MPEG4格式解码源代码

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MPEG4格式解码源代码
【文件名】:06117@52RD_MPEG4格式解码源代码.zip
【格　式】:zip
【大　小】:144K
【简　介】:
【目　录】:



void initdecoder (DEC_BUFFERS buffers)
{
  int i, j, cc;
save_tables(mp4_tables);
  mp4_state->clp = mp4_state->clp_data + 384;
  for (i = -384; i < 640; i++)
    mp4_state->clp = (unsigned char) ( (i < 0) ? 0 : ((i > 255) ? 255 : i) );

/* dc prediction border */
for (i = 0; i < (2*DEC_MBC+1); i++)
  mp4_state->coeff_pred.dc_store_lum[0] = 1024;
for (i = 1; i < (2*DEC_MBR+1); i++)
  mp4_state->coeff_pred.dc_store_lum[0] = 1024;
for (i = 0; i < (DEC_MBC+1); i++) {
  mp4_state->coeff_pred.dc_store_chr[0][0] = 1024;
  mp4_state->coeff_pred.dc_store_chr[1][0] = 1024;
}
for (i = 1; i < (DEC_MBR+1); i++) {
  mp4_state->coeff_pred.dc_store_chr[0][0] = 1024;
  mp4_state->coeff_pred.dc_store_chr[1][0] = 1024;
}
/* ac prediction border */
for (i = 0; i < (2*DEC_MBC+1); i++)
  for (j = 0; j < 7; j++) {
   mp4_state->coeff_pred.ac_left_lum[0][j] = 0;
   mp4_state->coeff_pred.ac_top_lum[0][j] = 0;
  }
for (i = 1; i < (2*DEC_MBR+1); i++)
  for (j = 0; j < 7; j++) {
   mp4_state->coeff_pred.ac_left_lum[0][j] = 0;
   mp4_state->coeff_pred.ac_top_lum[0][j] = 0;
  }
/*
   [Review] too many computation to access to the
   correct array value, better use two different
   pointer for Cb and Cr components
*/
for (i = 0; i < (DEC_MBC+1); i++)
  for (j = 0; j < 7; j++) {
   mp4_state->coeff_pred.ac_left_chr[0][0][j] = 0;
   mp4_state->coeff_pred.ac_top_chr[0][0][j] = 0;
   mp4_state->coeff_pred.ac_left_chr[1][0][j] = 0;
   mp4_state->coeff_pred.ac_top_chr[1][0][j] = 0;
  }
for (i = 1; i < (DEC_MBR+1); i++)
  for (j = 0; j < 7; j++) {
   mp4_state->coeff_pred.ac_left_chr[0][0][j] = 0;
   mp4_state->coeff_pred.ac_top_chr[0][0][j] = 0;
   mp4_state->coeff_pred.ac_left_chr[1][0][j] = 0;
   mp4_state->coeff_pred.ac_top_chr[1][0][j] = 0;
  }

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