在之前的《SkeyeRTSPLive高效转码之SkeyeVideoDecoder高效解码》系列文章中我们已经将视频解码成了原始图像数据（YUV/RGB），然后根据不同的转码需求进行编码。如视频分辨率缩放，调整码率，多码率输出等；为了解决转码过程中编码高分辨率高质量或者高压缩率（如H265）耗时的问题，我们采用Nvidia硬件驱动编码器进行编码，以追求最高效率的转码和最低的推送延迟。
SkeyeVideoEncoder基Nvidia独立显卡的硬件编码库SkeyeNvEncoder
1. 接口声明如下：
class SkeyeNvEncoder
{
public:
//codec: 编码格式 0=h264, 1=h265/hevc
int InitNvEncoder(int width,int height,int fps=25, int bitrate=4096, int gop=50, int qp=28, int rcMode=/*NV_ENC_PARAMS_RC_2_PASS_QUALITY*/NV_ENC_PARAMS_RC_CONSTQP,
char* encoderPreset = "Default", int codec = 0,int nDeviceType=0, int nDeviceID=0 );
//H264获取SPS和PPS
int GetSPSAndPPS(unsigned char*sps,long&spslen,unsigned char*pps,long&ppslen);
//H265获取VPS,SPS和PPS
int GetH265VPSSPSAndPPS(unsigned char*vps, long&vpslen, unsigned char*sps, long&spslen, unsigned char*pps, long&ppslen);
// 编码InputFormat我们固定为YUV420PL（I420），可修改为NV12， YUY2 等等在Init（）时进行格式转换， [12/18/2016 dingshuai]
unsigned char* NvEncodeSync(unsigned char* pYUV420, int inLenth, int& outLenth, bool& bKeyFrame);
//关闭编码器，停止编码
int CloseNvEncoder();
};2. SkeyeNvEncoder编码库调用流程
- 第一步，初始化编码器及其参数
//初始化编码器参数
int InitNvEncoder(int width,int height,int fps, int bitrate, int gop,
int qp, int rcMode, char* encoderPreset , int codec, int nDeviceType, int nDeviceID)
{
//初始化设置参数 -- Start
memset(&m_encodeConfig, 0, sizeof(EncodeConfig));
m_encodeConfig.width = width;
m_encodeConfig.height = height;
m_nVArea = width*height;
m_nCheckyuvsize = m_nVArea*3/2;
//编码器识别的码率是bps, 但是我们输入的是kbps, so*1024
m_encodeConfig.bitrate = bitrate*1024;
//多通道编码优化图像质量只有在低延迟模式下工作（LOW_LATENCY）
m_encodeConfig.rcMode = rcMode;//NV_ENC_PARAMS_RC_2_PASS_QUALITY
m_encodeConfig.encoderPreset = encoderPreset; //NV_ENC_PARAMS_RC_2_PASS_QUALITY;
//默认指定低延时模式以及图像的压缩格式(HQ,HP,LOSSLESS ......)
m_encodeConfig.presetGUID = NV_ENC_PRESET_LOW_LATENCY_HQ_GUID;
// I帧间隔 [12/16/2016 dingshuai]
m_encodeConfig.gopLength = gop;//NVENC_INFINITE_GOPLENGTH;
//CUDA
m_encodeConfig.deviceType = nDeviceType;
m_encodeConfig.deviceID = nDeviceID;
m_encodeConfig.codec = codec;//NV_ENC_H264;
m_encodeConfig.fps = fps;
m_encodeConfig.qp = qp;
m_encodeConfig.i_quant_factor = DEFAULT_I_QFACTOR;
m_encodeConfig.b_quant_factor = DEFAULT_B_QFACTOR;
m_encodeConfig.i_quant_offset = DEFAULT_I_QOFFSET;
m_encodeConfig.b_quant_offset = DEFAULT_B_QOFFSET;
m_encodeConfig.pictureStruct = NV_ENC_PIC_STRUCT_FRAME;
//编码异步输出模式， 1-异步 0-同步
m_encodeConfig.enableAsyncMode = 0;
//默认输入给编码器的格式为NV12(所以需要格式转换：YUV420->NV12)
m_encodeConfig.inputFormat = NV_ENC_BUFFER_FORMAT_NV12;
//暂不知道这些参数什么用
m_encodeConfig.invalidateRefFramesEnableFlag = 0;
m_encodeConfig.endFrameIdx = INT_MAX;
//没有B帧，且目前编码器也不支持B帧，设了也没用
m_encodeConfig.numB = 0;
if (m_encodeConfig.numB > 0)
{
//PRINTERR("B-frames are not supported\n");
return -1;
}
// 其他参数，欢迎补充...... [12/18/2016 dingshuai]
//
//
//初始化设置参数 -- END
//初始化编码器 -- Start
NVENCSTATUS nvStatus = NV_ENC_SUCCESS;
switch (m_encodeConfig.deviceType)
{
#if defined(NV_WINDOWS)
case NV_ENC_DX9:
nvStatus = InitD3D9(m_encodeConfig.deviceID);
break;
case NV_ENC_DX10:
nvStatus = InitD3D10(m_encodeConfig.deviceID);
break;
case NV_ENC_DX11:
nvStatus = InitD3D11(m_encodeConfig.deviceID);
break;
#endif
// initialize Cuda
case NV_ENC_CUDA:
InitCuda(m_encodeConfig.deviceID,0);
break;
}
if (nvStatus != NV_ENC_SUCCESS)
return -1;
if (m_encodeConfig.deviceType != NV_ENC_CUDA)
nvStatus = m_pNvHWEncoder->Initialize(m_pDevice, NV_ENC_DEVICE_TYPE_DIRECTX);
else
nvStatus = m_pNvHWEncoder->Initialize(m_pDevice, NV_ENC_DEVICE_TYPE_CUDA);
if (nvStatus != NV_ENC_SUCCESS)
return 1;
//nvStatus = InitCuda(m_encodeConfig.deviceID, 0);
//nvStatus = m_pNvHWEncoder->Initialize((void*)m_cuContext, NV_ENC_DEVICE_TYPE_CUDA);
//if (nvStatus != NV_ENC_SUCCESS)
// return -2;
m_encodeConfig.presetGUID = m_pNvHWEncoder->GetPresetGUID(m_encodeConfig.encoderPreset, m_encodeConfig.codec);
nvStatus = m_pNvHWEncoder->CreateEncoder(&m_encodeConfig);
if (nvStatus != NV_ENC_SUCCESS)
{
Deinitialize();
return -3;
}
// 编码缓存帧数 [12/16/2016 dingshuai]
uint32_t uEncodeBufferCount = 1;
//分配编码缓冲区
nvStatus = AllocateIOBuffers(m_pNvHWEncoder->m_uMaxWidth, m_pNvHWEncoder->m_uMaxHeight, uEncodeBufferCount);
if (nvStatus != NV_ENC_SUCCESS)
return -4;
m_spslen = 0;
m_ppslen = 0;
memset(m_sps, 0x00, 100);
memset(m_pps, 0x00, 100);
m_bWorking = true;
return 1;
}其中，我们需要设置编码格式（0=H264，1=H265目前只支持这两种格式），视频分辨率，帧率，码率和I帧间隔（Gop）,编码质量以及硬件编码器相关参数，参数详解如下：
//rcMode: Rate Control Modes(编码码率/质量控制模式)，详见如下枚举：
// typedef enum _NV_ENC_PARAMS_RC_MODE
// {
// NV_ENC_PARAMS_RC_CONSTQP = 0x0, /**< Constant QP mode */
// NV_ENC_PARAMS_RC_VBR = 0x1, /**< Variable bitrate mode */
// NV_ENC_PARAMS_RC_CBR = 0x2, /**< Constant bitrate mode */
// NV_ENC_PARAMS_RC_VBR_MINQP = 0x4, /**< Variable bitrate mode with MinQP */
// NV_ENC_PARAMS_RC_2_PASS_QUALITY = 0x8, /**< Multi pass encoding optimized for image quality and works only with low latency mode */
// NV_ENC_PARAMS_RC_2_PASS_FRAMESIZE_CAP = 0x10, /**< Multi pass encoding optimized for maintaining frame size and works only with low latency mode */
// }
//encoderPreset: 编码预设
// 预设编码器编码图像的延时和清晰度
// if (encoderPreset && (stricmp(encoderPreset, "HQ") == 0))
// else if (encoderPreset && (stricmp(encoderPreset, "LowLatencyHP") == 0))
// else if (encoderPreset && (stricmp(encoderPreset, "HP") == 0))
// else if (encoderPreset && (stricmp(encoderPreset, "LowLatencyHQ") == 0))
// else if (encoderPreset && (stricmp(encoderPreset, "BD") == 0))
// else if (encoderPreset && (stricmp(encoderPreset, "LOSSLESS") == 0))
// else if (encoderPreset && (stricmp(encoderPreset, "LowLatencyDefault") == 0))
// else if (encoderPreset && (stricmp(encoderPreset, "LosslessDefault") == 0))
// 详见nvEncoderAPI.h /* Preset GUIDS supported by the NvEncodeAPI interface. */
- 第二步，获取编码信息参数
如果编码格式为H264，我们通过GetSPSAndPPS获取编码信息头SPS和PPS，如下代码段所示：
//获取SPS和PPS
int GetSPSAndPPS(unsigned char*sps,long&spslen,unsigned char*pps,long&ppslen)
{
if (!m_bWorking)
{
return -1;
}
if (m_spslen == 0 || m_ppslen == 0)
{
unsigned char* pEncData = NULL;
int nDataSize = 0;
bool bKeyFrame = false;
unsigned char* pTempBuffer = new unsigned char[m_nCheckyuvsize];
memset(pTempBuffer, 0x00, m_nCheckyuvsize);
pEncData = NvEncodeSync(pTempBuffer, m_nCheckyuvsize, nDataSize, bKeyFrame);
if (pEncData && nDataSize>0)
{
GetH264SPSandPPS((char*)pEncData, nDataSize, (char*)m_sps, (int*)&m_spslen, (char*)m_pps, (int*)&m_ppslen);
}
m_encPicCommand.bForceIDR = 1;
if (pTempBuffer)
{
delete[] pTempBuffer;
pTempBuffer = NULL;
}
}
if (m_spslen>0&&m_ppslen>0)
{
memcpy(sps, m_sps, m_spslen);
memcpy(pps, m_pps, m_ppslen);
spslen = m_spslen;
ppslen = m_ppslen;
}
return 1;
}
如果编码格式为H265，我们通过GetH265VPSSPSAndPPS获取编码信息头VPS,SPS和PPS，如下代码段所示：
int GetH265VPSSPSAndPPS(unsigned char*vps, long&vpslen, unsigned char*sps,
long&spslen, unsigned char*pps, long&ppslen)
{
if (!m_bWorking)
{
return -1;
}
if (m_spslen == 0 || m_ppslen == 0)
{
unsigned char* pEncData = NULL;
int nDataSize = 0;
bool bKeyFrame = false;
unsigned char* pTempBuffer = new unsigned char[m_nCheckyuvsize];
memset(pTempBuffer, 0x00, m_nCheckyuvsize);
pEncData = NvEncodeSync(pTempBuffer, m_nCheckyuvsize, nDataSize, bKeyFrame);
if (pEncData && nDataSize>0)
{
GetH265VPSandSPSandPPS((char*)pEncData, nDataSize, (char*)m_vps, (int*)&m_vpslen, (char*)m_sps, (int*)&m_spslen, (char*)m_pps, (int*)&m_ppslen);
}
m_encPicCommand.bForceIDR = 1;
if (pTempBuffer)
{
delete[] pTempBuffer;
pTempBuffer = NULL;
}
}
spslen = m_spslen;
ppslen = m_ppslen;
vpslen = m_vpslen;
if (m_spslen > 0)
memcpy(sps, m_sps, m_spslen);
if(m_ppslen>0)
memcpy(pps, m_pps, m_ppslen);
if(m_vpslen)
memcpy(vps, m_vps, m_vpslen);
return 1;
}第三步，调用编码函数进行视频帧编码
编码输入格式InputFormat我们固定为YUV420PL（I420），如源图像色彩格式为NV12， YUY2 等，需要在传入编码器时进行格式转换。unsigned char* NvEncodeSync(unsigned char* pYUV420, int inLenth, int& outLenth, bool& bKeyFrame) { if( !m_bWorking || inLenth !=m_nCheckyuvsize)//初始化尚未完成，或者传入的数据不满足YUV数据的长度，则返回错误 { outLenth = 0; return NULL; } NVENCSTATUS nvStatus = NV_ENC_SUCCESS; bool bError = false; EncodeBuffer* pEncodeBuffer = m_EncodeBufferQueue.GetAvailable(); EncodeFrameConfig stEncodeFrame; memset(&stEncodeFrame, 0, sizeof(stEncodeFrame)); stEncodeFrame.yuv[0] = pYUV420;//Y stEncodeFrame.yuv[1] = pYUV420+m_nVArea;//U stEncodeFrame.yuv[2] = pYUV420+m_nVArea+(m_nVArea>>2);//V int nHelfWidth = m_encodeConfig.width >> 1; stEncodeFrame.stride[0] = m_encodeConfig.width; stEncodeFrame.stride[1] = nHelfWidth; stEncodeFrame.stride[2] = nHelfWidth; stEncodeFrame.width = m_encodeConfig.width; stEncodeFrame.height = m_encodeConfig.height; if (m_encodeConfig.deviceType == 0)//CUDA { //CUDA Lock CCudaAutoLock cuLock((CUcontext)m_pDevice);//m_cuContext nvStatus = PreProcessInput(pEncodeBuffer, stEncodeFrame.yuv, stEncodeFrame.width, stEncodeFrame.height, m_pNvHWEncoder->m_uCurWidth, m_pNvHWEncoder->m_uCurHeight, m_pNvHWEncoder->m_uMaxWidth, m_pNvHWEncoder->m_uMaxHeight); if (nvStatus != NV_ENC_SUCCESS) { outLenth = 0; return NULL; } nvStatus = m_pNvHWEncoder->NvEncMapInputResource(pEncodeBuffer->stInputBfr.nvRegisteredResource, &pEncodeBuffer->stInputBfr.hInputSurface); if (nvStatus != NV_ENC_SUCCESS) { PRINTERR("Failed to Map input buffer %p\n", pEncodeBuffer->stInputBfr.hInputSurface); bError = true; outLenth = 0; return NULL; } } else//DirectX or any others { unsigned char *pInputSurface = NULL; uint32_t lockedPitch = 0; while (pInputSurface == NULL) { nvStatus = m_pNvHWEncoder->NvEncLockInputBuffer(pEncodeBuffer->stInputBfr.hInputSurface, (void**)&pInputSurface, &lockedPitch); if (nvStatus != NV_ENC_SUCCESS) return NULL; if (pInputSurface == NULL) { nvStatus = m_pNvHWEncoder->NvEncUnlockInputBuffer(pEncodeBuffer->stInputBfr.hInputSurface); if (nvStatus != NV_ENC_SUCCESS) return NULL; Sleep(1); } } if (pEncodeBuffer->stInputBfr.bufferFmt == NV_ENC_BUFFER_FORMAT_NV12_PL) { unsigned char *pInputSurfaceCh = pInputSurface + (pEncodeBuffer->stInputBfr.dwHeight*lockedPitch); CmnConvertYUVtoNV12(stEncodeFrame.yuv[0], stEncodeFrame.yuv[1], stEncodeFrame.yuv[2], pInputSurface, pInputSurfaceCh, stEncodeFrame.width, stEncodeFrame.height, stEncodeFrame.width, lockedPitch); } } nvStatus = m_pNvHWEncoder->NvEncEncodeFrame(pEncodeBuffer, &m_encPicCommand, m_encodeConfig.width, m_encodeConfig.height, NV_ENC_PIC_STRUCT_FRAME, m_qpDeltaMapArray, m_qpDeltaMapArraySize); if (nvStatus != NV_ENC_SUCCESS) { bError = true; outLenth= 0; return NULL; } pEncodeBuffer = m_EncodeBufferQueue.GetAvailable(); if (!pEncodeBuffer) { pEncodeBuffer = m_EncodeBufferQueue.GetPending(); // 获取编码的h264/h265数据 [12/15/2016 dingshuai] nvStatus = m_pNvHWEncoder->ProcessOutput(pEncodeBuffer, m_pOutputBuffer, m_nOutputBufLen); if(nvStatus != NV_ENC_SUCCESS) { bError = true; outLenth= 0; } if (m_encodeConfig.deviceType == 0)//CUDA { // UnMap the input buffer after frame done if (pEncodeBuffer->stInputBfr.hInputSurface) { nvStatus = m_pNvHWEncoder->NvEncUnmapInputResource(pEncodeBuffer->stInputBfr.hInputSurface); pEncodeBuffer->stInputBfr.hInputSurface = NULL; } //pEncodeBuffer = m_EncodeBufferQueue.GetAvailable(); } else { nvStatus = m_pNvHWEncoder->NvEncUnlockInputBuffer(pEncodeBuffer->stInputBfr.hInputSurface); if (nvStatus != NV_ENC_SUCCESS) return NULL; } } else { outLenth= 0; return NULL; } if (m_encPicCommand.bForceIDR) { m_encPicCommand.bForceIDR = 0; } outLenth = m_nOutputBufLen; return m_pOutputBuffer; }- 第四步，关闭编码器，释放编码器申请的内存和显卡资源
int CloseNvEncoder()
{
m_bWorking = false;
NVENCSTATUS nvStatus = NV_ENC_SUCCESS;
ReleaseIOBuffers();
m_pNvHWEncoder->NvEncDestroyEncoder();
if (m_cuContext)
{
__cu(cuCtxDestroy(m_cuContext));
}
return nvStatus;
}
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