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H264参数语法文档： SPS、PPS、IDR
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From:?http://blog.csdn.net/heanyu/article/details/6205390
H.264碼流第一個 NALU 是 SPS（序列參數集Sequence Parameter Set）
對應H264標準文檔 7.3.2.1 序列參數集的語法進行解析
SPS參數解析// fill sps with content of p
[cpp] view plaincopy
int?InterpretSPS?(VideoParameters?*p_Vid,?DataPartition?*p,?seq_parameter_set_rbsp_t?*sps)??{????unsigned?i;????unsigned?n_ScalingList;????int?reserved_zero;????Bitstream?*s?=?p->bitstream;??????assert?(p?!=?NULL);????assert?(p->bitstream?!=?NULL);????assert?(p->bitstream->streamBuffer?!=?0);????assert?(sps?!=?NULL);??????p_Dec->UsedBits?=?0;??????sps->profile_idc????????????????????????????=?u_v??(8,?"SPS:?profile_idc"???????????????????????????,?s);??????if?((sps->profile_idc!=BASELINE???????)?&&????????(sps->profile_idc!=MAIN???????????)?&&????????(sps->profile_idc!=EXTENDED???????)?&&????????(sps->profile_idc!=FREXT_HP???????)?&&????????(sps->profile_idc!=FREXT_Hi10P????)?&&????????(sps->profile_idc!=FREXT_Hi422????)?&&????????(sps->profile_idc!=FREXT_Hi444????)?&&????????(sps->profile_idc!=FREXT_CAVLC444?)??#if?(MVC_EXTENSION_ENABLE)????????&&?(sps->profile_idc!=MVC_HIGH)????????&&?(sps->profile_idc!=STEREO_HIGH)??#endif????????)????{??????printf("Invalid?Profile?IDC?(%d)?encountered.?/n",?sps->profile_idc);??????return?p_Dec->UsedBits;????}??????sps->constrained_set0_flag??????????????????=?u_1??(???"SPS:?constrained_set0_flag"?????????????????,?s);????sps->constrained_set1_flag??????????????????=?u_1??(???"SPS:?constrained_set1_flag"?????????????????,?s);????sps->constrained_set2_flag??????????????????=?u_1??(???"SPS:?constrained_set2_flag"?????????????????,?s);????sps->constrained_set3_flag??????????????????=?u_1??(???"SPS:?constrained_set3_flag"?????????????????,?s);??#if?(MVC_EXTENSION_ENABLE)????sps->constrained_set4_flag??????????????????=?u_1??(???"SPS:?constrained_set4_flag"?????????????????,?s);????reserved_zero???????????????????????????????=?u_v??(3,?"SPS:?reserved_zero_3bits"???????????????????,?s);??#else????reserved_zero???????????????????????????????=?u_v??(4,?"SPS:?reserved_zero_4bits"???????????????????,?s);??#endif????assert?(reserved_zero==0);??????sps->level_idc??????????????????????????????=?u_v??(8,?"SPS:?level_idc"?????????????????????????????,?s);??????sps->seq_parameter_set_id???????????????????=?ue_v?("SPS:?seq_parameter_set_id"?????????????????????,?s);??????????sps->chroma_format_idc?=?1;????sps->bit_depth_luma_minus8???=?0;????sps->bit_depth_chroma_minus8?=?0;????p_Vid->lossless_qpprime_flag???=?0;????sps->separate_colour_plane_flag?=?0;??????if((sps->profile_idc==FREXT_HP???)?||???????(sps->profile_idc==FREXT_Hi10P)?||???????(sps->profile_idc==FREXT_Hi422)?||???????(sps->profile_idc==FREXT_Hi444)?||???????(sps->profile_idc==FREXT_CAVLC444)??#if?(MVC_EXTENSION_ENABLE)???????||?(sps->profile_idc==MVC_HIGH)???????||?(sps->profile_idc==STEREO_HIGH)??#endif???????)????{??????sps->chroma_format_idc??????????????????????=?ue_v?("SPS:?chroma_format_idc"???????????????????????,?s);????????if(sps->chroma_format_idc?==?YUV444)??????{????????sps->separate_colour_plane_flag???????????=?u_1??("SPS:?separate_colour_plane_flag"??????????????,?s);??????}????????sps->bit_depth_luma_minus8??????????????????=?ue_v?("SPS:?bit_depth_luma_minus8"???????????????????,?s);??????sps->bit_depth_chroma_minus8????????????????=?ue_v?("SPS:?bit_depth_chroma_minus8"?????????????????,?s);????????????if((sps->bit_depth_luma_minus8+8?>?sizeof(imgpel)*8)?||?(sps->bit_depth_chroma_minus8+8>?sizeof(imgpel)*8))????????error?("Source?picture?has?higher?bit?depth?than?imgpel?data?type.?/nPlease?recompile?with?larger?data?type?for?imgpel.",?500);????????p_Vid->lossless_qpprime_flag??????????????????=?u_1??("SPS:?lossless_qpprime_y_zero_flag"????????????,?s);????????sps->seq_scaling_matrix_present_flag????????=?u_1??(???"SPS:?seq_scaling_matrix_present_flag"???????,?s);????????????if(sps->seq_scaling_matrix_present_flag)??????{????????n_ScalingList?=?(sps->chroma_format_idc?!=?YUV444)???8?:?12;????????for(i=0;?iseq_scaling_list_present_flag[i]???=?u_1??(???"SPS:?seq_scaling_list_present_flag"?????????,?s);??????????if(sps->seq_scaling_list_present_flag[i])??????????{????????????if(i<6)?scaling_list="">ScalingList4x4[i],?16,?&sps->UseDefaultScalingMatrix4x4Flag[i],?s);????????????else??????????????Scaling_List(sps->ScalingList8x8[i-6],?64,?&sps->UseDefaultScalingMatrix8x8Flag[i-6],?s);??????????}????????}??????}????}??????sps->log2_max_frame_num_minus4??????????????=?ue_v?("SPS:?log2_max_frame_num_minus4"????????????????,?s);????sps->pic_order_cnt_type?????????????????????=?ue_v?("SPS:?pic_order_cnt_type"???????????????????????,?s);??????if?(sps->pic_order_cnt_type?==?0)??????sps->log2_max_pic_order_cnt_lsb_minus4?=?ue_v?("SPS:?log2_max_pic_order_cnt_lsb_minus4"???????????,?s);????else?if?(sps->pic_order_cnt_type?==?1)????{??????sps->delta_pic_order_always_zero_flag??????=?u_1??("SPS:?delta_pic_order_always_zero_flag"???????,?s);??????sps->offset_for_non_ref_pic????????????????=?se_v?("SPS:?offset_for_non_ref_pic"?????????????????,?s);??????sps->offset_for_top_to_bottom_field????????=?se_v?("SPS:?offset_for_top_to_bottom_field"?????????,?s);??????sps->num_ref_frames_in_pic_order_cnt_cycle?=?ue_v?("SPS:?num_ref_frames_in_pic_order_cnt_cycle"??,?s);??????for(i=0;?inum_ref_frames_in_pic_order_cnt_cycle;?i++)????????sps->offset_for_ref_frame[i]???????????????=?se_v?("SPS:?offset_for_ref_frame[i]"??????????????,?s);????}????sps->num_ref_frames????????????????????????=?ue_v?("SPS:?num_ref_frames"?????????????????????????,?s);????sps->gaps_in_frame_num_value_allowed_flag??=?u_1??("SPS:?gaps_in_frame_num_value_allowed_flag"???,?s);????sps->pic_width_in_mbs_minus1???????????????=?ue_v?("SPS:?pic_width_in_mbs_minus1"????????????????,?s);????sps->pic_height_in_map_units_minus1????????=?ue_v?("SPS:?pic_height_in_map_units_minus1"?????????,?s);????sps->frame_mbs_only_flag???????????????????=?u_1??("SPS:?frame_mbs_only_flag"????????????????????,?s);????if?(!sps->frame_mbs_only_flag)????{??????sps->mb_adaptive_frame_field_flag????????=?u_1??("SPS:?mb_adaptive_frame_field_flag"???????????,?s);????}????sps->direct_8x8_inference_flag?????????????=?u_1??("SPS:?direct_8x8_inference_flag"??????????????,?s);????sps->frame_cropping_flag???????????????????=?u_1??("SPS:?frame_cropping_flag"????????????????????,?s);??????if?(sps->frame_cropping_flag)????{??????sps->frame_cropping_rect_left_offset??????=?ue_v?("SPS:?frame_cropping_rect_left_offset"???????????,?s);??????sps->frame_cropping_rect_right_offset?????=?ue_v?("SPS:?frame_cropping_rect_right_offset"??????????,?s);??????sps->frame_cropping_rect_top_offset???????=?ue_v?("SPS:?frame_cropping_rect_top_offset"????????????,?s);??????sps->frame_cropping_rect_bottom_offset????=?ue_v?("SPS:?frame_cropping_rect_bottom_offset"?????????,?s);????}????sps->vui_parameters_present_flag???????????=?(Boolean)?u_1??("SPS:?vui_parameters_present_flag"??????,?s);??????InitVUI(sps);????ReadVUI(p,?sps);??????sps->Valid?=?TRUE;????return?p_Dec->UsedBits;??}??
H.264碼流第二個 NALU 是 PPS（圖像參數集Picture Parameter Set）
對應H264標準文檔 7.3.2.2 序列參數集的語法進行解析
PPS參數解析 [cpp] view plaincopy
int?InterpretPPS?(VideoParameters?*p_Vid,?DataPartition?*p,?pic_parameter_set_rbsp_t?*pps)??{????unsigned?i;????unsigned?n_ScalingList;????int?chroma_format_idc;????int?NumberBitsPerSliceGroupId;????Bitstream?*s?=?p->bitstream;??????assert?(p?!=?NULL);????assert?(p->bitstream?!=?NULL);????assert?(p->bitstream->streamBuffer?!=?0);????assert?(pps?!=?NULL);??????p_Dec->UsedBits?=?0;??????pps->pic_parameter_set_id??????????????????=?ue_v?("PPS:?pic_parameter_set_id"???????????????????,?s);????pps->seq_parameter_set_id??????????????????=?ue_v?("PPS:?seq_parameter_set_id"???????????????????,?s);????pps->entropy_coding_mode_flag??????????????=?u_1??("PPS:?entropy_coding_mode_flag"???????????????,?s);??????????????????????????pps->bottom_field_pic_order_in_frame_present_flag????????????????=?u_1??("PPS:?bottom_field_pic_order_in_frame_present_flag"?????????????????,?s);??????pps->num_slice_groups_minus1???????????????=?ue_v?("PPS:?num_slice_groups_minus1"????????????????,?s);??????????if?(pps->num_slice_groups_minus1?>?0)????{??????pps->slice_group_map_type???????????????=?ue_v?("PPS:?slice_group_map_type"????????????????,?s);??????if?(pps->slice_group_map_type?==?0)??????{????????for?(i=0;?i<=pps->num_slice_groups_minus1;?i++)??????????pps->run_length_minus1?[i]??????????????????=?ue_v?("PPS:?run_length_minus1?[i]"??????????????,?s);??????}??????else?if?(pps->slice_group_map_type?==?2)??????{????????for?(i=0;?inum_slice_groups_minus1;?i++)????????{????????????????????pps->top_left?[i]??????????????????????????=?ue_v?("PPS:?top_left?[i]"????????????????????????,?s);??????????pps->bottom_right?[i]??????????????????????=?ue_v?("PPS:?bottom_right?[i]"????????????????????,?s);????????}??????}??????else?if?(pps->slice_group_map_type?==?3?||???????????????pps->slice_group_map_type?==?4?||???????????????pps->slice_group_map_type?==?5)??????{????????pps->slice_group_change_direction_flag?????=?u_1??("PPS:?slice_group_change_direction_flag"??????,?s);????????pps->slice_group_change_rate_minus1????????=?ue_v?("PPS:?slice_group_change_rate_minus1"?????????,?s);??????}??????else?if?(pps->slice_group_map_type?==?6)??????{????????if?(pps->num_slice_groups_minus1+1?>4)??????????NumberBitsPerSliceGroupId?=?3;????????else?if?(pps->num_slice_groups_minus1+1?>?2)??????????NumberBitsPerSliceGroupId?=?2;????????else??????????NumberBitsPerSliceGroupId?=?1;????????pps->pic_size_in_map_units_minus1??????=?ue_v?("PPS:?pic_size_in_map_units_minus1"???????????????,?s);????????if?((pps->slice_group_id?=?calloc?(pps->pic_size_in_map_units_minus1+1,?1))?==?NULL)??????????no_mem_exit?("InterpretPPS:?slice_group_id");????????for?(i=0;?i<=pps->pic_size_in_map_units_minus1;?i++)??????????pps->slice_group_id[i]?=?(byte)?u_v?(NumberBitsPerSliceGroupId,?"slice_group_id[i]",?s);??????}????}????????????pps->num_ref_idx_l0_active_minus1??????????=?ue_v?("PPS:?num_ref_idx_l0_active_minus1"???????????,?s);????pps->num_ref_idx_l1_active_minus1??????????=?ue_v?("PPS:?num_ref_idx_l1_active_minus1"???????????,?s);????pps->weighted_pred_flag????????????????????=?u_1??("PPS:?weighted_pred_flag"?????????????????????,?s);????pps->weighted_bipred_idc???????????????????=?u_v??(?2,?"PPS:?weighted_bipred_idc"????????????????,?s);????pps->pic_init_qp_minus26???????????????????=?se_v?("PPS:?pic_init_qp_minus26"????????????????????,?s);????pps->pic_init_qs_minus26???????????????????=?se_v?("PPS:?pic_init_qs_minus26"????????????????????,?s);??????pps->chroma_qp_index_offset????????????????=?se_v?("PPS:?chroma_qp_index_offset"?????????????????,?s);??????pps->deblocking_filter_control_present_flag?=?u_1?("PPS:?deblocking_filter_control_present_flag"?,?s);????pps->constrained_intra_pred_flag???????????=?u_1??("PPS:?constrained_intra_pred_flag"????????????,?s);????pps->redundant_pic_cnt_present_flag????????=?u_1??("PPS:?redundant_pic_cnt_present_flag"?????????,?s);??????if(more_rbsp_data(s->streamBuffer,?s->frame_bitoffset,s->bitstream_length))?????{????????????pps->transform_8x8_mode_flag???????????=?u_1??("PPS:?transform_8x8_mode_flag"????????????????,?s);??????pps->pic_scaling_matrix_present_flag???=??u_1??("PPS:?pic_scaling_matrix_present_flag"????????,?s);????????if(pps->pic_scaling_matrix_present_flag)??????{????????chroma_format_idc?=?p_Vid->SeqParSet[pps->seq_parameter_set_id].chroma_format_idc;????????n_ScalingList?=?6?+?((chroma_format_idc?!=?YUV444)???2?:?6)?*?pps->transform_8x8_mode_flag;????????for(i=0;?ipic_scaling_list_present_flag[i]=?u_1??("PPS:?pic_scaling_list_present_flag"??????????,?s);????????????if(pps->pic_scaling_list_present_flag[i])??????????{????????????if(i<6)?scaling_list="">ScalingList4x4[i],?16,?&pps->UseDefaultScalingMatrix4x4Flag[i],?s);????????????else??????????????Scaling_List(pps->ScalingList8x8[i-6],?64,?&pps->UseDefaultScalingMatrix8x8Flag[i-6],?s);??????????}????????}??????}??????pps->second_chroma_qp_index_offset??????=?se_v?("PPS:?second_chroma_qp_index_offset"??????????,?s);????}????else????{??????pps->second_chroma_qp_index_offset??????=?pps->chroma_qp_index_offset;????}??????pps->Valid?=?TRUE;????return?p_Dec->UsedBits;??}??
H.264碼流第三個 NALU 是 IDR（即時解碼器刷新）
對應H264標準文檔 7.3.3 序列參數集的語法進行解析
IDR參數解析 [cpp] view plaincopy
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);????????????????????????????????????????????????????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();??????????}??????????????????????????????????????????????????????????if(expected_slice_type?!=?NALU_TYPE_DPA)??????????{????????????????????????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();??????????}??????????????????????if?(img->MbaffFrameFlag)????????????img->current_mb_nr?=?currSlice->start_mb_nr?<<?1=""?style="color:?#0000ff">else??????????????img->current_mb_nr?=?currSlice->start_mb_nr;??????????????????????????????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);??????????}????????????break;????????case?NALU_TYPE_DPB:??????????????????????currStream?????????????=?currSlice->partArr[1].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_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;????????????????????????????????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);??????????????????????}????????????????????????????????????????????break;??
IDR參數解析/*!
[cpp] view plaincopy
<pre?name="code"?class="cpp">?************************************************************************???*?/brief???*????read?the?first?part?of?the?header?(only?the?pic_parameter_set_id)???*?/return???*????Length?of?the?first?part?of?the?slice?header?(in?bits)???************************************************************************???*/????int?FirstPartOfSliceHeader()??{????Slice?*currSlice?=?img->currentSlice;????int?dP_nr?=?assignSE2partition[currSlice->dp_mode][SE_HEADER];????DataPartition?*partition?=?&(currSlice->partArr[dP_nr]);????Bitstream?*currStream?=?partition->bitstream;????int?tmp;??????UsedBits=?partition->bitstream->frame_bitoffset;???????????currSlice->start_mb_nr?=?ue_v?("SH:?first_mb_in_slice",?currStream);??????tmp?=?ue_v?("SH:?slice_type",?currStream);????????if?(tmp>4)?tmp?-=5;??????img->type?=?currSlice->picture_type?=?(SliceType)?tmp;??????currSlice->pic_parameter_set_id?=?ue_v?("SH:?pic_parameter_set_id",?currStream);????????return?UsedBits;??}??</pre><br><br>?
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