x];
	       }
	       yc += numfields;
	       xd = yc * width / 2;
	       for (x = 0; x < width / 2; x++, xd++) {
		 raw1[xd] = chr1[y][x];
		 raw2[xd] = chr2[y][x];
	       }
	       yc += numfields;
	     }
	   }
	   break;
	 default:
	 /* should be case CHROMA420: but use default: for compatibility of liblavjpeg.so */
	   if (vsf[0] == 1) {
	     /* Really downsample */
	     for (y = 0; y < 8 /*&& yc < height/2*/; y += 2, yc += numfields) {
	       xd = yc * width / 2;
	       for (x = 0; x < width / 2; x++, xd++) {
		 assert(xd < (width * height / 4));
		 raw1[xd] = (chr1[y][x] + chr1[y + 1][x]) >> 1;
		 raw2[xd] = (chr2[y][x] + chr2[y + 1][x]) >> 1;
	       }
	     }

	   } else {
	     /* Just copy */
	     for (y = 0; y < 8 /*&& yc < height/2 */; y++, yc += numfields) {
	       xd = yc * width / 2;
	       for (x = 0; x < width / 2; x++, xd++) {
		 raw1[xd] = chr1[y][x];
		 raw2[xd] = chr2[y][x];
	       }
	     }
	   }
	   break;
	 }
      }

      (void) jpeg_finish_decompress (&dinfo);
      if (field == 0 && numfields > 1)
         jpeg_skip_ff (&dinfo);
   }

   if (hsf[0] == 1)
     {
       //mjpeg_info("YUV 4:4:4 sampling encountered ! Deallocating special row buffer\n");
       for (y = 0; y < 16; y++) // allocate a special buffer for the extra sampling depth
	 {
	   free(row1_444[y]);
	   free(row2_444[y]);
	 }
     }

   jpeg_destroy_decompress (&dinfo);
   return 0;

 ERR_EXIT:
   jpeg_destroy_decompress (&dinfo);
   return -1;
}

/*
 * jpeg_data:       Buffer with jpeg data to decode, must be grayscale mode
 * len:             Length of buffer
 * itype:           0: Not interlaced
 *                  1: Interlaced, Top field first
 *                  2: Interlaced, Bottom field first
 * ctype            Chroma format for decompression.
 *                  Currently only CHROMA420 and CHROMA422 are available
 */


int decode_jpeg_gray_raw (unsigned char *jpeg_data, int len,
			  int itype, int ctype, int width, int height,
			  unsigned char *raw0, unsigned char *raw1,
			  unsigned char *raw2)
{
   int numfields, hsf[3], vsf[3], field, yl, yc, x, y, xsl, xsc, xs, xd,
       hdown;

   JSAMPROW row0[16] = { buf0[0], buf0[1], buf0[2], buf0[3],
      buf0[4], buf0[5], buf0[6], buf0[7],
      buf0[8], buf0[9], buf0[10], buf0[11],
      buf0[12], buf0[13], buf0[14], buf0[15]
   };
   JSAMPARRAY scanarray[3] = { row0 };
   struct jpeg_decompress_struct dinfo;
   struct my_error_mgr jerr;

   mjpeg_info("decoding jpeg gray\n");

   /* We set up the normal JPEG error routines, then override error_exit. */
   dinfo.err = jpeg_std_error (&jerr.pub);
   jerr.pub.error_exit = my_error_exit;