如何正确使用OpenH264使用代码示例进行编码

我有一个图像，想用OpenH264对它进行编码。

到目前为止，这是我从他们的wiki中得到的代码：

#include <fstream>
#include <iterator>
#include <iostream>
#include <codec_api.h> //standard api for openh264
//additional libaries used by sample code
#include <codec_app_def.h>
#include <codec_def.h>
#include <codec_ver.h>
#include <assert.h>
#include <vector>
#include <cstring>
int main()
{
//parameter values
int width = 1920;
int height = 1080;
int framerate = 60;
int bitrate = 5000000;
int total_num = 500; //what does this value do?
//end parameter values
//Read in the File from bmp
std::vector<char> buf; //to store the image information
std::basic_ifstream<char> file("/home/megamol/Git/h264_sample/build/test.bmp", std::ios::binary); //opens bitstream to source
buf = std::vector<char>((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>()); // reads in data to the vector
std::cout << "sizeof buf: " << buf.size() << std::endl;
//Step 1: set up Encoder
ISVCEncoder* encoder_;    //declaration of encoder pointer
int rv = WelsCreateSVCEncoder (&encoder_);
//Step 2: initialize with basic parameter
SEncParamBase param;
memset(&param, 0, sizeof (SEncParamBase));
param.iUsageType = EUsageType::SCREEN_CONTENT_REAL_TIME;
param.fMaxFrameRate = framerate;
param.iPicWidth = width;
param.iPicHeight = height;
param.iTargetBitrate = bitrate; //default value of example
encoder_->Initialize(&param);
//Step 3: set video format
int videoFormat = videoFormatI420;
encoder_->SetOption (ENCODER_OPTION_DATAFORMAT, &videoFormat);
//Step 4: encocode and store output bitstream
int frameSize = width * height * 3 / 2;
buf.resize(frameSize);  
SFrameBSInfo info;
std::vector<char> compressedData;
memset (&info, 0, sizeof (SFrameBSInfo));
SSourcePicture pic;
memset (&pic, 0, sizeof (SSourcePicture));
pic.iPicWidth = width;
pic.iPicHeight = height;
pic.iColorFormat = videoFormatI420;
pic.iStride[0] = pic.iPicWidth;
pic.iStride[1] = pic.iStride[2] = pic.iPicWidth >> 1;
pic.pData[0] = reinterpret_cast<unsigned char*>(&buf[0]);
pic.pData[1] = pic.pData[0] + width * height;
pic.pData[2] = pic.pData[1] + (width * height >> 2);
//encodes the frame
rv = encoder_->EncodeFrame (&pic, &info); // encodes the Frame
//encoding done encoded Frame should be stored in &info
//begin decoding block
ISVCDecoder *pSvcDecoder;
unsigned char *pBuf= &info;
return 0;
}

我不完全确定这是否是OpenH264的正确用法，但我也不确定如何正确测试它。

现在，代码示例的文档有点不完整。

例如，什么是BufferedData buf;？我知道这应该是输入，但那是什么类型的？比如我如何将test.bmp加载为BufferedData？我认为我做得还不对。

另一件我很困惑的事情是，如何在编码后访问输出？在这个例子中，它只是说//output bitstream，而没有说在任何地方保存这个输出。我认为输出是info，就像在codec_api.h头文件中所说的那样：

/**
* @brief Encode one frame
* @param kpSrcPic the pointer to the source luminance plane
*        chrominance data:
*        CbData = kpSrc  +  m_iMaxPicWidth * m_iMaxPicHeight;
*        CrData = CbData + (m_iMaxPicWidth * m_iMaxPicHeight)/4;
*        the application calling this interface needs to ensure the data validation between the location
* @param pBsInfo output bit stream
* @return  0 - success; otherwise -failed;
*/
virtual int EXTAPI EncodeFrame (const SSourcePicture* kpSrcPic, SFrameBSInfo* pBsInfo) = 0;

但显然，它只保存有关输出的信息。我只是对这一切感到困惑。