parset.c

H.264视频编码器(ITU的264编码参考软件)

/*!
 **************************************************************************************
 * \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 <stdlib.h>
#include <assert.h>
 
#include "global.h"

#include "contributors.h"
#include "mbuffer.h"
#include "parset.h"
#include "vlc.h"

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

extern ColocatedParams *Co_located;


/*! 
 *************************************************************************************
 * \brief
 *    generates a sequence and picture parameter set and stores these in global
 *    active_sps and active_pps
 *
 * \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
*
* \return
*    A NALU containing the Sequence ParameterSet
*
*************************************************************************************
*/
void FreeParameterSets ()
{
  FreeSPS (active_sps);
  FreePPS (active_pps);
}

/*! 
*************************************************************************************
* \brief
*    int GenerateSeq_parameter_set_NALU ();
*
* \note
*    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 ();
*
* \note
*    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
 *
 * \param sps
 *    Sequence parameter set to be filled
 * \param 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;
  int frext_profile = ((IdentifyProfile()==FREXT_HP) || 
                      (IdentifyProfile()==FREXT_Hi10P) ||
                      (IdentifyProfile()==FREXT_Hi422) ||
                      (IdentifyProfile()==FREXT_Hi444));

  // *************************************************************************
  // 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();

  // needs to be set according to profile
  sps->constrained_set0_flag = 0;
  sps->constrained_set1_flag = 0;
  sps->constrained_set2_flag = 0;
  sps->constrained_set3_flag = 0;

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

  // Fidelity Range Extensions stuff
  sps->bit_depth_luma_minus8   = input->BitDepthLuma - 8;
  sps->bit_depth_chroma_minus8 = input->BitDepthChroma - 8;
  img->lossless_qpprime_flag = input->lossless_qpprime_y_zero_flag & (sps->profile_idc==FREXT_Hi444);
  img->residue_transform_flag = input->residue_transform_flag;
  
  //! 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;
  
  sps->pic_order_cnt_type = input->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;

  for (i=0; i<img->num_ref_frames_in_pic_order_cnt_cycle; i++)
  {
    sps->offset_for_ref_frame[i] = img->offset_for_ref_frame[i];
  }
  // 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->PicInterlace || input->MbInterlace);

  // 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 = (FRAME_CODING != input->MbInterlace);
  sps->direct_8x8_inference_flag = input->directInferenceFlag;
  
  // Sequence VUI not implemented, signalled as not present
  sps->vui_parameters_present_flag = (input->rgb_input_flag && input->yuv_format==3);

  {
    int PicWidthInMbs, PicHeightInMapUnits, FrameHeightInMbs;
    int width, height;
    PicWidthInMbs = (sps->pic_width_in_mbs_minus1 +1);
    PicHeightInMapUnits = (sps->pic_height_in_map_units_minus1 +1);
    FrameHeightInMbs = ( 2 - sps->frame_mbs_only_flag ) * PicHeightInMapUnits;
    
    width = PicWidthInMbs * MB_BLOCK_SIZE;
    height = FrameHeightInMbs * MB_BLOCK_SIZE;
    
    Co_located = alloc_colocated (width, height,sps->mb_adaptive_frame_field_flag);
    
  }
  // *************************************************************************
  // 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);

  // Fidelity Range Extensions stuff
  if(frext_profile)
  {
    pps->transform_8x8_mode_flag = input->AllowTransform8x8 ? 1:0;

    sps->seq_scaling_matrix_present_flag = (input->ScalingMatrixPresentFlag&1);
    for(i=0; i<8; i++)
    {