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[/] [bluespec-h264/] [trunk/] [test/] [decoder/] [ldecod/] [src/] [biaridecod.c] - Rev 100
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/*! ************************************************************************************* * \file biaridecod.c * * \brief * binary arithmetic decoder routines * \date * 21. Oct 2000 * \author * Main contributors (see contributors.h for copyright, address and affiliation details) * - Detlev Marpe <marpe@hhi.de> * - Gabi Blaettermann <blaetter@hhi.de> ************************************************************************************* */ #include <stdlib.h> #include "global.h" #include "memalloc.h" extern int symbolCount; int binCount = 0; #define Dbuffer (dep->Dbuffer) #define Dbits_to_go (dep->Dbits_to_go) #define Dcodestrm (dep->Dcodestrm) #define Dcodestrm_len (dep->Dcodestrm_len) #define B_BITS 10 // Number of bits to represent the whole coding interval #define HALF (1 << (B_BITS-1)) #define QUARTER (1 << (B_BITS-2)) /* Range table for LPS */ const byte rLPS_table_64x4[64][4]= { { 128, 176, 208, 240}, { 128, 167, 197, 227}, { 128, 158, 187, 216}, { 123, 150, 178, 205}, { 116, 142, 169, 195}, { 111, 135, 160, 185}, { 105, 128, 152, 175}, { 100, 122, 144, 166}, { 95, 116, 137, 158}, { 90, 110, 130, 150}, { 85, 104, 123, 142}, { 81, 99, 117, 135}, { 77, 94, 111, 128}, { 73, 89, 105, 122}, { 69, 85, 100, 116}, { 66, 80, 95, 110}, { 62, 76, 90, 104}, { 59, 72, 86, 99}, { 56, 69, 81, 94}, { 53, 65, 77, 89}, { 51, 62, 73, 85}, { 48, 59, 69, 80}, { 46, 56, 66, 76}, { 43, 53, 63, 72}, { 41, 50, 59, 69}, { 39, 48, 56, 65}, { 37, 45, 54, 62}, { 35, 43, 51, 59}, { 33, 41, 48, 56}, { 32, 39, 46, 53}, { 30, 37, 43, 50}, { 29, 35, 41, 48}, { 27, 33, 39, 45}, { 26, 31, 37, 43}, { 24, 30, 35, 41}, { 23, 28, 33, 39}, { 22, 27, 32, 37}, { 21, 26, 30, 35}, { 20, 24, 29, 33}, { 19, 23, 27, 31}, { 18, 22, 26, 30}, { 17, 21, 25, 28}, { 16, 20, 23, 27}, { 15, 19, 22, 25}, { 14, 18, 21, 24}, { 14, 17, 20, 23}, { 13, 16, 19, 22}, { 12, 15, 18, 21}, { 12, 14, 17, 20}, { 11, 14, 16, 19}, { 11, 13, 15, 18}, { 10, 12, 15, 17}, { 10, 12, 14, 16}, { 9, 11, 13, 15}, { 9, 11, 12, 14}, { 8, 10, 12, 14}, { 8, 9, 11, 13}, { 7, 9, 11, 12}, { 7, 9, 10, 12}, { 7, 8, 10, 11}, { 6, 8, 9, 11}, { 6, 7, 9, 10}, { 6, 7, 8, 9}, { 2, 2, 2, 2} }; const unsigned short AC_next_state_MPS_64[64] = { 1,2,3,4,5,6,7,8,9,10, 11,12,13,14,15,16,17,18,19,20, 21,22,23,24,25,26,27,28,29,30, 31,32,33,34,35,36,37,38,39,40, 41,42,43,44,45,46,47,48,49,50, 51,52,53,54,55,56,57,58,59,60, 61,62,62,63 }; const unsigned short AC_next_state_LPS_64[64] = { 0, 0, 1, 2, 2, 4, 4, 5, 6, 7, 8, 9, 9,11,11,12,13,13,15,15, 16,16,18,18,19,19,21,21,22,22, 23,24,24,25,26,26,27,27,28,29, 29,30,30,30,31,32,32,33,33,33, 34,34,35,35,35,36,36,36,37,37, 37,38,38,63 }; /************************************************************************ * M a c r o s ************************************************************************ */ #define get_byte(){ \ Dbuffer = Dcodestrm[(*Dcodestrm_len)++];\ Dbits_to_go = 7; \ } /************************************************************************ ************************************************************************ init / exit decoder ************************************************************************ ************************************************************************/ /*! ************************************************************************ * \brief * Allocates memory for the DecodingEnvironment struct * \return DecodingContextPtr * allocates memory ************************************************************************ */ DecodingEnvironmentPtr arideco_create_decoding_environment() { DecodingEnvironmentPtr dep; if ((dep = calloc(1,sizeof(DecodingEnvironment))) == NULL) no_mem_exit("arideco_create_decoding_environment: dep"); return dep; } /*! *********************************************************************** * \brief * Frees memory of the DecodingEnvironment struct *********************************************************************** */ void arideco_delete_decoding_environment(DecodingEnvironmentPtr dep) { if (dep == NULL) { snprintf(errortext, ET_SIZE, "Error freeing dep (NULL pointer)"); error (errortext, 200); } else free(dep); } /*! ************************************************************************ * \brief * Initializes the DecodingEnvironment for the arithmetic coder ************************************************************************ */ void arideco_start_decoding(DecodingEnvironmentPtr dep, unsigned char *cpixcode, int firstbyte, int *cpixcode_len, int slice_type ) { int value = 0; Dcodestrm = cpixcode; Dcodestrm_len = cpixcode_len; *Dcodestrm_len = firstbyte; { int i; Dbits_to_go = 0; for (i = 0; i < B_BITS -1 ; i++) // insertion of redundant bit { if (--Dbits_to_go < 0) get_byte(); value = (value<<1) | ((Dbuffer >> Dbits_to_go) & 0x01); } } dep->Drange = HALF-2; dep->Dvalue = value; } /*! ************************************************************************ * \brief * arideco_bits_read ************************************************************************ */ int arideco_bits_read(DecodingEnvironmentPtr dep) { return 8 * ((*Dcodestrm_len)-1) + (8 - Dbits_to_go) - 16; } /*! ************************************************************************ * \brief * arideco_done_decoding(): ************************************************************************ */ void arideco_done_decoding(DecodingEnvironmentPtr dep) { (*Dcodestrm_len)++; } /*! ************************************************************************ * \brief * biari_decode_symbol(): * \return * the decoded symbol ************************************************************************ */ unsigned int biari_decode_symbol(DecodingEnvironmentPtr dep, BiContextTypePtr bi_ct ) { register unsigned int bit = bi_ct->MPS; register unsigned int value = dep->Dvalue; register unsigned int range = dep->Drange; register unsigned int rLPS = (unsigned int) rLPS_table_64x4[bi_ct->state][(range>>6) & 0x03]; #if (2==TRACE) fprintf(p_trace, "%d 0x%04x %d %d\n", binCount++, dep->Drange, bi_ct->state, bi_ct->MPS ); #endif range -= rLPS; if (value < range) /* MPS */ bi_ct->state = AC_next_state_MPS_64[bi_ct->state]; // next state else /* LPS */ { value -= range; range = rLPS; bit = !bit; if (!bi_ct->state) // switch meaning of MPS if necessary bi_ct->MPS ^= 0x01; bi_ct->state = AC_next_state_LPS_64[bi_ct->state]; // next state } while (range < QUARTER) { /* Double range */ range <<= 1; if (--Dbits_to_go < 0) get_byte(); /* Shift in next bit and add to value */ value = (value << 1) | ((Dbuffer >> Dbits_to_go) & 0x01); } dep->Drange = range; dep->Dvalue = value; return(bit); } /*! ************************************************************************ * \brief * biari_decode_symbol_eq_prob(): * \return * the decoded symbol ************************************************************************ */ unsigned int biari_decode_symbol_eq_prob(DecodingEnvironmentPtr dep) { register unsigned int bit = 0; register unsigned int value = (dep->Dvalue<<1); #if TRACE // fprintf(p_trace, "%d 0x%04x\n", binCount++, dep->Drange ); #endif if (--Dbits_to_go < 0) get_byte(); /* Shift in next bit and add to value */ value |= (Dbuffer >> Dbits_to_go) & 0x01; if (value >= dep->Drange) { bit = 1; value -= dep->Drange; } dep->Dvalue = value; return(bit); } /*! ************************************************************************ * \brief * biari_decode_symbol_final(): * \return * the decoded symbol ************************************************************************ */ unsigned int biari_decode_final(DecodingEnvironmentPtr dep) { register unsigned int value = dep->Dvalue; register unsigned int range = dep->Drange - 2; #if (2==TRACE) fprintf(p_trace, "%d 0x%04x\n", binCount++, dep->Drange ); #endif if (value >= range) { return 1; } else { while (range < QUARTER) { /* Double range */ range <<= 1; if (--Dbits_to_go < 0) get_byte(); /* Shift in next bit and add to value */ value = (value << 1) | ((Dbuffer >> Dbits_to_go) & 0x01); } dep->Dvalue = value; dep->Drange = range; return 0; } } /*! ************************************************************************ * \brief * Initializes a given context with some pre-defined probability state ************************************************************************ */ void biari_init_context (struct img_par* img, BiContextTypePtr ctx, const int* ini) { int pstate; pstate = ((ini[0]* imax(0,img->qp) )>>4) + ini[1]; pstate = iClip3(1, 126, pstate); if ( pstate >= 64 ) { ctx->state = (unsigned short) (pstate - 64); ctx->MPS = 1; } else { ctx->state = (unsigned short) (63 - pstate); ctx->MPS = 0; } }