decoders.c

来自「mpeng Lib」· C语言 代码 · 共 936 行 · 第 1/3 页

0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
0x0011, 0x0011, 0x0011, 0x0011, 
};

unsigned short int dct_coeff_first[256] = 
{
0xffff, 0xffff, 0xffff, 0xffff, 
0xf7d5, 0xf7d5, 0xf7d5, 0xf7d5, 
0x0826, 0x0826, 0x2416, 0x2416, 
0x0046, 0x0046, 0x2016, 0x2016, 
0x1c15, 0x1c15, 0x1c15, 0x1c15, 
0x1815, 0x1815, 0x1815, 0x1815, 
0x0425, 0x0425, 0x0425, 0x0425, 
0x1415, 0x1415, 0x1415, 0x1415, 
0x3417, 0x0067, 0x3017, 0x2c17, 
0x0c27, 0x0437, 0x0057, 0x2817, 
0x0034, 0x0034, 0x0034, 0x0034, 
0x0034, 0x0034, 0x0034, 0x0034, 
0x1014, 0x1014, 0x1014, 0x1014, 
0x1014, 0x1014, 0x1014, 0x1014, 
0x0c14, 0x0c14, 0x0c14, 0x0c14, 
0x0c14, 0x0c14, 0x0c14, 0x0c14, 
0x0023, 0x0023, 0x0023, 0x0023, 
0x0023, 0x0023, 0x0023, 0x0023, 
0x0023, 0x0023, 0x0023, 0x0023, 
0x0023, 0x0023, 0x0023, 0x0023, 
0x0813, 0x0813, 0x0813, 0x0813, 
0x0813, 0x0813, 0x0813, 0x0813, 
0x0813, 0x0813, 0x0813, 0x0813, 
0x0813, 0x0813, 0x0813, 0x0813, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0412, 0x0412, 0x0412, 0x0412, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
0x0010, 0x0010, 0x0010, 0x0010, 
};

/* Macro for filling up the decoding table for mb_addr_inc */
#define ASSIGN1(start, end, step, val, num) \
  for (i = start; i < end; i+= step) { \
    for (j = 0; j < step; j++) { \
      mb_addr_inc[i+j].value = val; \
      mb_addr_inc[i+j].num_bits = num; \
    } \
    val--; \
    }



/*
 *--------------------------------------------------------------
 *
 * init_mb_addr_inc --
 *
 *	Initialize the VLC decoding table for macro_block_address_increment
 *
 * Results:
 *	The decoding table for macro_block_address_increment will
 *      be filled; illegal values will be filled as ERROR.
 *
 * Side effects:
 *	The global array mb_addr_inc will be filled.
 *
 *--------------------------------------------------------------
 */
static void
init_mb_addr_inc(void)
{
  int i, j, val;

  for (i = 0; i < 8; i++) {
    mb_addr_inc[i].value = ERROR;
    mb_addr_inc[i].num_bits = 0;
  }

  mb_addr_inc[8].value = MACRO_BLOCK_ESCAPE;
  mb_addr_inc[8].num_bits = 11;

  for (i = 9; i < 15; i++) {
    mb_addr_inc[i].value = ERROR;
    mb_addr_inc[i].num_bits = 0;
  }

  mb_addr_inc[15].value = MACRO_BLOCK_STUFFING;
  mb_addr_inc[15].num_bits = 11;

  for (i = 16; i < 24; i++) {
    mb_addr_inc[i].value = ERROR;
    mb_addr_inc[i].num_bits = 0;
  }

  val = 33;

  ASSIGN1(24, 36, 1, val, 11);
  ASSIGN1(36, 48, 2, val, 10);
  ASSIGN1(48, 96, 8, val, 8);
  ASSIGN1(96, 128, 16, val, 7);
  ASSIGN1(128, 256, 64, val, 5);
  ASSIGN1(256, 512, 128, val, 4);
  ASSIGN1(512, 1024, 256, val, 3);
  ASSIGN1(1024, 2048, 1024, val, 1);
}


/* Macro for filling up the decoding table for mb_type */
#define ASSIGN2(start, end, quant, motion_forward, motion_backward, pattern, intra, num, mb_type) \
  for (i = start; i < end; i ++) { \
    mb_type[i].mb_quant = quant; \
    mb_type[i].mb_motion_forward = motion_forward; \
    mb_type[i].mb_motion_backward = motion_backward; \
    mb_type[i].mb_pattern = pattern; \
    mb_type[i].mb_intra = intra; \
    mb_type[i].num_bits = num; \
  }
	 


/*
 *--------------------------------------------------------------
 *
 * init_mb_type_P --
 *
 *	Initialize the VLC decoding table for macro_block_type in
 *      predictive-coded pictures.
 *
 * Results:
 *	The decoding table for macro_block_type in predictive-coded
 *      pictures will be filled; illegal values will be filled as ERROR.
 *
 * Side effects:
 *	The global array mb_type_P will be filled.
 *
 *--------------------------------------------------------------
 */
static void
init_mb_type_P(void)
{
  int i;

  mb_type_P[0].mb_quant = mb_type_P[0].mb_motion_forward 
    = mb_type_P[0].mb_motion_backward = mb_type_P[0].mb_pattern 
      = mb_type_P[0].mb_intra = ERROR;
  mb_type_P[0].num_bits = 0;

  ASSIGN2(1, 2, 1, 0, 0, 0, 1, 6, mb_type_P)
  ASSIGN2(2, 4, 1, 0, 0, 1, 0, 5, mb_type_P)
  ASSIGN2(4, 6, 1, 1, 0, 1, 0, 5, mb_type_P);
  ASSIGN2(6, 8, 0, 0, 0, 0, 1, 5, mb_type_P);
  ASSIGN2(8, 16, 0, 1, 0, 0, 0, 3, mb_type_P);
  ASSIGN2(16, 32, 0, 0, 0, 1, 0, 2, mb_type_P);
  ASSIGN2(32, 64, 0, 1, 0, 1, 0, 1, mb_type_P);
}




/*
 *--------------------------------------------------------------
 *
 * init_mb_type_B --
 *
 *	Initialize the VLC decoding table for macro_block_type in
 *      bidirectionally-coded pictures.
 *
 * Results:
 *	The decoding table for macro_block_type in bidirectionally-coded
 *      pictures will be filled; illegal values will be filled as ERROR.
 *
 * Side effects:
 *	The global array mb_type_B will be filled.
 *
 *--------------------------------------------------------------
 */
static void
init_mb_type_B(void)
{
  int i;

  mb_type_B[0].mb_quant = mb_type_B[0].mb_motion_forward 
    = mb_type_B[0].mb_motion_backward = mb_type_B[0].mb_pattern 
      = mb_type_B[0].mb_intra = ERROR;
  mb_type_B[0].num_bits = 0;

  ASSIGN2(1, 2, 1, 0, 0, 0, 1, 6, mb_type_B);
  ASSIGN2(2, 3, 1, 0, 1, 1, 0, 6, mb_type_B);
  ASSIGN2(3, 4, 1, 1, 0, 1, 0, 6, mb_type_B);
  ASSIGN2(4, 6, 1, 1, 1, 1, 0, 5, mb_type_B);
  ASSIGN2(6, 8, 0, 0, 0, 0, 1, 5, mb_type_B);
  ASSIGN2(8, 12, 0, 1, 0, 0, 0, 4, mb_type_B);
  ASSIGN2(12, 16, 0, 1, 0, 1, 0, 4, mb_type_B);
  ASSIGN2(16, 24, 0, 0, 1, 0, 0, 3, mb_type_B);
  ASSIGN2(24, 32, 0, 0, 1, 1, 0, 3, mb_type_B);
  ASSIGN2(32, 48, 0, 1, 1, 0, 0, 2, mb_type_B);
  ASSIGN2(48, 64, 0, 1, 1, 1, 0, 2, mb_type_B);
}


/* Macro for filling up the decoding tables for motion_vectors */
#define ASSIGN3(start, end, step, val, num) \
  for (i = start; i < end; i+= step) { \
    for (j = 0; j < step / 2; j++) { \
      motion_vectors[i+j].code = val; \
      motion_vectors[i+j].num_bits = num; \
    } \
    for (j = step / 2; j < step; j++) { \
      motion_vectors[i+j].code = -val; \
      motion_vectors[i+j].num_bits = num; \
    } \
    val--; \
  }



/*
 *--------------------------------------------------------------
 *
 * init_motion_vectors --
 *
 *	Initialize the VLC decoding table for the various motion
 *      vectors, including motion_horizontal_forward_code, 
 *      motion_vertical_forward_code, motion_horizontal_backward_code,
 *      and motion_vertical_backward_code.
 *
 * Results:
 *	The decoding table for the motion vectors will be filled;
 *      illegal values will be filled as ERROR.
 *
 * Side effects:
 *	The global array motion_vector will be filled.
 *
 *--------------------------------------------------------------
 */
static void
init_motion_vectors(void)
{
  int i, j, val = 16;

  for (i = 0; i < 24; i++) {
    motion_vectors[i].code = ERROR;
    motion_vectors[i].num_bits = 0;
  }

  ASSIGN3(24, 36, 2, val, 11);
  ASSIGN3(36, 48, 4, val, 10);
  ASSIGN3(48, 96, 16, val, 8);
  ASSIGN3(96, 128, 32, val, 7);
  ASSIGN3(128, 256, 128, val, 5);
  ASSIGN3(256, 512, 256, val, 4);
  ASSIGN3(512, 1024, 512, val, 3);
  ASSIGN3(1024, 2048, 1024, val, 1);
}




/*
 *--------------------------------------------------------------
 *
 * init_tables --
 *
 *	Initialize all the tables for VLC decoding; this must be
 *      called when the system is set up before any decoding can
 *      take place.