diff options
Diffstat (limited to 'Src/h264dec/ldecod/src/nalu.c')
| -rw-r--r-- | Src/h264dec/ldecod/src/nalu.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/Src/h264dec/ldecod/src/nalu.c b/Src/h264dec/ldecod/src/nalu.c new file mode 100644 index 00000000..e70617e3 --- /dev/null +++ b/Src/h264dec/ldecod/src/nalu.c @@ -0,0 +1,162 @@ + +/*! + ************************************************************************ + * \file nalu.c + * + * \brief + * Decoder NALU support functions + * + * \author + * Main contributors (see contributors.h for copyright, address and affiliation details) + * - Stephan Wenger <stewe@cs.tu-berlin.de> + ************************************************************************ + */ + +#include "global.h" +#include "nalu.h" +#include "memalloc.h" +#include "meminput.h" + +/*! +************************************************************************************* +* \brief +* Initialize bitstream reading structure +* +* \param +* p_Vid: Imageparameter information +* \param +* filemode: +* +************************************************************************************* +*/ +void OpenMemory(VideoParameters *p_Vid, const char *fn); +void CloseMemory(VideoParameters *p_Vid); +int GetMemoryNALU (VideoParameters *p_Vid, NALU_t *nalu); + +void initBitsFile (VideoParameters *p_Vid) +{ + malloc_mem_input(p_Vid); + p_Vid->nalu = AllocNALU(MAX_CODED_FRAME_SIZE); + +} + +/*! + ************************************************************************************* + * \brief + * Converts a NALU to an RBSP + * + * \param + * nalu: nalu structure to be filled + * + * \return + * length of the RBSP in bytes + ************************************************************************************* + */ + +static int NALUtoRBSP (NALU_t *nalu) +{ + assert (nalu != NULL); + + nalu->len = EBSPtoRBSP (nalu->buf, nalu->len) ; + + return nalu->len ; +} + +/*! +************************************************************************ +* \brief +* Read the next NAL unit (with error handling) +************************************************************************ +*/ +int read_next_nalu(VideoParameters *p_Vid, NALU_t *nalu) +{ + InputParameters *p_Inp = p_Vid->p_Inp; + int ret; + + ret = GetMemoryNALU(p_Vid, nalu); + + if (ret < 0) + { + error ("Error while getting the next NALU, exit\n", 601); + } + if (ret == 0) + { + return 0; + } + + //In some cases, zero_byte shall be present. If current NALU is a VCL NALU, we can't tell + //whether it is the first VCL NALU at this point, so only non-VCL NAL unit is checked here. + CheckZeroByteNonVCL(p_Vid, nalu); + + ret = NALUtoRBSP(nalu); + + if (ret < 0) + error ("Invalid startcode emulation prevention found.", 602); + + + // Got a NALU + if (nalu->forbidden_bit) + { + error ("Found NALU with forbidden_bit set, bit error?", 603); + } + + return nalu->len; +} + +void CheckZeroByteNonVCL(VideoParameters *p_Vid, NALU_t *nalu) +{ + int CheckZeroByte=0; + + //This function deals only with non-VCL NAL units + if(nalu->nal_unit_type>=1&&nalu->nal_unit_type<=5) + return; + + //for SPS and PPS, zero_byte shall exist + if(nalu->nal_unit_type==NALU_TYPE_SPS || nalu->nal_unit_type==NALU_TYPE_PPS) + CheckZeroByte=1; + //check the possibility of the current NALU to be the start of a new access unit, according to 7.4.1.2.3 + if(nalu->nal_unit_type==NALU_TYPE_AUD || nalu->nal_unit_type==NALU_TYPE_SPS || + nalu->nal_unit_type==NALU_TYPE_PPS || nalu->nal_unit_type==NALU_TYPE_SEI || + (nalu->nal_unit_type>=13 && nalu->nal_unit_type<=18)) + { + if(p_Vid->LastAccessUnitExists) + { + p_Vid->LastAccessUnitExists=0; //deliver the last access unit to decoder + p_Vid->NALUCount=0; + } + } + p_Vid->NALUCount++; + //for the first NAL unit in an access unit, zero_byte shall exists + if(p_Vid->NALUCount==1) + CheckZeroByte=1; + if(CheckZeroByte && nalu->startcodeprefix_len==3) + { + // printf("Warning: zero_byte shall exist\n"); + //because it is not a very serious problem, we do not exit here + } +} + +void CheckZeroByteVCL(VideoParameters *p_Vid, NALU_t *nalu) +{ + int CheckZeroByte=0; + + //This function deals only with VCL NAL units + if(!(nalu->nal_unit_type>=1&&nalu->nal_unit_type<=5)) + return; + + if(p_Vid->LastAccessUnitExists) + { + p_Vid->NALUCount=0; + } + p_Vid->NALUCount++; + //the first VCL NAL unit that is the first NAL unit after last VCL NAL unit indicates + //the start of a new access unit and hence the first NAL unit of the new access unit. (sounds like a tongue twister :-) + if(p_Vid->NALUCount == 1) + CheckZeroByte = 1; + p_Vid->LastAccessUnitExists = 1; + if(CheckZeroByte && nalu->startcodeprefix_len==3) + { + //printf("warning: zero_byte shall exist\n"); + //because it is not a very serious problem, we do not exit here + } +} |