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-rw-r--r--Src/h264dec/ldecod/src/biaridecod.c322
1 files changed, 322 insertions, 0 deletions
diff --git a/Src/h264dec/ldecod/src/biaridecod.c b/Src/h264dec/ldecod/src/biaridecod.c
new file mode 100644
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+++ b/Src/h264dec/ldecod/src/biaridecod.c
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+/*!
+ *************************************************************************************
+ * \file biaridecod.c
+ *
+ * \brief
+ * Binary arithmetic decoder routines.
+ *
+ * This modified implementation of the M Coder is based on JVT-U084
+ * with the choice of M_BITS = 16.
+ *
+ * \date
+ * 21. Oct 2000
+ * \author
+ * Main contributors (see contributors.h for copyright, address and affiliation details)
+ * - Detlev Marpe <marpe@hhi.de>
+ * - Gabi Blaettermann
+ * - Gunnar Marten
+ *************************************************************************************
+ */
+
+#include "global.h"
+#include "memalloc.h"
+#include "biaridecod.h"
+
+
+#define B_BITS 10 // Number of bits to represent the whole coding interval
+#define HALF 0x01FE //(1 << (B_BITS-1)) - 2
+#define QUARTER 0x0100 //(1 << (B_BITS-2))
+
+
+/************************************************************************
+ ************************************************************************
+ 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
+ * finalize arithetic decoding():
+ ************************************************************************
+ */
+void arideco_done_decoding(DecodingEnvironmentPtr dep)
+{
+ (*dep->Dcodestrm_len)++;
+#if(TRACE==2)
+ fprintf(p_trace, "done_decoding: %d\n", *dep->Dcodestrm_len);
+#endif
+}
+
+/*!
+ ************************************************************************
+ * \brief
+ * read one byte from the bitstream
+ ************************************************************************
+ */
+unsigned int getbyte(DecodingEnvironmentPtr dep)
+{
+#if(TRACE==2)
+ fprintf(p_trace, "get_byte: %d\n", (*dep->Dcodestrm_len));
+#endif
+ return dep->Dcodestrm[(*dep->Dcodestrm_len)++];
+}
+
+/*!
+ ************************************************************************
+ * \brief
+ * read two bytes from the bitstream
+ ************************************************************************
+ */
+
+static unsigned int getword(DecodingEnvironmentPtr dep)
+{
+ int d = *dep->Dcodestrm_len;
+ *dep->Dcodestrm_len += 2;
+ return ((dep->Dcodestrm[d]<<8) | dep->Dcodestrm[d+1]);
+}
+
+/*!
+ ************************************************************************
+ * \brief
+ * Initializes the DecodingEnvironment for the arithmetic coder
+ ************************************************************************
+ */
+void arideco_start_decoding(DecodingEnvironmentPtr dep, unsigned char *code_buffer,
+ int firstbyte, int *code_len)
+{
+
+ dep->Dcodestrm = code_buffer;
+ dep->Dcodestrm_len = code_len;
+ *dep->Dcodestrm_len = firstbyte;
+
+ dep->Dvalue = getbyte(dep);
+ dep->Dvalue = (dep->Dvalue << 16) | getword(dep); // lookahead of 2 bytes: always make sure that bitstream buffer
+ // contains 2 more bytes than actual bitstream
+ dep->DbitsLeft = 15;
+ dep->Drange = HALF;
+
+#if (2==TRACE)
+ fprintf(p_trace, "value: %d firstbyte: %d code_len: %d\n", dep->Dvalue >> dep->DbitsLeft, firstbyte, *code_len);
+#endif
+}
+
+
+
+
+/*!
+************************************************************************
+* \brief
+* biari_decode_symbol():
+* \return
+* the decoded symbol
+************************************************************************
+*/
+/* random notes
+max rLPS = 240 1111 1 111
+max state = 63
+max renorm = 6, min 1
+max bitsleft = 16
+max range = (1<<10) ????? (1024)
+*/
+#if !defined(_M_IX86) || defined(_DEBUG)
+unsigned int biari_decode_symbol(DecodingEnvironmentPtr dep, BiContextTypePtr bi_ct )
+{
+ unsigned int state = bi_ct->state;
+ unsigned int bit = bi_ct->MPS;
+ unsigned int value = dep->Dvalue;
+ unsigned int range = dep->Drange;
+ const unsigned int rLPS = rLPS_table_64x4[(range>>6)&3][state];
+
+ range -= rLPS;
+
+ if(value >= (range << dep->DbitsLeft))
+ { // LPS
+ int renorm;
+ bi_ct->state = AC_next_state_LPS_64[state]; // next state
+ value -= (range << dep->DbitsLeft);
+ bit ^= 0x01;
+
+ //if (!state) // switch meaning of MPS if necessary
+ // bi_ct->MPS = bit;
+ bi_ct->MPS ^= !state;//0x01;
+
+ renorm = renorm_table_256[rLPS];
+ range = (rLPS << renorm);
+
+ dep->Drange = range;
+ dep->DbitsLeft -= renorm;
+ if( dep->DbitsLeft > 0 )
+ {
+ dep->Dvalue = value;
+ return(bit);
+ }
+
+ dep->Dvalue = (value << 16) | getword(dep); // lookahead of 2 bytes: always make sure that bitstream buffer
+ // contains 2 more bytes than actual bitstream
+ dep->DbitsLeft += 16;
+
+ return(bit);
+ }
+ else
+ { //MPS
+ bi_ct->state = AC_next_state_MPS_64[state]; // next state
+
+ if( range < QUARTER )
+ {
+ dep->Drange = range << 1;
+ dep->DbitsLeft -= 1;
+ if( dep->DbitsLeft > 0 )
+ {
+ return(bit);
+ }
+
+ dep->Dvalue = (value << 16) | getword(dep); // lookahead of 2 bytes: always make sure that bitstream buffer
+ // contains 2 more bytes than actual bitstream
+ dep->DbitsLeft += 16;
+
+ return(bit);
+ }
+ else
+ {
+ dep->Drange = range;
+ return (bit);
+ }
+ }
+
+}
+#endif
+/*!
+ ************************************************************************
+ * \brief
+ * biari_decode_symbol_eq_prob():
+ * \return
+ * the decoded symbol
+ ************************************************************************
+ */
+unsigned int biari_decode_symbol_eq_prob(DecodingEnvironmentPtr dep)
+{
+ int tmp_value;
+ int value = dep->Dvalue;
+
+ if(--(dep->DbitsLeft) == 0)
+ {
+ value = (value << 16) | getword( dep ); // lookahead of 2 bytes: always make sure that bitstream buffer
+ // contains 2 more bytes than actual bitstream
+ dep->DbitsLeft = 16;
+ }
+ tmp_value = value - (dep->Drange << dep->DbitsLeft);
+
+ if (tmp_value < 0)
+ {
+ dep->Dvalue = value;
+ return 0;
+ }
+ else
+ {
+ dep->Dvalue = tmp_value;
+ return 1;
+ }
+}
+
+/*!
+ ************************************************************************
+ * \brief
+ * biari_decode_symbol_final():
+ * \return
+ * the decoded symbol
+ ************************************************************************
+ */
+unsigned int biari_decode_final(DecodingEnvironmentPtr dep)
+{
+ unsigned int range = dep->Drange - 2;
+ int value = dep->Dvalue;
+ value -= (range << dep->DbitsLeft);
+
+ if (value < 0)
+ {
+ if( range >= QUARTER )
+ {
+ dep->Drange = range;
+ return 0;
+ }
+ else
+ {
+ dep->Drange = (range << 1);
+ if( --(dep->DbitsLeft) > 0 )
+ return 0;
+ else
+ {
+ dep->Dvalue = (dep->Dvalue << 16) | getword( dep ); // lookahead of 2 bytes: always make sure that bitstream buffer
+ // contains 2 more bytes than actual bitstream
+ dep->DbitsLeft = 16;
+ return 0;
+ }
+ }
+ }
+ else
+ {
+ return 1;
+ }
+}
+
+/*!
+ ************************************************************************
+ * \brief
+ * Initializes a given context with some pre-defined probability state
+ ************************************************************************
+ */
+void biari_init_context (int qp, BiContextTypePtr ctx, const char* ini)
+{
+ int pstate = ((ini[0]* qp )>>4) + ini[1];
+
+ if ( pstate >= 64 )
+ {
+ pstate = imin(126, pstate);
+ ctx->state = (uint16) (pstate - 64);
+ ctx->MPS = 1;
+ }
+ else
+ {
+ pstate = imax(1, pstate);
+ ctx->state = (uint16) (63 - pstate);
+ ctx->MPS = 0;
+ }
+}
+
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