获取.h264视频宽高的方法
花了2个通宵终于搞定。（后面附上完整代码）
http://write.blog.csdn.net/postedit/7852406
图像的高和宽在H264的SPS帧中。
在H264码流中，都是以"0x00 0x00 0x01"或者"0x00 0x00 0x00 0x01"为开始码的,找到开始码之后,使用开始码之后的第一个字节的低5位判断是否为7(sps)，等于7表示该帧就是SPS帧，从该帧就可以解析出高和宽，SPS是个结构体，里面有两个成员：pic_width_in_mbs_minus1，pic_height_in_map_units_minus_1，分别表示图像的宽和高，以宏块（16x16）为单位的值减1，因此，实际的宽为 (pic_width_in_mbs_minus1+1)*16，高为 (pic_height_in_map_units_minus_1+1)*16
http://write.blog.csdn.net/postedit/7852406
UINT Ue(BYTE *pBuff, UINT nLen, UINT &nStartBit)
{
//计算0bit的个数
UINT nZeroNum = ;
while (nStartBit < nLen * )
{
if (pBuff[nStartBit / ] & (0x80 >> (nStartBit % ))) //&:按位与，%取余
{
break;
}
nZeroNum++;
nStartBit++;
}
nStartBit ++; //计算结果
DWORD dwRet = ;
for (UINT i=; i<nZeroNum; i++)
{
dwRet <<= ;
if (pBuff[nStartBit / ] & (0x80 >> (nStartBit % )))
{
dwRet += ;
}
nStartBit++;
}
return ( << nZeroNum) - + dwRet;
} int Se(BYTE *pBuff, UINT nLen, UINT &nStartBit)
{ int UeVal=Ue(pBuff,nLen,nStartBit);
double k=UeVal;
int nValue=ceil(k/);//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
if (UeVal % ==)
nValue=-nValue;
return nValue; } DWORD u(UINT BitCount,BYTE * buf,UINT &nStartBit)
{
DWORD dwRet = ;
for (UINT i=; i<BitCount; i++)
{
dwRet <<= ;
if (buf[nStartBit / ] & (0x80 >> (nStartBit % )))
{
dwRet += ;
}
nStartBit++;
}
return dwRet;
} bool h264_decode_seq_parameter_set(BYTE * buf,UINT nLen,int &Width,int &Height)
{
UINT StartBit=;
int forbidden_zero_bit=u(,buf,StartBit);
int nal_ref_idc=u(,buf,StartBit);
int nal_unit_type=u(,buf,StartBit);
if(nal_unit_type==)
{
int profile_idc=u(,buf,StartBit);
int constraint_set0_flag=u(,buf,StartBit);//(buf[1] & 0x80)>>7;
int constraint_set1_flag=u(,buf,StartBit);//(buf[1] & 0x40)>>6;
int constraint_set2_flag=u(,buf,StartBit);//(buf[1] & 0x20)>>5;
int constraint_set3_flag=u(,buf,StartBit);//(buf[1] & 0x10)>>4;
int reserved_zero_4bits=u(,buf,StartBit);
int level_idc=u(,buf,StartBit); int seq_parameter_set_id=Ue(buf,nLen,StartBit); if( profile_idc == || profile_idc == ||
profile_idc == || profile_idc == )
{
int chroma_format_idc=Ue(buf,nLen,StartBit);
if( chroma_format_idc == )
int residual_colour_transform_flag=u(,buf,StartBit);
int bit_depth_luma_minus8=Ue(buf,nLen,StartBit);
int bit_depth_chroma_minus8=Ue(buf,nLen,StartBit);
int qpprime_y_zero_transform_bypass_flag=u(,buf,StartBit);
int seq_scaling_matrix_present_flag=u(,buf,StartBit); int seq_scaling_list_present_flag[];
if( seq_scaling_matrix_present_flag )
{
for( int i = ; i < ; i++ ) {
seq_scaling_list_present_flag[i]=u(,buf,StartBit);
}
}
}
int log2_max_frame_num_minus4=Ue(buf,nLen,StartBit);
int pic_order_cnt_type=Ue(buf,nLen,StartBit);
if( pic_order_cnt_type == )
int log2_max_pic_order_cnt_lsb_minus4=Ue(buf,nLen,StartBit);
else if( pic_order_cnt_type == )
{
int delta_pic_order_always_zero_flag=u(,buf,StartBit);
int offset_for_non_ref_pic=Se(buf,nLen,StartBit);
int offset_for_top_to_bottom_field=Se(buf,nLen,StartBit);
int num_ref_frames_in_pic_order_cnt_cycle=Ue(buf,nLen,StartBit); int *offset_for_ref_frame=new int[num_ref_frames_in_pic_order_cnt_cycle];
for( int i = ; i < num_ref_frames_in_pic_order_cnt_cycle; i++ )
offset_for_ref_frame[i]=Se(buf,nLen,StartBit);
delete [] offset_for_ref_frame;
}
int num_ref_frames=Ue(buf,nLen,StartBit);
int gaps_in_frame_num_value_allowed_flag=u(,buf,StartBit);
int pic_width_in_mbs_minus1=Ue(buf,nLen,StartBit);
int pic_height_in_map_units_minus1=Ue(buf,nLen,StartBit); Width=(pic_width_in_mbs_minus1+)*;
Height=(pic_height_in_map_units_minus1+)*; return true;
}
else
return false;
} void CCommDlg::OnOK()
{
CString str;
//数据必须把H264的头0x000001去掉
BYTE bytes[]={0x67,0x64,0x08,0x1F,0xAC,0x34,0xC1,0x08,0x28,0x0F,0x64};
UINT startbit=;
int Width,Height;
if (h264_decode_seq_parameter_set(bytes,,Width,Height))
{
str.Format("%d-%d",Width,Height); AfxMessageBox(str);
}
}