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H264码流解析（三）：解析SPS和PPS_sps pps 解析

作者：小丑西瓜9 | 2024-06-01 22:27:56

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sps pps 解析

上两篇里面写了划分NALU和指数哥伦布编码，这一篇主要写解析SPS和PPS。

1、下载bs.h头文件

下载bs.h头文件，并在项目中使用

下载地址

2、解析SPS

H264官方文档英文版下载

先看SPS（序列参数集）的结构，再7.3.2.1.1里面包含了SPS结构的介绍

 其中scaling_list函数在7.3.2.1.1.1里，如图所示

vui_parameters函数在E1.1里 ，如图所示

hrd_parameters()函数在E.1.2里面，如图 

具体代码如下，注意点就是我们要将EBSP的数据转变为RBSP的数据才可以解析，不然系欸小会有问题

  1. #define Extended_SAR 255
  2. bs_t* b;
  3. void scaling_list(uint32_t* scalingList, int sizeOfScalingList, uint32_t useDefaultScalingMatrixFlag) {
  4. 	int lastScale = 8;
  5. 	int nextScale = 8;
  6. 	for (int j = 0; j < sizeOfScalingList; j++) {
  7. 		if (nextScale != 0) {
  8. 			int delta_scale = bs_read_se(b);
  9. 			std::cout << "delta_scale:" << delta_scale << std::endl;
  10. 			nextScale = (lastScale + delta_scale + 256) % 256;
  11. 			useDefaultScalingMatrixFlag = (j == 0 && nextScale  == 0);
  12. 		}
  13. 		scalingList[j] = (nextScale == 0) ? lastScale : nextScale;
  14. 		lastScale = scalingList[j];
  15. 	}
  16. }
  17.  
  18. void hrd_parameters() {
  19. 	std::cout << "==hrd==" << std::endl;
  20. 	uint32_t cpb_cnt_minus1 = bs_read_ue(b);
  21. 	std::cout << "cpb_cnt_minus1:" << cpb_cnt_minus1 << std::endl;
  22. 	std::cout << "bit_rate_scale:" << bs_read_u(b, 4) << std::endl;
  23. 	std::cout << "cpb_size_scale:" << bs_read_u(b, 4) << std::endl;
  24. 	uint32_t bit_rate_value_minus1[5];
  25. 	uint32_t cpb_size_value_minus1[5];
  26. 	uint32_t cbr_flag[5];
  27. 	for (int SchedSelIdx = 0; SchedSelIdx <= cpb_cnt_minus1; SchedSelIdx++) {
  28. 		bit_rate_value_minus1[SchedSelIdx] = bs_read_ue(b);
  29. 		cpb_size_value_minus1[SchedSelIdx] = bs_read_ue(b);
  30. 		cbr_flag[SchedSelIdx] = bs_read_u1(b);
  31. 	}
  32. 	std::cout << "initial_cpb_removal_delay_length_minus1:" << bs_read_u(b, 5) << std::endl;
  33. 	std::cout << "cpb_removal_delay_length_minus1:" << bs_read_u(b, 5) << std::endl;
  34. 	std::cout << "dpb_output_delay_length_minus1:" << bs_read_u(b, 5) << std::endl;
  35. 	std::cout << "time_offset_length:" << bs_read_u(b, 5) << std::endl;
  36. 	std::cout << "==hrd end==" << std::endl;
  37. }
  38.  
  39. void vui_parameters() {
  40. 	std::cout << "==VUI==" << std::endl;
  41. 	uint32_t aspect_ratio_info_present_flag = bs_read_u1(b);
  42. 	std::cout << "aspect_ratio_info_present_flag:" << aspect_ratio_info_present_flag << std::endl;
  43. 	if (aspect_ratio_info_present_flag) {
  44. 		uint32_t aspect_ratio_idc = bs_read_u8(b);
  45. 		std::cout << "  aspect_ratio_idc:" << aspect_ratio_idc << std::endl;
  46. 		if (aspect_ratio_idc == Extended_SAR){
  47. 			std::cout << "    sar_width:" << bs_read_u(b,16);
  48. 			std::cout << "    sar_height:" << bs_read_u(b, 16);
  49. 		}
  50. 	}
  51. 	uint32_t overscan_info_present_flag = bs_read_u1(b);
  52. 	std::cout << "overscan_info_present_flag:" << overscan_info_present_flag << std::endl;
  53. 	if (overscan_info_present_flag) {
  54. 		std::cout << "  overscan_appropriate_flag:" << bs_read_u1(b) << std::endl;
  55. 	}
  56. 	uint32_t video_signal_type_present_flag = bs_read_u1(b);
  57. 	std::cout << "video_signal_type_present_flag:" << video_signal_type_present_flag << std::endl;
  58. 	if (video_signal_type_present_flag) {
  59. 		std::cout << "  video_format:" << bs_read_u(b,3) << std::endl;
  60. 		std::cout << "  video_full_range_flag:" << bs_read_u1(b) << std::endl;
  61. 		uint32_t colour_description_present_flag = bs_read_u1(b);
  62. 		std::cout << "  colour_description_present_flag:" << colour_description_present_flag << std::endl;
  63. 		if (colour_description_present_flag) {
  64. 			std::cout << "    colour_primaries:" << bs_read_u8(b) << std::endl;
  65. 			std::cout << "    transfer_characteristics:" << bs_read_u8(b) << std::endl;
  66. 			std::cout << "    matrix_coefficients:" << bs_read_u8(b) << std::endl;
  67. 		}
  68. 	}
  69. 	uint32_t chroma_loc_info_present_flag = bs_read_u1(b);
  70. 	std::cout << "chroma_loc_info_present_flag:" << chroma_loc_info_present_flag << std::endl;
  71. 	if (chroma_loc_info_present_flag) {
  72. 		std::cout << "  chroma_sample_loc_type_top_field:" << bs_read_ue(b) << std::endl;
  73. 		std::cout << "  chroma_sample_loc_type_bottom_field:" << bs_read_ue(b) << std::endl;
  74. 	}
  75. 	uint32_t timing_info_present_flag = bs_read_u1(b);
  76. 	std::cout << "timing_info_present_flag:" << timing_info_present_flag << std::endl;
  77. 	if (timing_info_present_flag) {
  78. 		std::cout << "  num_units_in_tick:" << bs_read_u(b, 32) << std::endl;
  79. 		std::cout << "  time_scale:" << bs_read_u(b, 32) << std::endl;
  80. 		std::cout << "  fixed_frame_rate_flag:" << bs_read_u1(b) << std::endl;
  81. 	}
  82. 	uint32_t nal_hrd_parameters_present_flag = bs_read_u1(b);
  83. 	std::cout << "nal_hrd_parameters_present_flag:" << nal_hrd_parameters_present_flag << std::endl;
  84. 	if (nal_hrd_parameters_present_flag) {
  85. 		hrd_parameters();
  86. 	}
  87. 	uint32_t vcl_hrd_parameters_present_flag = bs_read_u1(b);
  88. 	std::cout << "vcl_hrd_parameters_present_flag:" << vcl_hrd_parameters_present_flag << std::endl;
  89. 	if (vcl_hrd_parameters_present_flag) {
  90. 		hrd_parameters();
  91. 	}
  92. 	if (nal_hrd_parameters_present_flag || vcl_hrd_parameters_present_flag) {
  93. 		std::cout << "  low_delay_hrd_flag:" << bs_read_u1(b) << std::endl;
  94. 	}
  95. 	std::cout << "pic_struct_present_flag:" << bs_read_u1(b) << std::endl;
  96. 	uint32_t bitstream_restriction_flag = bs_read_u1(b);
  97. 	std::cout << "bitstream_restriction_flag:" << bitstream_restriction_flag << std::endl;
  98. 	if (bitstream_restriction_flag) {
  99. 		std::cout << "  motion_vectors_over_pic_boundaries_flag:" << bs_read_u1(b) << std::endl;
  100. 		std::cout << "  max_bytes_per_pic_denom:" << bs_read_ue(b) << std::endl;
  101. 		std::cout << "  max_bits_per_mb_denom:" << bs_read_ue(b) << std::endl;
  102. 		std::cout << "  log2_max_mv_length_horizontal:" << bs_read_ue(b) << std::endl;
  103. 		std::cout << "  log2_max_mv_length_vertical:" << bs_read_ue(b) << std::endl;
  104. 		std::cout << "  num_reorder_frames:" << bs_read_ue(b) << std::endl;
  105. 		std::cout << "  max_dec_frame_buffering:" << bs_read_ue(b) << std::endl;
  106. 	}
  107. 	std::cout << "==VUI== End" << std::endl;
  108. }
  109.  
  110. std::vector<uint8_t> EBSP2RBSP(uint8_t* buffer, int len) {
  111. 	// 00 00 03 去掉03
  112. 	std::vector<uint8_t> ebsp;
  113. 	int i = 0;
  114. 	for (i = 0; i < len-2; ++i) {
  115. 		if (buffer[i] == 0x00 && buffer[i+1] == 0x00 && buffer[i+2] == 0x03) {
  116. 			ebsp.push_back(buffer[i++]);
  117. 			ebsp.push_back(buffer[i++]);
  118. 		}
  119. 		else {
  120. 			ebsp.push_back(buffer[i]);
  121. 		}
  122. 	}
  123. 	for (; i < len; ++i) {
  124. 		ebsp.push_back(buffer[i]);
  125. 	}
  126. 	return ebsp;
  127. }
  128. uint32_t chroma_format_idc; // pps要使用
  129. void ParseSPS(uint8_t* buffer, int len) {
  130. 	std::vector<uint8_t> ebsp = EBSP2RBSP(buffer, len);
  131. 	b = bs_new(ebsp.data(), ebsp.size());
  132. 	
  133. 	std::cout << "forbidden_zero_bit :" << bs_read_u(b, 1) << std::endl;
  134. 	std::cout << "nal_ref_idc:" << bs_read_u(b, 2) << std::endl;
  135. 	std::cout << "nal_unit_type:" << bs_read_u(b, 5) << std::endl;
  136. 	uint32_t profile_idc = bs_read_u8(b);
  137. 	std::cout << "profile_idc:" << profile_idc << std::endl;
  138. 	std::cout << "constraint_set0_flag:" << bs_read_u(b, 1) << std::endl;
  139. 	std::cout << "constraint_set1_flag:" << bs_read_u(b, 1) << std::endl;
  140. 	std::cout << "constraint_set2_flag:" << bs_read_u(b, 1) << std::endl;
  141. 	std::cout << "constraint_set3_flag:" << bs_read_u(b, 1) << std::endl;
  142. 	std::cout << "constraint_set4_flag:" << bs_read_u(b, 1) << std::endl;
  143. 	std::cout << "constraint_set5_flag:" << bs_read_u(b, 1) << std::endl;
  144. 	std::cout << "reserved_zero_2bits :" << bs_read_u(b, 2) << std::endl;
  145. 	std::cout << "level_idc:" << bs_read_u8(b) << std::endl;
  146. 	std::cout << "seq_parameter_set_id:" << bs_read_ue(b) << std::endl;
  147. 	if (profile_idc == 100 || profile_idc == 110 || profile_idc == 122 ||
  148. 		profile_idc == 244 || profile_idc == 44 || profile_idc == 83 ||
  149. 		profile_idc == 86 || profile_idc == 118 || profile_idc == 128) {
  150. 		chroma_format_idc = bs_read_ue(b);
  151. 		std::cout << "  chroma_format_idc:" << chroma_format_idc << std::endl;
  152. 		if (chroma_format_idc == 3) {
  153. 			std::cout << "  separate_colour_plane_flag:" << bs_read_u(b, 1) << std::endl;
  154. 		}
  155. 		std::cout << "  bit_depth_luma_minus8:" << bs_read_ue(b) << std::endl;
  156. 		std::cout << "  bit_depth_chroma_minus8:" << bs_read_ue(b) << std::endl;
  157. 		std::cout << "  qpprime_y_zero_transform_bypass_flag:" << bs_read_u(b, 1) << std::endl;
  158. 		uint32_t seq_scaling_matrix_present_flag = bs_read_u(b, 1);
  159. 		std::cout << "  seq_scaling_matrix_present_flag:" << seq_scaling_matrix_present_flag << std::endl;
  160. 		
  161. 		if (seq_scaling_matrix_present_flag) {
  162. 			uint32_t seq_scaling_list_present_flag[12];
  163. 			uint32_t* ScalingList4x4[12];
  164. 			uint32_t UseDefaultScalingMatrix4x4Flag[12];
  165. 			uint32_t* ScalingList8x8[12];
  166. 			uint32_t UseDefaultScalingMatrix8x8Flag[12];
  167. 			for (int i = 0; i < ((chroma_format_idc != 3) ? 8 : 12); i++) {
  168. 				seq_scaling_list_present_flag[i] = bs_read_u(b, 1);
  169. 				if (seq_scaling_list_present_flag[i]) {
  170. 					if (i < 6) {
  171. 						scaling_list(ScalingList4x4[i], 16,
  172. 							UseDefaultScalingMatrix4x4Flag[i]);
  173. 					}
  174. 					else {
  175. 						scaling_list(ScalingList8x8[i-6], 64,
  176. 							UseDefaultScalingMatrix8x8Flag[i-6]);
  177. 					}
  178. 				}
  179. 			}
  180. 		}
  181. 	}
  182. 	std::cout << "log2_max_frame_num_minus4:" << bs_read_ue(b) << std::endl;
  183. 	uint32_t pic_order_cnt_type = bs_read_ue(b);
  184. 	std::cout << "pic_order_cnt_type:" << pic_order_cnt_type << std::endl;
  185. 	if (pic_order_cnt_type == 0) {
  186. 		std::cout << "  log2_max_pic_order_cnt_lsb_minus4:" << bs_read_ue(b) << std::endl;
  187. 	}
  188. 	else if (pic_order_cnt_type == 1) {
  189. 		std::cout << "  delta_pic_order_always_zero_flag:" << bs_read_u(b, 1) << std::endl;
  190. 		std::cout << "  offset_for_non_ref_pic:" << bs_read_se(b) << std::endl;
  191. 		std::cout << "  offset_for_top_to_bottom_field:" << bs_read_se(b) << std::endl;
  192. 		uint32_t num_ref_frames_in_pic_order_cnt_cycle = bs_read_ue(b);
  193. 		std::cout << "  num_ref_frames_in_pic_order_cnt_cycle:" << num_ref_frames_in_pic_order_cnt_cycle << std::endl;
  194. 		int offset_for_ref_frame[256];
  195. 		for (int i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++) {
  196. 			offset_for_ref_frame[i] = bs_read_se(b);
  197. 		}
  198. 	}
  199. 	std::cout << "max_num_ref_frames:" << bs_read_ue(b) << std::endl;
  200. 	std::cout << "gaps_in_frame_num_value_allowed_flag:" << bs_read_u(b,1) << std::endl;
  201. 	std::cout << "pic_width_in_mbs_minus1:" << bs_read_ue(b) << std::endl;
  202. 	std::cout << "pic_height_in_map_units_minus1:" << bs_read_ue(b) << std::endl;
  203. 	uint32_t frame_mbs_only_flag = bs_read_u(b, 1);
  204. 	std::cout << "frame_mbs_only_flag:" << frame_mbs_only_flag << std::endl;
  205. 	if (!frame_mbs_only_flag) {
  206. 		std::cout << "  mb_adaptive_frame_field_flag:" << bs_read_u(b, 1) << std::endl;
  207. 	}
  208. 	std::cout << "direct_8x8_inference_flag:" << bs_read_u(b, 1) << std::endl;
  209. 	uint32_t frame_cropping_flag = bs_read_u(b, 1);
  210. 	std::cout << "frame_cropping_flag:" << frame_cropping_flag << std::endl;
  211. 	if (frame_cropping_flag) {
  212. 		std::cout << "  frame_crop_left_offset:" << bs_read_ue(b) << std::endl;
  213. 		std::cout << "  frame_crop_right_offset:" << bs_read_ue(b) << std::endl;
  214. 		std::cout << "  frame_crop_top_offset:" << bs_read_ue(b) << std::endl;
  215. 		std::cout << "  frame_crop_bottom_offset:" << bs_read_ue(b) << std::endl;
  216. 	}
  217. 	uint32_t vui_parameters_present_flag = bs_read_u(b, 1);
  218. 	std::cout << "vui_parameters_present_flag:" << vui_parameters_present_flag << std::endl;
  219. 	if (vui_parameters_present_flag) {
  220. 		vui_parameters();
  221. 	}
  222. 	bs_free(b);
  223. }

 通过解析我们可以发现SPS序列参数集里面包含以下内容：

（1）、profile_idc，指明所需要的profile

（2）、level_idc，指明所需要的level

（3）、sps的id，后面pps根据sps的id找到对应的sps

（4）、max_num_ref_frames用于参考帧的最大数目

（5）、图像的宽pic_width_in_mbs_minus1和高pic_height_in_map_units_minus1，计算方法width = （pic_width_in_mbs_minus1+1）*16 。height = (pic_height_in_map_units_minus1+1)*16

（6）、video_full_range_flag ，表示video range还是full fange

（7）、帧速率，每一帧之间的间隔

（8）、 frame_mbs_only_flag，宏块编码方式，为1表示所有宏块都是用帧编码，为0表示可能使用帧编码也可能使用场编码

（9）、log2_max_pic_order_cnt_lsb_minus4，表示POC的上限

（10）、pic_order_cnt_type，指明poc的编码方式，poc标识图像的播放顺序

等等

具体可以参考下面两篇文章

H264___sps_pps___分析_郭风朴(guofengpu)的Android影音专栏-CSDN博客

H264参数结构三：序列参数集层（SPS） &　图像参数集语义_heanyu的专栏-CSDN博客

3、解析PPS

PPS：图像参数集，具体内容如下

具体代码如下所示

  1. // 一个bit 1，若干个bit 0
  2. void rbsp_trailing_bits() {
  3. 		int rbsp_stop_one_bit = bs_read_u1(b); // equal to 1
  4. 		std::cout << "rbsp_stop_one_bit:" << rbsp_stop_one_bit << std::endl;
  5. 		while (!bs_byte_aligned(b)){
  6. 			int rbsp_alignment_zero_bit = bs_read_u1(b); // equal to 0
  7. 		}
  8. }
  9.  
  10. // 是不是有更多的RBSP数据
  11. uint32_t more_rbsp_data() {
  12. 	if (bs_eof(b)) { return 0; }
  13. 	if (bs_peek_u1(b) == 1) { return 0; } // if next bit is 1, we've reached the stop bit
  14. 	return 1;
  15. }
  16.  
  17. void ParsePPS(uint8_t* buffer, int len) {
  18. 	std::cout << "=========================PPS=======================" << std::endl;
  19. 	std::vector<uint8_t> ebsp = EBSP2RBSP(buffer, len);
  20. 	// std::cout << "pps buffer len:" << ebsp.size() << std::endl;
  21. 	b = bs_new(ebsp.data(), ebsp.size());
  22. 	std::cout << "forbidden_zero_bit :" << bs_read_u(b, 1) << std::endl;
  23. 	std::cout << "nal_ref_idc:" << bs_read_u(b, 2) << std::endl;
  24. 	std::cout << "nal_unit_type:" << bs_read_u(b, 5) << std::endl;
  25. 	std::cout << "pic_parameter_set_id:" << bs_read_ue(b) << std::endl;
  26. 	std::cout << "seq_parameter_set_id:" << bs_read_ue(b) << std::endl;
  27. 	std::cout << "entropy_coding_mode_flag:" << bs_read_u1(b) << std::endl;
  28. 	std::cout << "bottom_field_pic_order_in_frame_present_flag:" << bs_read_u1(b) << std::endl;
  29. 	uint32_t num_slice_groups_minus1 = bs_read_ue(b);
  30. 	std::cout << "num_slice_groups_minus1:" << num_slice_groups_minus1 << std::endl;
  31. 	if (num_slice_groups_minus1 > 0) {
  32. 		uint32_t slice_group_map_type = bs_read_ue(b);
  33. 		std::cout << "  slice_group_map_type:" << slice_group_map_type << std::endl;
  34. 		if (slice_group_map_type == 0) {
  35. 			uint32_t run_length_minus1[8];
  36. 			for (int iGroup = 0; iGroup <= num_slice_groups_minus1; iGroup++) {
  37. 				run_length_minus1[iGroup] = bs_read_ue(b);
  38. 			}
  39. 		}
  40. 		else if (slice_group_map_type == 2) {
  41. 			uint32_t top_left[8];
  42. 			uint32_t bottom_right[8];
  43. 			for (int iGroup = 0; iGroup < num_slice_groups_minus1; iGroup++) {
  44. 				top_left[iGroup] = bs_read_ue(b);
  45. 				bottom_right[iGroup] = bs_read_ue(b);
  46. 			}
  47. 		}
  48. 		else if (slice_group_map_type == 3 ||
  49. 			slice_group_map_type == 4 ||
  50. 			slice_group_map_type == 5) {
  51. 			std::cout << "    slice_group_change_direction_flag:" << bs_read_u1(b) << std::endl;
  52. 			std::cout << "    slice_group_change_rate_minus1:" << bs_read_ue(b) << std::endl;
  53. 		}
  54. 		else if (slice_group_map_type == 6) {
  55. 			uint32_t pic_size_in_map_units_minus1 = bs_read_ue(b);
  56. 			std::cout << "    pic_size_in_map_units_minus1:" << pic_size_in_map_units_minus1 << std::endl;
  57. 			uint32_t slice_group_id[8];
  58. 			for (int i = 0; i <= pic_size_in_map_units_minus1; i++) {
  59. 				slice_group_id[i] = bs_read_ue(b);
  60. 			}
  61. 		}
  62. 	}
  63. 	std::cout << "num_ref_idx_l0_default_active_minus1:" << bs_read_ue(b) << std::endl;
  64. 	std::cout << "num_ref_idx_l1_default_active_minus1:" << bs_read_ue(b) << std::endl;
  65. 	std::cout << "weighted_pred_flag:" << bs_read_u1(b) << std::endl;
  66. 	std::cout << "weighted_bipred_idc:" << bs_read_u(b,2) << std::endl;
  67. 	std::cout << "pic_init_qp_minus26:" << bs_read_se(b) << std::endl;
  68. 	std::cout << "pic_init_qs_minus26:" << bs_read_se(b) << std::endl;
  69. 	std::cout << "chroma_qp_index_offset:" << bs_read_se(b) << std::endl;
  70. 	std::cout << "deblocking_filter_control_present_flag:" << bs_read_u1(b) << std::endl;
  71. 	std::cout << "constrained_intra_pred_flag:" << bs_read_u1(b) << std::endl;
  72. 	std::cout << "redundant_pic_cnt_present_flag:" << bs_read_u1(b) << std::endl;
  73. 	if (more_rbsp_data()) {
  74. 		uint32_t transform_8x8_mode_flag = bs_read_u1(b);
  75. 		std::cout << "  transform_8x8_mode_flag:" << transform_8x8_mode_flag << std::endl;
  76. 		uint32_t pic_scaling_matrix_present_flag = bs_read_u1(b);
  77. 		std::cout << "  pic_scaling_matrix_present_flag:" << std::endl;
  78. 		uint32_t pic_scaling_list_present_flag[6];
  79. 		uint32_t* ScalingList4x4[12];
  80. 		uint32_t UseDefaultScalingMatrix4x4Flag[12];
  81. 		uint32_t* ScalingList8x8[12];
  82. 		uint32_t UseDefaultScalingMatrix8x8Flag[12];
  83. 		if (pic_scaling_matrix_present_flag) {
  84. 			for (int i = 0; i < 6 + ((chroma_format_idc != 3) ? 2 : 6) * transform_8x8_mode_flag; i++) {
  85. 				pic_scaling_list_present_flag[i] = bs_read_u1(b);
  86. 				if (pic_scaling_list_present_flag[i]) {
  87. 					if (i < 6) {
  88. 						scaling_list(ScalingList4x4[i], 16,
  89. 							UseDefaultScalingMatrix4x4Flag[i]);
  90. 					}
  91. 					else {
  92. 						scaling_list(ScalingList8x8[i - 6], 64,
  93. 							UseDefaultScalingMatrix8x8Flag[i - 6]);
  94. 					}
  95. 				}
  96. 			}
  97. 		}
  98. 		std::cout << "  second_chroma_qp_index_offset:" << bs_read_se(b) << std::endl;
  99. 	}
  100. 	rbsp_trailing_bits();
  101. 	bs_free(b);
  102. }

 PPS里面主要包含以下内容

（1）、PPS的id

（2）、SPS的id

（3）、entropy_coding_mode_flag 熵编码的选择，为0表示使用CAVLC，为表示CABAC

（4）、num_slice_groups_minus1，加1表示图像中使用片组的个数

等等

当然，我们也可以不适用bs.h头文件，也可以自己写解析过程，主要就是bs_read_u1,bs_read_u,bs_read_u8,bs_read_ue,bs_read_se这几个函数

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