NVENC編碼流程
- 加載NVENCODE API
- 打開編碼會話
- 初始化編碼器
- 注冊輸入資源
- 映射注冊的輸入資源
- 創(chuàng)建輸出比特流緩沖
- 編碼一幀（同步方式）
- 獲取輸出（同步方式）
加載API
將NVENC lib中的接口導(dǎo)出邦蜜，供后續(xù)編碼流程使用帜乞。
NV_ENCODE_API_FUNCTION_LIST m_funList = { NV_ENCODE_API_FUNCTION_LIST_VER };
NVENC_API_CALL(NvEncodeAPICreateInstance(&m_funList));
打開編碼會話
編碼會話需要傳入D3D設(shè)備，在此之前需要創(chuàng)建好D3D設(shè)備。接口輸出的void* m_encoder;將會用于后續(xù)編碼接口的第一個參數(shù)中缚俏。
NV_ENC_OPEN_ENCODE_SESSION_EX_PARAMS encodeSessionExParams = { 0 };
encodeSessionExParams.version = NV_ENC_OPEN_ENCODE_SESSION_EX_PARAMS_VER;
encodeSessionExParams.device = (void*)m_device;
encodeSessionExParams.deviceType = NV_ENC_DEVICE_TYPE_DIRECTX;
encodeSessionExParams.apiVersion = NVENCAPI_VERSION;
void* m_encoder;
NVENC_API_CALL(m_funList.nvEncOpenEncodeSessionEx(&encodeSessionExParams, &m_encoder));
初始化編碼器
可以使用nvEncInitializeEncoder傳入NV_ENC_INITIALIZE_PARAMS類型的實例，對編碼器進行初始化菱父。其中encodeGUID挣饥、encodeWidth、encodeHeight三項是必填選項地回，encodeGUID表示使用H264編碼(NV_ENC_CODEC_H264_GUID)還是H265(NV_ENC_CODEC_HEVC_GUID)編碼扁远。另外，還可以在此設(shè)置使用同步編碼還是異步編碼模式刻像。
nvEncGetEncodePresetConfig可以獲取預(yù)置參數(shù)NV_ENC_PRESET_CONFIG畅买。可以設(shè)置碼率控制模式细睡、平均碼率等數(shù)據(jù)谷羞。
NV_ENC_PRESET_CONFIG presetConfig = { NV_ENC_PRESET_CONFIG_VER, { NV_ENC_CONFIG_VER } };
m_funList.nvEncGetEncodePresetConfig(m_encoder, NV_ENC_CODEC_H264_GUID, NV_ENC_PRESET_P3_GUID, &presetConfig);
NV_ENC_CONFIG config = { NV_ENC_CONFIG_VER };
memcpy(&config, &presetConfig.presetCfg, sizeof(config));
config.rcParams.rateControlMode = NV_ENC_PARAMS_RC_CBR;
config.rcParams.averageBitRate = 25000;
config.gopLength = 10;
NV_ENC_INITIALIZE_PARAMS encoder_init_params = { NV_ENC_INITIALIZE_PARAMS_VER };
encoder_init_params.encodeConfig = &config;
encoder_init_params.encodeGUID = NV_ENC_CODEC_H264_GUID;
encoder_init_params.presetGUID = NV_ENC_PRESET_P3_GUID;
encoder_init_params.tuningInfo = NV_ENC_TUNING_INFO_ULTRA_LOW_LATENCY;
encoder_init_params.encodeWidth = m_encodeWidth;
encoder_init_params.encodeHeight = m_encodeHeight;
encoder_init_params.darWidth = m_encodeWidth;
encoder_init_params.darHeight = m_encodeHeight;
encoder_init_params.frameRateNum = m_frameRate; // 幀率
encoder_init_params.frameRateDen = 1;
encoder_init_params.enablePTD = 1;
encoder_init_params.maxEncodeWidth = m_encodeWidth;
encoder_init_params.maxEncodeHeight = m_encodeHeight;
encoder_init_params.enableEncodeAsync = 0; // 同步模式
NVENC_API_CALL(m_funList.nvEncInitializeEncoder(m_encoder, &encoder_init_params));
注冊輸入資源
將輸入的紋理指針注冊成輸入資源，即m_registerResource.resourceToRegister = m_inputTexture;
NV_ENC_REGISTER_RESOURCE m_registerResource;
m_registerResource.version = NV_ENC_REGISTER_RESOURCE_VER;
m_registerResource.resourceType = NV_ENC_INPUT_RESOURCE_TYPE_DIRECTX;
m_registerResource.resourceToRegister = m_inputTexture;
m_registerResource.width = m_encodeWidth;
m_registerResource.height = m_encodeHeight;
m_registerResource.pitch = 0;
m_registerResource.bufferFormat = NV_ENC_BUFFER_FORMAT_NV12;
m_registerResource.bufferUsage = NV_ENC_INPUT_IMAGE;
m_registerResource.pInputFencePoint = NULL;
m_registerResource.pOutputFencePoint = NULL;
NVENC_API_CALL(m_funList.nvEncRegisterResource(m_encoder, &m_registerResource));
映射注冊的輸入資源
將注冊的輸入資源映射到編碼器溜徙。m_inputMapResource.registeredResource = m_registerResource.registeredResource;
NV_ENC_MAP_INPUT_RESOURCE m_inputMapResource;
m_inputMapResource.version = NV_ENC_MAP_INPUT_RESOURCE_VER;
m_inputMapResource.registeredResource = m_registerResource.registeredResource;
NVENC_API_CALL(m_funList.nvEncMapInputResource(m_encoder, &m_inputMapResource));
創(chuàng)建輸出比特流緩沖
創(chuàng)建接收編碼出的比特流緩沖洒宝。
NV_ENC_CREATE_BITSTREAM_BUFFER m_outputBuffer;
m_outputBuffer.version = NV_ENC_CREATE_BITSTREAM_BUFFER_VER;
NVENC_API_CALL(m_funList.nvEncCreateBitstreamBuffer(m_encoder, &m_outputBuffer));
編碼一幀
在編碼前需要更新輸入紋理數(shù)據(jù)，即前面已經(jīng)注冊的紋理指針m_inputTexture萌京，更新后雁歌，填充NV_ENC_PIC_PARAMS結(jié)構(gòu)，將NV_ENC_PIC_PARAMS.inputBuffer賦值為前面映射的資源知残，即m_inputMapResource.mappedResource靠瞎，再將NV_ENC_PIC_PARAMS.outputBitstream賦值為前面創(chuàng)建的輸出比特流緩沖，即m_outputBuffer.bitstreamBuffer，然后調(diào)用nvEncEncodePicture對數(shù)據(jù)進行編碼乏盐。
NV_ENC_PIC_PARAMS picParams = { 0 };
picParams.version = NV_ENC_PIC_PARAMS_VER;
picParams.pictureStruct = NV_ENC_PIC_STRUCT_FRAME;
picParams.inputBuffer = m_inputMapResource.mappedResource;
picParams.bufferFmt = NV_ENC_BUFFER_FORMAT_NV12;
picParams.inputWidth = m_encodeWidth;
picParams.inputHeight = m_encodeHeight;
picParams.outputBitstream = m_outputBuffer.bitstreamBuffer;
picParams.inputTimeStamp = 0;
NVENC_API_CALL(m_funList.nvEncEncodePicture(m_encoder, &picParams));
獲取輸出
使用nvEncLockBitstream將數(shù)據(jù)從編碼器中取出佳窑，即GPU到CPU。
NV_ENC_LOCK_BITSTREAM lockBitstreamData = { NV_ENC_LOCK_BITSTREAM_VER };
lockBitstreamData.outputBitstream = m_outputBuffer.bitstreamBuffer;
lockBitstreamData.doNotWait = 0;
NVENC_API_CALL(m_funList.nvEncLockBitstream(m_encoder, &lockBitstreamData));
unsigned char* outData = NULL;
int dataSize = lockBitstreamData.bitstreamSizeInBytes;
outData = new unsigned char[dataSize];
memcpy(outData, lockBitstreamData.bitstreamBufferPtr, dataSize);
NVENC_API_CALL(m_funList.nvEncUnlockBitstream(m_encoder, lockBitstreamData.outputBitstream));
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