248 lines
6.6 KiB
C++
248 lines
6.6 KiB
C++
/**
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* Simplest Librtmp Send 264
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*
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* 雷霄骅，张晖
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* leixiaohua1020@126.com
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* zhanghuicuc@gmail.com
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* 中国传媒大学/数字电视技术
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* Communication University of China / Digital TV Technology
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* http://blog.csdn.net/leixiaohua1020
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*
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* 本程序用于将内存中的H.264数据推送至RTMP流媒体服务器。
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*
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*/
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#include "sps_decode.h"
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typedef unsigned int UINT;
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typedef unsigned char BYTE;
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typedef unsigned long DWORD;
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UINT Ue(BYTE *pBuff, UINT nLen, UINT &nStartBit)
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{
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//计算0bit的个数
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UINT nZeroNum = 0;
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while (nStartBit < nLen * 8)
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{
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if (pBuff[nStartBit / 8] & (0x80 >> (nStartBit % 8))) //&:按位与，%取余
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{
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break;
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}
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nZeroNum++;
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nStartBit++;
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}
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nStartBit ++;
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//计算结果
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DWORD dwRet = 0;
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for (UINT i=0; i<nZeroNum; i++)
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{
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dwRet <<= 1;
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if (pBuff[nStartBit / 8] & (0x80 >> (nStartBit % 8)))
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{
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dwRet += 1;
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}
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nStartBit++;
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}
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return (1 << nZeroNum) - 1 + dwRet;
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}
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int Se(BYTE *pBuff, UINT nLen, UINT &nStartBit)
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{
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int UeVal=Ue(pBuff,nLen,nStartBit);
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double k=UeVal;
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int nValue=ceil(k/2);
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//ceil函数：ceil函数的作用是求不小于给定实数的最小整数。ceil(2)=ceil(1.2)=cei(1.5)=2.00
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if (UeVal % 2==0)
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nValue=-nValue;
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return nValue;
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}
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DWORD u(UINT BitCount,BYTE * buf,UINT &nStartBit)
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{
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DWORD dwRet = 0;
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for (UINT i=0; i<BitCount; i++)
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{
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dwRet <<= 1;
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if (buf[nStartBit / 8] & (0x80 >> (nStartBit % 8)))
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{
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dwRet += 1;
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}
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nStartBit++;
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}
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return dwRet;
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}
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/**
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* H264的NAL起始码防竞争机制
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*
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* @param buf SPS数据内容
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*
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* @无返回值
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*/
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void de_emulation_prevention(BYTE* buf,unsigned int* buf_size)
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{
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int i=0,j=0;
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BYTE* tmp_ptr = nullptr;
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unsigned int tmp_buf_size=0;
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int val=0;
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tmp_ptr=buf;
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tmp_buf_size=*buf_size;
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for(i=0;i<(tmp_buf_size-2);i++)
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{
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//check for 0x000003
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val=(tmp_ptr[i]^0x00) +(tmp_ptr[i+1]^0x00)+(tmp_ptr[i+2]^0x03);
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if(val==0)
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{
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//kick out 0x03
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for(j=i+2;j<tmp_buf_size-1;j++)
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tmp_ptr[j]=tmp_ptr[j+1];
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//and so we should devrease bufsize
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(*buf_size)--;
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}
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}
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return;
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}
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/**
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* 解码SPS,获取视频图像宽、高信息
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*
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* @param buf SPS数据内容
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* @param nLen SPS数据的长度
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* @param width 图像宽度
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* @param height 图像高度
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* @成功则返回1 , 失败则返回0
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*/
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int h264_decode_sps(BYTE * buf,unsigned int nLen,int &width,int &height,int &fps)
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{
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UINT StartBit=0;
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fps=0;
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de_emulation_prevention(buf,&nLen);
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int forbidden_zero_bit = u(1,buf,StartBit);
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int nal_ref_idc = u(2,buf,StartBit);
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int nal_unit_type = u(5,buf,StartBit);
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if(nal_unit_type==7)
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{
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int profile_idc=u(8,buf,StartBit);
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int constraint_set0_flag=u(1,buf,StartBit);//(buf[1] & 0x80)>>7;
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int constraint_set1_flag=u(1,buf,StartBit);//(buf[1] & 0x40)>>6;
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int constraint_set2_flag=u(1,buf,StartBit);//(buf[1] & 0x20)>>5;
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int constraint_set3_flag=u(1,buf,StartBit);//(buf[1] & 0x10)>>4;
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int reserved_zero_4bits=u(4,buf,StartBit);
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int level_idc=u(8,buf,StartBit);
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int seq_parameter_set_id=Ue(buf,nLen,StartBit);
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if( profile_idc == 100 || profile_idc == 110 ||
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profile_idc == 122 || profile_idc == 144 )
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{
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int chroma_format_idc=Ue(buf,nLen,StartBit);
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if( chroma_format_idc == 3 )
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int residual_colour_transform_flag=u(1,buf,StartBit);
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int bit_depth_luma_minus8=Ue(buf,nLen,StartBit);
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int bit_depth_chroma_minus8=Ue(buf,nLen,StartBit);
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int qpprime_y_zero_transform_bypass_flag=u(1,buf,StartBit);
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int seq_scaling_matrix_present_flag=u(1,buf,StartBit);
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int seq_scaling_list_present_flag[8];
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if( seq_scaling_matrix_present_flag )
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{
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for( int i = 0; i < 8; i++ ) {
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seq_scaling_list_present_flag[i]=u(1,buf,StartBit);
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}
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}
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}
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int log2_max_frame_num_minus4=Ue(buf,nLen,StartBit);
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int pic_order_cnt_type=Ue(buf,nLen,StartBit);
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if( pic_order_cnt_type == 0 )
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int log2_max_pic_order_cnt_lsb_minus4=Ue(buf,nLen,StartBit);
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else if( pic_order_cnt_type == 1 )
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{
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int delta_pic_order_always_zero_flag=u(1,buf,StartBit);
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int offset_for_non_ref_pic=Se(buf,nLen,StartBit);
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int offset_for_top_to_bottom_field=Se(buf,nLen,StartBit);
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int num_ref_frames_in_pic_order_cnt_cycle=Ue(buf,nLen,StartBit);
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int *offset_for_ref_frame=new int[num_ref_frames_in_pic_order_cnt_cycle];
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for( int i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++ )
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offset_for_ref_frame[i]=Se(buf,nLen,StartBit);
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delete [] offset_for_ref_frame;
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}
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int num_ref_frames=Ue(buf,nLen,StartBit);
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int gaps_in_frame_num_value_allowed_flag=u(1,buf,StartBit);
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int pic_width_in_mbs_minus1=Ue(buf,nLen,StartBit);
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int pic_height_in_map_units_minus1=Ue(buf,nLen,StartBit);
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width=(pic_width_in_mbs_minus1+1)*16;
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height=(pic_height_in_map_units_minus1+1)*16;
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int frame_mbs_only_flag=u(1,buf,StartBit);
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if(!frame_mbs_only_flag)
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int mb_adaptive_frame_field_flag=u(1,buf,StartBit);
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int direct_8x8_inference_flag=u(1,buf,StartBit);
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int frame_cropping_flag=u(1,buf,StartBit);
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if(frame_cropping_flag)
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{
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int frame_crop_left_offset=Ue(buf,nLen,StartBit);
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int frame_crop_right_offset=Ue(buf,nLen,StartBit);
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int frame_crop_top_offset=Ue(buf,nLen,StartBit);
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int frame_crop_bottom_offset=Ue(buf,nLen,StartBit);
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}
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int vui_parameter_present_flag=u(1,buf,StartBit);
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if(vui_parameter_present_flag)
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{
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int aspect_ratio_info_present_flag=u(1,buf,StartBit);
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if(aspect_ratio_info_present_flag)
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{
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int aspect_ratio_idc=u(8,buf,StartBit);
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if(aspect_ratio_idc==255)
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{
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int sar_width=u(16,buf,StartBit);
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int sar_height=u(16,buf,StartBit);
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}
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}
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int overscan_info_present_flag=u(1,buf,StartBit);
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if(overscan_info_present_flag)
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int overscan_appropriate_flagu=u(1,buf,StartBit);
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int video_signal_type_present_flag=u(1,buf,StartBit);
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if(video_signal_type_present_flag)
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{
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int video_format=u(3,buf,StartBit);
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int video_full_range_flag=u(1,buf,StartBit);
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int colour_description_present_flag=u(1,buf,StartBit);
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if(colour_description_present_flag)
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{
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int colour_primaries=u(8,buf,StartBit);
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int transfer_characteristics=u(8,buf,StartBit);
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int matrix_coefficients=u(8,buf,StartBit);
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}
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}
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int chroma_loc_info_present_flag=u(1,buf,StartBit);
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if(chroma_loc_info_present_flag)
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{
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int chroma_sample_loc_type_top_field=Ue(buf,nLen,StartBit);
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int chroma_sample_loc_type_bottom_field=Ue(buf,nLen,StartBit);
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}
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int timing_info_present_flag=u(1,buf,StartBit);
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if(timing_info_present_flag)
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{
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int num_units_in_tick=u(32,buf,StartBit);
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int time_scale=u(32,buf,StartBit);
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fps=time_scale/(2*num_units_in_tick);
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}
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}
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return true;
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}
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else
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return false;
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}
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