LINUX C++ ffmpeg 摄像头 推流 代码示例

这里提供一个简单的示例代码，使用FFmpeg推送摄像头采集到的视频流：

#include <iostream>
#include <thread>
#include <chrono>
#include <opencv2/opencv.hpp>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>

using namespace std;
using namespace cv;

int main(int argc, char* argv[])
{
    // 打开摄像头
    VideoCapture cap(0);
    if (!cap.isOpened())
    {
        cerr << "Failed to open camera!" << endl;
        return -1;
    }

    // 初始化FFmpeg
    av_register_all();
    avformat_network_init();

    // 创建输出上下文
    AVFormatContext* outctx = nullptr;
    if (avformat_alloc_output_context2(&outctx, nullptr, "flv", "rtmp://localhost/live/test") < 0)
    {
        cerr << "Failed to create output context!" << endl;
        return -1;
    }

    // 添加视频流
    AVCodecID codec_id = AV_CODEC_ID_H264;
    AVCodec* codec = avcodec_find_encoder(codec_id);
    if (!codec)
    {
        cerr << "Failed to find encoder!" << endl;
        return -1;
    }
    AVStream* outstream = avformat_new_stream(outctx, codec);
    if (!outstream)
    {
        cerr << "Failed to create stream!" << endl;
        return -1;
    }
    outstream->codecpar->codec_id = codec_id;
    outstream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
    outstream->codecpar->width = cap.get(CV_CAP_PROP_FRAME_WIDTH);
    outstream->codecpar->height = cap.get(CV_CAP_PROP_FRAME_HEIGHT);
    outstream->codecpar->format = AV_PIX_FMT_YUV420P;

    // 打开编码器
    if (avcodec_open2(outstream->codec, codec, nullptr) < 0)
    {
        cerr << "Failed to open encoder!" << endl;
        return -1;
    }

    // 打开输出流
    if (!(outctx->oformat->flags & AVFMT_NOFILE))
    {
        if (avio_open(&outctx->pb, outctx->url, AVIO_FLAG_WRITE) < 0)
        {
            cerr << "Failed to open output stream!" << endl;
            return -1;
        }
    }

    // 写文件头
    if (avformat_write_header(outctx, nullptr) < 0)
    {
        cerr << "Failed to write header!" << endl;
        return -1;
    }

    // 初始化图像转换器
    SwsContext* swsctx = sws_getContext(cap.get(CV_CAP_PROP_FRAME_WIDTH), cap.get(CV_CAP_PROP_FRAME_HEIGHT), AV_PIX_FMT_BGR24,
        outstream->codecpar->width, outstream->codecpar->height, outstream->codecpar->format, SWS_BICUBIC, nullptr, nullptr, nullptr);
    if (!swsctx)
    {
        cerr << "Failed to create image converter!" << endl;
        return -1;
    }

    // 循环读取视频帧并推送
    Mat frame;
    AVFrame* avframe = av_frame_alloc();
    avframe->format = outstream->codecpar->format;
    avframe->width = outstream->codecpar->width;
    avframe->height = outstream->codecpar->height;
    av_frame_get_buffer(avframe, 32);
    while (true)
    {
        cap >> frame;
        if (frame.empty())
            break;

        // 转换图像格式
        uint8_t* data[AV_NUM_DATA_POINTERS] = { 0 };
        data[0] = frame.data;
        int linesize[AV_NUM_DATA_POINTERS] = { 0 };
        linesize[0] = frame.step;
        sws_scale(swsctx, data, linesize, 0, frame.rows, avframe->data, avframe->linesize);

        // 编码并发送视频帧
        AVPacket pkt = { 0 };
        av_init_packet(&pkt);
        int ret = avcodec_send_frame(outstream->codec, avframe);
        if (ret < 0)
        {
            cerr << "Failed to send frame!" << endl;
            break;
        }
        while (ret >= 0)
        {
            ret = avcodec_receive_packet(outstream->codec, &pkt);
            if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                break;
            else if (ret < 0)
            {
                cerr << "Error while encoding frame!" << endl;
                break;
            }

            // 发送数据包
            av_packet_rescale_ts(&pkt, outstream->codec->time_base, outstream->time_base);
            pkt.stream_index = outstream->index;
            ret = av_interleaved_write_frame(outctx, &pkt);
            if (ret < 0)
                cerr << "Failed to write packet!" << endl;
            av_packet_unref(&pkt);
        }

        // 等待一段时间
        this_thread::sleep_for(chrono::milliseconds(30));
    }

    // 写文件尾
    av_write_trailer(outctx);

    // 释放资源
    avcodec_close(outstream->codec);
    avcodec_free_context(&outstream->codec);
    avformat_free_context(outctx);
    av_frame_free(&avframe);
    sws_freeContext(swsctx);

    return 0;
}

请注意修改代码中的推流地址和编码器参数，以适应你的需求。