image.c

H.264视频编解码的标准测试模型

  expected_slice_type = NALU_TYPE_DPA;

  while (1)
  {
    ftell_position = ftell(bits);

    if (input->FileFormat == PAR_OF_ANNEXB)
      ret=GetAnnexbNALU (nalu);
    else
      ret=GetRTPNALU (nalu);

    //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(nalu, &ret);

    NALUtoRBSP(nalu);
//    printf ("nalu->len %d\n", nalu->len);
    
    if (ret < 0)
      printf ("Error while getting the NALU in file format %s, exit\n", input->FileFormat==PAR_OF_ANNEXB?"Annex B":"RTP");
    if (ret == 0)
    {
//      printf ("read_new_slice: returning %s\n", "EOS");
      if(expected_slice_type != NALU_TYPE_DPA)
      {
        /* oops... we found the next slice, go back! */
        fseek(bits, ftell_position, SEEK_SET);
        FreeNALU(nalu);
        return current_header;
      }
      else
        return EOS;
    }

    // Got a NALU
    if (nalu->forbidden_bit)
    {
      printf ("Found NALU w/ forbidden_bit set, bit error?  Let's try...\n");
    }

    switch (nalu->nal_unit_type)
    {
      case NALU_TYPE_SLICE:
      case NALU_TYPE_IDR:
        img->idr_flag = (nalu->nal_unit_type == NALU_TYPE_IDR);
        img->nal_reference_idc = nalu->nal_reference_idc;
        img->disposable_flag = (nalu->nal_reference_idc == NALU_PRIORITY_DISPOSABLE);
        currSlice->dp_mode = PAR_DP_1;
        currSlice->max_part_nr = 1;
        currSlice->ei_flag = 0;
        currStream = currSlice->partArr[0].bitstream;
        currStream->ei_flag = 0;
        currStream->frame_bitoffset = currStream->read_len = 0;
        memcpy (currStream->streamBuffer, &nalu->buf[1], nalu->len-1);
        currStream->code_len = currStream->bitstream_length = RBSPtoSODB(currStream->streamBuffer, nalu->len-1);

        // Some syntax of the Slice Header depends on the parameter set, which depends on
        // the parameter set ID of the SLice header.  Hence, read the pic_parameter_set_id
        // of the slice header first, then setup the active parameter sets, and then read
        // the rest of the slice header
        BitsUsedByHeader = FirstPartOfSliceHeader();
        UseParameterSet (currSlice->pic_parameter_set_id);
        BitsUsedByHeader+= RestOfSliceHeader ();

        FmoInit (active_pps, active_sps);

        AssignQuantParam (active_pps, active_sps);

        if(is_new_picture())
        {
          init_picture(img, input);
          
          current_header = SOP;
          //check zero_byte if it is also the first NAL unit in the access unit
          CheckZeroByteVCL(nalu, &ret);
        }
        else
          current_header = SOS;
  
        init_lists(img->type, img->currentSlice->structure);
        reorder_lists (img->type, img->currentSlice);

        if (img->structure==FRAME)
        {
          init_mbaff_lists();
        }

/*        if (img->frame_num==1) // write a reference list
        {
          count ++;
          if (count==1)
            for (i=0; i<listXsize[0]; i++)
              write_picture(listX[0][i], p_out2);
        }
*/

        // From here on, active_sps, active_pps and the slice header are valid
        if (img->MbaffFrameFlag)
          img->current_mb_nr = currSlice->start_mb_nr << 1;
        else
          img->current_mb_nr = currSlice->start_mb_nr;

        if (active_pps->entropy_coding_mode_flag)
        {
          int ByteStartPosition = currStream->frame_bitoffset/8;
          if (currStream->frame_bitoffset%8 != 0) 
          {
            ByteStartPosition++;
          }
          arideco_start_decoding (&currSlice->partArr[0].de_cabac, currStream->streamBuffer, ByteStartPosition, &currStream->read_len, img->type);
        }
// printf ("read_new_slice: returning %s\n", current_header == SOP?"SOP":"SOS");
        FreeNALU(nalu);
        return current_header;
        break;
      case NALU_TYPE_DPA:
        //! The state machine here should follow the same ideas as the old readSliceRTP()
        //! basically:
        //! work on DPA (as above)
        //! read and process all following SEI/SPS/PPS/PD/Filler NALUs
        //! if next video NALU is dpB, 
        //!   then read and check whether it belongs to DPA, if yes, use it
        //! else
        //!   ;   // nothing
        //! read and process all following SEI/SPS/PPS/PD/Filler NALUs
        //! if next video NALU is dpC
        //!   then read and check whether it belongs to DPA (and DPB, if present), if yes, use it, done
        //! else
        //!   use the DPA (and the DPB if present)

        /* 
            LC: inserting the code related to DP processing, mainly copying some of the parts
            related to NALU_TYPE_SLICE, NALU_TYPE_IDR.
        */

        if(expected_slice_type != NALU_TYPE_DPA)
        {
          /* oops... we found the next slice, go back! */
          fseek(bits, ftell_position, SEEK_SET);
          FreeNALU(nalu);
          return current_header;
        }

        img->idr_flag          = (nalu->nal_unit_type == NALU_TYPE_IDR);
        img->nal_reference_idc = nalu->nal_reference_idc;
        img->disposable_flag   = (nalu->nal_reference_idc == NALU_PRIORITY_DISPOSABLE);
        currSlice->dp_mode     = PAR_DP_3;
        currSlice->max_part_nr = 3;
        currSlice->ei_flag     = 0;
        currStream             = currSlice->partArr[0].bitstream;
        currStream->ei_flag    = 0;
        currStream->frame_bitoffset = currStream->read_len = 0;
        memcpy (currStream->streamBuffer, &nalu->buf[1], nalu->len-1);
        currStream->code_len = currStream->bitstream_length = RBSPtoSODB(currStream->streamBuffer, nalu->len-1);
        
        BitsUsedByHeader     = FirstPartOfSliceHeader();
        UseParameterSet (currSlice->pic_parameter_set_id);
        BitsUsedByHeader    += RestOfSliceHeader ();
        
        FmoInit (active_pps, active_sps);
        
        if(is_new_picture())
        {
          init_picture(img, input);
          current_header = SOP;
          CheckZeroByteVCL(nalu, &ret);
        }
        else
          current_header = SOS;

        
        init_lists(img->type, img->currentSlice->structure);
        reorder_lists (img->type, img->currentSlice);
        
        if (img->structure==FRAME)
        {
          init_mbaff_lists();
        }

        // From here on, active_sps, active_pps and the slice header are valid
        if (img->MbaffFrameFlag)
          img->current_mb_nr = currSlice->start_mb_nr << 1;
        else
          img->current_mb_nr = currSlice->start_mb_nr;


        /* 
           LC:
              Now I need to read the slice ID, which depends on the value of 
              redundant_pic_cnt_present_flag (pag.49). 
        */
        
        slice_id_a  = ue_v("NALU:SLICE_A slice_idr", currStream);
        if (active_pps->entropy_coding_mode_flag)
        {
          int ByteStartPosition = currStream->frame_bitoffset/8;
          if (currStream->frame_bitoffset%8 != 0) 
          {
            ByteStartPosition++;
          }
          arideco_start_decoding (&currSlice->partArr[0].de_cabac, currStream->streamBuffer, ByteStartPosition, &currStream->read_len, img->type);
        }
// printf ("read_new_slice: returning %s\n", current_header == SOP?"SOP":"SOS");
        break;
      case NALU_TYPE_DPB:
        /* LC: inserting the code related to DP processing */

        currStream             = currSlice->partArr[1].bitstream;
        currStream->ei_flag    = 0;
        currSlice->dp_mode     = PAR_DP_3;
        currStream->frame_bitoffset = currStream->read_len = 0;
        memcpy (currStream->streamBuffer, &nalu->buf[1], nalu->len-1);
        currStream->code_len = currStream->bitstream_length = RBSPtoSODB(currStream->streamBuffer, nalu->len-1);

        slice_id_b  = ue_v("NALU:SLICE_B slice_idr", currStream);
        if (active_pps->redundant_pic_cnt_present_flag)
          redundant_pic_cnt_b = ue_v("NALU:SLICE_B redudand_pic_cnt", currStream);
        else
          redundant_pic_cnt_b = 0;
        
        /*  LC: Initializing CABAC for the current data stream. */

        if (active_pps->entropy_coding_mode_flag)
        {
          int ByteStartPosition = currStream->frame_bitoffset/8;
          if (currStream->frame_bitoffset % 8 != 0) 
            ByteStartPosition++;
          
          arideco_start_decoding (&currSlice->partArr[1].de_cabac, currStream->streamBuffer, 
            ByteStartPosition, &currStream->read_len, img->type);
          
        }

        /* LC: resilience code to be inserted */
        /*         FreeNALU(nalu); */
        /*         return current_header; */

        break;
      case NALU_TYPE_DPC:
        /* LC: inserting the code related to DP processing */
        currSlice->dp_mode     = PAR_DP_3;
        currStream             = currSlice->partArr[2].bitstream;
        currStream->ei_flag    = 0;
        currStream->frame_bitoffset = currStream->read_len = 0;
        memcpy (currStream->streamBuffer, &nalu->buf[1], nalu->len-1);
        currStream->code_len = currStream->bitstream_length = RBSPtoSODB(currStream->streamBuffer, nalu->len-1);
        
        slice_id_c  = ue_v("NALU:SLICE_C slice_idr", currStream);
        if (active_pps->redundant_pic_cnt_present_flag)
          redundant_pic_cnt_c = ue_v("NALU:SLICE_C redudand_pic_cnt", currStream);
        else
          redundant_pic_cnt_c = 0;
        
        /* LC: Initializing CABAC for the current data stream. */

        if (active_pps->entropy_coding_mode_flag)
        {
          int ByteStartPosition = currStream->frame_bitoffset/8;
          if (currStream->frame_bitoffset % 8 != 0) 
            ByteStartPosition++;
          
          arideco_start_decoding (&currSlice->partArr[2].de_cabac, currStream->streamBuffer, 
            ByteStartPosition, &currStream->read_len, img->type);
        }

        /* LC: resilience code to be inserted */

        FreeNALU(nalu);
        return current_header;

        break;
      case NALU_TYPE_SEI:
        printf ("read_new_slice: Found NALU_TYPE_SEI, len %d\n", nalu->len);
        InterpretSEIMessage(nalu->buf,nalu->len,img);
        break;
      case NALU_TYPE_PPS:
        ProcessPPS(nalu);
        break;

      case NALU_TYPE_SPS:
        ProcessSPS(nalu);
        break;
      case NALU_TYPE_AUD:
//        printf ("read_new_slice: Found 'Access Unit Delimiter' NAL unit, len %d, ignored\n", nalu->len);
        break;
      case NALU_TYPE_EOSEQ:
//        printf ("read_new_slice: Found 'End of Sequence' NAL unit, len %d, ignored\n", nalu->len);
        break;
      case NALU_TYPE_EOSTREAM:
//        printf ("read_new_slice: Found 'End of Stream' NAL unit, len %d, ignored\n", nalu->len);
        break;
      case NALU_TYPE_FILL:
        printf ("read_new_slice: Found NALU_TYPE_FILL, len %d\n", nalu->len);
        printf ("Skipping these filling bits, proceeding w/ next NALU\n");
        break;
      default:
        printf ("Found NALU type %d, len %d undefined, ignore NALU, moving on\n", nalu->nal_unit_type, nalu->len);
    }
  }
  FreeNALU(nalu);

  return  current_header;
}


/*!
 ************************************************************************
 * \brief
 *    Initializes the parameters for a new picture
 ************************************************************************
 */
void init_picture(struct img_par *img, struct inp_par *inp)
{
  int i,k,l;
  Slice *currSlice = img->currentSlice;

  if (dec_picture)
  {
    // this may only happen on slice loss
    exit_picture();
  }

  if (img->frame_num != img->pre_frame_num && img->frame_num != (img->pre_frame_num + 1) % img->MaxFrameNum) 
  {
    if (active_sps->gaps_in_frame_num_value_allowed_flag == 0)
    {
      // picture error concealment
      if(inp->conceal_mode !=0)
      {
        if((img->frame_num) < ((img->pre_frame_num + 1) % img->MaxFrameNum))
        {
          /* Conceal lost IDR frames and any frames immediately 
             following the IDR. Use frame copy for these since 
             lists cannot be formed correctly for motion copy*/
          img->conceal_mode = 1; 
          img->IDR_concealment_flag = 1;
          conceal_lost_frames(img);
          //reset to original concealment mode for future drops
          img->conceal_mode = inp->conceal_mode;
        }
        else
        {
          //reset to original concealment mode for future drops
          img->conceal_mode = inp->conceal_mode;

          img->IDR_concealment_flag = 0;
          conceal_lost_frames(img);
        }
      }
      else
      {   /* Advanced Error Concealment would be called here to combat unintentional loss of pictures. */
        error("An unintentional loss of pictures occurs! Exit\n", 100);
      }
    }
    if(img->conceal_mode == 0)
      fill_frame_num_gap(img);
  }

  if(img->nal_reference_idc)
  {
    img->pre_frame_num = img->frame_num;
  }

  //img->num_dec_mb = 0;
  
  //calculate POC
  decode_poc(img);