有时候来一个RTP包数据，是FU模式打包，没有起始码，我们使用工具无法进行参数解析，
下边提供一个代码用来进行SPS参数解析；
#include <iostream> #pragma once #include<string.h> #include<stdio.h> typedef unsigned char* LPBYTE; typedef unsigned char uint8; typedef unsigned short uint16; typedef unsigned long uint32; typedef unsigned __int64 uint64; typedef signed char int8; typedef signed short int16; typedef signed long int32; typedef signed __int64 int64; struct vc_params_t { int width, height; int profile, level; int nal_length_size; void clear() { memset(this, 0, sizeof(*this)); } }; class NALBitstream { public: NALBitstream() : m_data(NULL), m_len(0), m_idx(0), m_bits(0), m_byte(0), m_zeros(0) {}; NALBitstream(void* data, int len) { Init(data, len); }; void Init(void* data, int len) { m_data = (LPBYTE)data; m_len = len; m_idx = 0; m_bits = 0; m_byte = 0; m_zeros = 0; }; uint8 GetBYTE() { if (m_idx >= m_len) return 0; uint8 b = m_data[m_idx++]; // to avoid start-code emulation, a byte 0x03 is inserted // after any 00 00 pair. Discard that here. if (b == 0) { m_zeros++; if ((m_idx < m_len) && (m_zeros == 2) && (m_data[m_idx] == 0x03)) { m_idx++; m_zeros = 0; } } else { m_zeros = 0; } return b; }; uint32 GetBit() { if (m_bits == 0) { m_byte = GetBYTE(); m_bits = 8; } m_bits--; return (m_byte >> m_bits) & 0x1; }; uint32 GetWord(int bits) { uint32 u = 0; while (bits > 0) { u <<= 1; u |= GetBit(); bits--; } return u; }; uint32 GetUE() { // Exp-Golomb entropy coding: leading zeros, then a one, then // the data bits. The number of leading zeros is the number of // data bits, counting up from that number of 1s as the base. // That is, if you see // 0001010 // You have three leading zeros, so there are three data bits (010) // counting up from a base of 111: thus 111 + 010 = 1001 = 9 int zeros = 0; while (m_idx < m_len && GetBit() == 0) zeros++; return GetWord(zeros) + ((1 << zeros) - 1); }; int32 GetSE() { // same as UE but signed. // basically the unsigned numbers are used as codes to indicate signed numbers in pairs // in increasing value. Thus the encoded values // 0, 1, 2, 3, 4 // mean // 0, 1, -1, 2, -2 etc uint32 UE = GetUE(); bool positive = UE & 1; int32 SE = (UE + 1) >> 1; if (!positive) { SE = -SE; } return SE; }; private: LPBYTE m_data; int m_len; int m_idx; int m_bits; uint8 m_byte; int m_zeros; }; bool ParseSequenceParameterSet(uint8* data, int size, vc_params_t& params) { if (size < 20) { return false; } NALBitstream bs(data, size); // seq_parameter_set_rbsp() bs.GetWord(4);// sps_video_parameter_set_id int sps_max_sub_layers_minus1 = bs.GetWord(3); // "The value of sps_max_sub_layers_minus1 shall be in the range of 0 to 6, inclusive." if (sps_max_sub_layers_minus1 > 6) { return false; } bs.GetWord(1);// sps_temporal_id_nesting_flag // profile_tier_level( sps_max_sub_layers_minus1 ) { bs.GetWord(2);// general_profile_space bs.GetWord(1);// general_tier_flag params.profile = bs.GetWord(5);// general_profile_idc bs.GetWord(32);// general_profile_compatibility_flag[32] bs.GetWord(1);// general_progressive_source_flag bs.GetWord(1);// general_interlaced_source_flag bs.GetWord(1);// general_non_packed_constraint_flag bs.GetWord(1);// general_frame_only_constraint_flag bs.GetWord(44);// general_reserved_zero_44bits params.level = bs.GetWord(8);// general_level_idc uint8 sub_layer_profile_present_flag[6] = { 0 }; uint8 sub_layer_level_present_flag[6] = { 0 }; for (int i = 0; i < sps_max_sub_layers_minus1; i++) { sub_layer_profile_present_flag[i] = bs.GetWord(1); sub_layer_level_present_flag[i] = bs.GetWord(1); } if (sps_max_sub_layers_minus1 > 0) { for (int i = sps_max_sub_layers_minus1; i < 8; i++) { uint8 reserved_zero_2bits = bs.GetWord(2); } } for (int i = 0; i < sps_max_sub_layers_minus1; i++) { if (sub_layer_profile_present_flag[i]) { bs.GetWord(2);// sub_layer_profile_space[i] bs.GetWord(1);// sub_layer_tier_flag[i] bs.GetWord(5);// sub_layer_profile_idc[i] bs.GetWord(32);// sub_layer_profile_compatibility_flag[i][32] bs.GetWord(1);// sub_layer_progressive_source_flag[i] bs.GetWord(1);// sub_layer_interlaced_source_flag[i] bs.GetWord(1);// sub_layer_non_packed_constraint_flag[i] bs.GetWord(1);// sub_layer_frame_only_constraint_flag[i] bs.GetWord(44);// sub_layer_reserved_zero_44bits[i] } if (sub_layer_level_present_flag[i]) { bs.GetWord(8);// sub_layer_level_idc[i] } } } uint32 sps_seq_parameter_set_id = bs.GetUE(); // "The value of sps_seq_parameter_set_id shall be in the range of 0 to 15, inclusive." if (sps_seq_parameter_set_id > 15) { return false; } uint32 chroma_format_idc = bs.GetUE(); // "The value of chroma_format_idc shall be in the range of 0 to 3, inclusive." if (sps_seq_parameter_set_id > 3) { return false; } if (chroma_format_idc == 3) { bs.GetWord(1);// separate_colour_plane_flag } params.width = bs.GetUE(); // pic_width_in_luma_samples params.height = bs.GetUE(); // pic_height_in_luma_samples if (bs.GetWord(1)) {// conformance_window_flag bs.GetUE(); // conf_win_left_offset bs.GetUE(); // conf_win_right_offset bs.GetUE(); // conf_win_top_offset bs.GetUE(); // conf_win_bottom_offset } uint32 bit_depth_luma_minus8 = bs.GetUE(); uint32 bit_depth_chroma_minus8 = bs.GetUE(); if (bit_depth_luma_minus8 != bit_depth_chroma_minus8) { return false; } return true; } int main() { vc_params_t params = { 0 };
//将PPS数据以16进制送进程序 uint8 Sps[] = { 0x42, 0x01, 0x01 ,0x01 ,0x40 ,0x00 ,0x00 ,0x03 ,0x00, 0x00 ,0x03 ,0x00 ,0x00 ,0x03 ,0x00 ,0x00 ,0x03 ,0x00 ,0x5D ,0xA0 ,0x02 ,0x80 ,0x80 ,0x2E ,0x1F ,0x13 ,0x96 ,0xBB ,0x90 ,0x84 ,0x64 ,0xB8 ,0x9A ,0x80 ,0x00 ,0x02 ,0x82 ,0x00 ,0x00 ,0x03 ,0x00 ,0x02,0x00 ,0x00 ,0x03 ,0x00 ,0x28 ,0x10 ,0x24 ,0x00 ,0x00 ,0x13 ,0x80 ,0x60 ,0x00 ,0x02 ,0x8A ,0x0B ,0x96 ,0x2E ,0x00 ,0x00 ,0x00 ,0x02 }; ParseSequenceParameterSet(Sps, 64, params); printf("%d-%d-%d\n", params.width, params.height, params.level);
//我上边的数据得到的宽高是720P system("pause"); return 0; }
