h.264

H.264编码解码器源码(c语言版本)

/*!
 **************************************************************************************
 * \file
 *    parset.c
 * \brief
 *    Picture and Sequence Parameter set generation and handling
 *  \date 25 November 2002
 * \author
 *    Main contributors (see contributors.h for copyright, address and affiliation details) 
 *      - Stephan Wenger        <[e-mail]>
 *
 **************************************************************************************
 */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <malloc.h>
#include <string.h>
 
#include "global.h"
#include "contributors.h"
#include "parsetcommon.h"
#include "nalu.h"
#include "parset.h"
#include "fmo.h"
#include "vlc.h"

// Local helpers
static int IdentifyProfile();
static int IdentifyLevel();
static int IdentifyNumRefFrames();
static int GenerateVUISequenceParameters();


/*! 
 *************************************************************************************
 * \brief
 *    generates a sequence and picture parameter set and stores these in global
 *    active_sps and active_pps
 *
 * \param 
 *    None.
 *
 * \return
 *    A NALU containing the Sequence ParameterSet
 *
 *************************************************************************************
*/
void GenerateParameterSets ()
{
  seq_parameter_set_rbsp_t *sps = NULL; 
  pic_parameter_set_rbsp_t *pps = NULL;

  sps = AllocSPS();
  pps = AllocPPS();

  FillParameterSetStructures (sps, pps);
	
  active_sps = sps;
  active_pps = pps;
}

/*! 
*************************************************************************************
* \brief
*    frees global parameter sets active_sps and active_pps
*
* \param 
*    None.
*
* \return
*    A NALU containing the Sequence ParameterSet
*
*************************************************************************************
*/
void FreeParameterSets ()
{
  FreeSPS (active_sps);
  FreePPS (active_pps);
}

/*! 
*************************************************************************************
* \brief
*    int GenerateSeq_parameter_set_NALU ();
*
* \param 
*    None.  Uses the global variables through FillParameterSetStructures()
*
* \return
*    A NALU containing the Sequence ParameterSet
*
*************************************************************************************
*/

NALU_t *GenerateSeq_parameter_set_NALU ()
{
  NALU_t *n = AllocNALU(64000);
  int RBSPlen = 0;
  int NALUlen;
  byte rbsp[MAXRBSPSIZE];
	
  RBSPlen = GenerateSeq_parameter_set_rbsp (active_sps, rbsp);
  NALUlen = RBSPtoNALU (rbsp, n, RBSPlen, NALU_TYPE_SPS, NALU_PRIORITY_HIGHEST, 0, 1);
  n->startcodeprefix_len = 4;
	
  return n;
}


/*! 
*************************************************************************************
* \brief
*    NALU_t *GeneratePic_parameter_set_NALU ();
*
* \param 
*    None.  Uses the global variables through FillParameterSetStructures()
*
* \return
*    A NALU containing the Picture Parameter Set
*
*************************************************************************************
*/

NALU_t *GeneratePic_parameter_set_NALU()
{
  NALU_t *n = AllocNALU(64000);
  int RBSPlen = 0;
  int NALUlen;
  byte rbsp[MAXRBSPSIZE];
	
  RBSPlen = GeneratePic_parameter_set_rbsp (active_pps, rbsp);
  NALUlen = RBSPtoNALU (rbsp, n, RBSPlen, NALU_TYPE_PPS, NALU_PRIORITY_HIGHEST, 0, 1);
  n->startcodeprefix_len = 4;
	
  return n;
}

/*!
 ************************************************************************
 * \brief
 *    FillParameterSetStructures: extracts info from global variables and
 *    generates a picture and sequence parameter set structure
 *
 * \par Input:
 *    seq_parameter_set_rbsp_t *sps,  Sequence parameter set to be filled
 *    pic_parameter_set_rbsp_t *pps   Picture parameter set to be filled
 * \par
 *    Function reads all kinds of values from several global variables,
 *    including input-> and image-> and fills in the sps and pps.  Many
 *    values are current hard-coded to defaults, especially most of the
 *    VUI stuff.  Currently, the sps and pps structures are fixed length
 *    with the exception of the fully flexible FMO map (mode 6).  This
 *    mode is not supported.  Hence, the function does not need to
 *    allocate memory for the FMOmap, the pointer slice_group_id is
 *    always NULL.  If one wants to implement FMO mode 6, one would need
 *    to malloc the memory for the map here, and the caller would need
 *    to free it after use.
 *
 * \par 
 *    Limitations
 *    Currently, the encoder does not support multiple parameter sets,
 *    primarily because the config file does not support it.  Hence the
 *    pic_parameter_set_id and the seq_parameter_set_id are always zero.
 *    If one day multiple parameter sets are implemented, it would
 *    make sense to break this function into two, one for the picture and
 *    one for the sequence.
 *    Currently, FMO is not supported
 *    The following pps and sps elements seem not to be used in the encoder 
 *    or decoder and, hence, a guessed default value is conveyed:
 *
 *    pps->num_ref_idx_l0_active_minus1 = img->num_ref_pic_active_fwd_minus1;
 *    pps->num_ref_idx_l1_active_minus1 = img->num_ref_pic_active_bwd_minus1;
 *    pps->chroma_qp_index_offset = 0;
 *    sps->required_frame_num_update_behaviour_flag = FALSE;
 *    sps->direct_temporal_constrained_flag = FALSE;
 *
 * \par
 *    Regarding the QP
 *    The previous software versions coded the absolute QP only in the 
 *    slice header.  This is kept, and the offset in the PPS is coded 
 *    even if we could save bits by intelligently using this field.
 *
 ************************************************************************
 */

void FillParameterSetStructures (seq_parameter_set_rbsp_t *sps, 
                                 pic_parameter_set_rbsp_t *pps)
{
  unsigned i;
  // *************************************************************************
  // Sequence Parameter Set
  // *************************************************************************
  assert (sps != NULL);
  assert (pps != NULL);
  // Profile and Level should be calculated using the info from the config
  // file.  Calculation is hidden in IndetifyProfile() and IdentifyLevel()
  sps->profile_idc = IdentifyProfile();
  sps->level_idc = IdentifyLevel();

#ifdef G50_SPS
  // needs to be set according to profile
  sps->constrained_set0_flag = 0;
  sps->constrained_set1_flag = 0;
  sps->constrained_set2_flag = 0;
#else
  sps->more_than_one_slice_group_allowed_flag = (input->FmoType!=0);
  // no out of order slice support
  sps->arbitrary_slice_order_allowed_flag = 0;
  sps->redundant_slices_allowed_flag = (input->redundant_slice_flag);
#endif

  // Parameter Set ID hardcoded to zero
  sps->seq_parameter_set_id = 0;

  //! POC stuff:
  //! The following values are hard-coded in init_poc().  Apparently,
  //! the poc implementation covers only a subset of the poc functionality.
  //! Here, the same subset is implemented.  Changes in the POC stuff have
  //! also to be reflected here
  sps->log2_max_frame_num_minus4 = LOG2_MAX_FRAME_NUM_MINUS4;
  sps->log2_max_pic_order_cnt_lsb_minus4 = LOG2_MAX_PIC_ORDER_CNT_LSB_MINUS4;   // POC200301
  sps->pic_order_cnt_type = img->pic_order_cnt_type;
  sps->num_ref_frames_in_pic_order_cnt_cycle = img->num_ref_frames_in_pic_order_cnt_cycle;
  sps->delta_pic_order_always_zero_flag = img->delta_pic_order_always_zero_flag;
  sps->offset_for_non_ref_pic = img->offset_for_non_ref_pic;
  sps->offset_for_top_to_bottom_field = img->offset_for_top_to_bottom_field;
  // This is the only one used, because num_ref_frames_in_pic_order_cnt_cycle 
  // is hard coded to 1.  
  sps->offset_for_ref_frame[0] = img->offset_for_ref_frame[0];
  // End of POC stuff

  // Number of Reference Frames
  sps->num_ref_frames = IdentifyNumRefFrames();

  //required_frame_num_update_behaviour_flag hardcoded to zero
  sps->gaps_in_frame_num_value_allowed_flag = FALSE;    // double check

  sps->frame_mbs_only_flag = (input->InterlaceCodingOption == FRAME_CODING);

  // Picture size, finally a simple one :-)
  sps->pic_width_in_mbs_minus1 = (input->img_width/16) -1;
  sps->pic_height_in_map_units_minus1 = ((input->img_height/16)/ (2 - sps->frame_mbs_only_flag)) - 1;

  // a couple of flags, simple
  sps->mb_adaptive_frame_field_flag = (input->InterlaceCodingOption == MB_CODING);
  sps->direct_8x8_inference_flag = FALSE;

  // Sequence VUI not implemented, signalled as not present
  sps->vui_parameters_present_flag = FALSE;

  // *************************************************************************
  // Picture Parameter Set 
  // *************************************************************************

  pps->seq_parameter_set_id = 0;
  pps->pic_parameter_set_id = 0;
  pps->entropy_coding_mode_flag = (input->symbol_mode==UVLC?0:1);

  // JVT-Fxxx (by Stephan Wenger, make this flag unconditional
  pps->pic_order_present_flag = img->pic_order_present_flag;


  // Begin FMO stuff
  pps->num_slice_groups_minus1 = input->num_slice_groups_minus1;

  if (pps->num_slice_groups_minus1 > 0)
    switch (input->mb_allocation_map_type)
    {
    case 0:
      pps->slice_group_map_type = 6;       // This implementation always uses the fully flexible map
      printf ("Param.c: FMO type 0 not yet signalled, using 6 instead\n");
      goto FMOTYPE6;
      // This code should work as soon as the re-generation of the MBAmap in
      // the decoder does its job
      // pps->mb_slice_group_map_type = 0;    // according to the draft
      // for (i=0; i< pps->num_slice_groups_minus1+1; i++)
      //   pps->run_length[i] = img->width/16;    // Line interleaving
      break;
    case 1:
      pps->slice_group_map_type = 6;       // This implementation always uses the fully flexible map
      printf ("Param.c: FMO type 1 not yet signalled, using 6 instead\n");
      goto FMOTYPE6;
      // This code should work as soon as the re-generation of the MBAmap in
      // the decoder does its job
      // pps->mb_slice_group_map_type = 1;    // according to the draft
      break;
    case 2:
      assert(pps->num_slice_groups_minus1 == 1);      // restriction of the config file
      for(i=0; i<pps->num_slice_groups_minus1; i++)
      {
        pps->top_left[i] = input->top_left_mb;
        pps->bottom_right[i] = input->bottom_right_mb;
      }
     break;
    case 3:
    case 4:
    case 5:
      pps->slice_group_change_direction_flag = input->slice_group_change_direction;
      pps->slice_group_change_rate_minus1 = input->slice_group_change_rate_minus1;
      break;
    case 6:
FMOTYPE6:
      pps->slice_group_map_type = 6;       // This implementation always uses the fully flexible map
      pps->num_slice_group_map_units_minus1 = (img->height/16) * (img->width/16) - 1;
      for (i=0;i<=pps->num_slice_group_map_units_minus1; i++)
        pps->slice_group_id[i++] = FmoMB2SliceGroup (i);
      break;
    default:
      printf ("Param.c: FMO type invalid, default\n");
      assert (0==1);
    }
// End FMO stuff

  pps->num_ref_idx_l0_active_minus1 = img->num_ref_idx_l0_active-1;   // check this
  pps->num_ref_idx_l1_active_minus1 = img->num_ref_idx_l1_active-1;   // check this
  
  pps->weighted_pred_flag = input->WeightedPrediction;