nvidia打开摄像头推流c++代码

以下是一个使用NVIDIA的Video Codec SDK和FFmpeg库，通过摄像头推流的C++代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <chrono>
#include <thread>
#include <mutex>

#include "cuda.h"
#include "nvcodec/nvEncoder.h"
#include "nvcodec/nvUtils.h"

extern "C" {
#include "libavformat/avformat.h"
#include "libavutil/opt.h"
#include "libavutil/imgutils.h"
}

// FFmpeg variables
AVFormatContext *formatCtx = NULL;
AVOutputFormat *outputFmt = NULL;
AVStream *videoStream = NULL;
AVCodecContext *codecCtx = NULL;
AVPacket *pkt = NULL;
AVFrame *frame = NULL;
uint8_t *outBuffer = NULL;

// Encoder variables
nvEncoder *encoder = NULL;
uint8_t *nv12devPtr = NULL, *nv12sysPtr = NULL;
int nv12size = 0;

// Camera variables
const int camW = 640;
const int camH = 480;
const int camFPS = 30;
const int camDevice = 0;

std::mutex encoderMutex;

void initEncoder() {
    // Initialize the encoder
    encoder = new nvEncoder(NV_ENC_DEVICE_TYPE_CUDA, cudaDevice0);
    encoder->createEncoder(NV_ENC_H264, NV_ENC_PRESET_LOW_LATENCY_DEFAULT);

    // Set encoder params
    encoder->setEncodeCodecConfig(NV_ENC_CODEC_H264_GUID, NV_ENC_PRESET_LOW_LATENCY_DEFAULT_GUID);
    encoder->setEncodeWidth(camW);
    encoder->setEncodeHeight(camH);
    encoder->setFrameRate(camFPS);
    encoder->setBitrate(1000000);

    // Initialize buffers
    int nv12surfSize = 0;
    encoder->getMaximumOutputSize(&nv12size);
    cudaMalloc(&nv12devPtr, nv12size);
    cudaMallocHost(&nv12sysPtr, camW * camH * 3 / 2);
    cudaMemset(nv12devPtr, 0, nv12size);
}

void initFFmpeg() {
    // Initialize FFmpeg
    avformat_alloc_output_context2(&formatCtx, NULL, NULL, "rtmp://localhost/live/stream");
    outputFmt = formatCtx->oformat;

    // Add video stream
    videoStream = avformat_new_stream(formatCtx, NULL);
    codecCtx = avcodec_alloc_context3(NULL);
    codecCtx->codec_id = outputFmt->video_codec;
    codecCtx->width = camW;
    codecCtx->height = camH;
    codecCtx->time_base = (AVRational){1, camFPS};
    codecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
    codecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
    avcodec_parameters_from_context(videoStream->codecpar, codecCtx);

    // Open the output stream
    if (!(outputFmt->flags & AVFMT_NOFILE)) {
        avio_open(&formatCtx->pb, "rtmp://localhost/live/stream", AVIO_FLAG_WRITE);
    }

    // Write the header
    avformat_write_header(formatCtx, NULL);
}

void startCapture() {
    cv::VideoCapture cap(camDevice);
    cap.set(cv::CAP_PROP_FRAME_WIDTH, camW);
    cap.set(cv::CAP_PROP_FRAME_HEIGHT, camH);
    cap.set(cv::CAP_PROP_FPS, camFPS);
    cap.set(cv::CAP_PROP_CONVERT_RGB, false);

    int frameCount = 0;
    while (true) {