fffmpeg推流摄像头c++代码

FFmpeg是一款非常强大的音视频处理库，可以用来进行音视频的编解码、格式转换、推流等操作。下面是一个简单的C++代码示例，用于将摄像头采集到的视频数据进行推流：

#include <iostream>
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
}
using namespace std;

int main()
{
    AVFormatContext *fmt_ctx = NULL;
    AVCodecContext *codec_ctx = NULL;
    AVCodec *codec = NULL;
    AVStream *stream = NULL;
    AVPacket pkt;
    int ret;

    // 打开摄像头
    cv::VideoCapture cap(0);
    if (!cap.isOpened())
    {
        cerr << "Could not open camera" << endl;
        return -1;
    }

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

    // 创建输出上下文
    ret = avformat_alloc_output_context2(&fmt_ctx, NULL, "flv", "rtmp://localhost/live");
    if (ret < 0)
    {
        cerr << "Could not allocate output context" << endl;
        return -1;
    }

    // 查找编码器
    codec = avcodec_find_encoder(AV_CODEC_ID_H264);
    if (!codec)
    {
        cerr << "Could not find encoder" << endl;
        return -1;
    }

    // 创建新的流
    stream = avformat_new_stream(fmt_ctx, codec);
    if (!stream)
    {
        cerr << "Could not create new stream" << endl;
        return -1;
    }

    // 配置编码器上下文
    codec_ctx = avcodec_alloc_context3(codec);
    if (!codec_ctx)
    {
        cerr << "Could not allocate codec context" << endl;
        return -1;
    }
    codec_ctx->width = cap.get(CV_CAP_PROP_FRAME_WIDTH);
    codec_ctx->height = cap.get(CV_CAP_PROP_FRAME_HEIGHT);
    codec_ctx->pix_fmt = AV_PIX_FMT_YUV420P;
    codec_ctx->time_base.num = 1;
    codec_ctx->time_base.den = 25;

    // 打开编码器
    ret = avcodec_open2(codec_ctx, codec, NULL);
    if (ret < 0)
    {
        cerr << "Could not open codec" << endl;
        return -1;
    }

    // 将编码器上下文复制到流中
    ret = avcodec_parameters_from_context(stream->codecpar, codec_ctx);
    if (ret < 0)
    {
        cerr << "Could not copy codec parameters" << endl;
        return -1;
    }
    stream->time_base = codec_ctx->time_base;

    // 打开输出流
    ret = avio_open(&fmt_ctx->pb, fmt_ctx->url, AVIO_FLAG_WRITE);
    if (ret < 0)
    {
        cerr << "Could not open output stream" << endl;
        return -1;
    }

    // 写入文件头部
    ret = avformat_write_header(fmt_ctx, NULL);
    if (ret < 0)
    {
        cerr << "Error writing header" << endl;
        return -1;
    }

    // 创建图像缩放上下文
    struct SwsContext *sws_ctx = sws_getContext(codec_ctx->width, codec_ctx->height,
                                                AV_PIX_FMT_BGR24, codec_ctx->width, codec_ctx->height,
                                                AV_PIX_FMT_YUV420P, SWS_BILINEAR, NULL, NULL, NULL);
    if (!sws_ctx)
    {
        cerr << "Could not initialize the conversion context" << endl;
        return -1;
    }

    // 读取摄像头数据并推流
    while (true)
    {
        cv::Mat frame;
        cap.read(frame);
        if (frame.empty()) break;

        // 将图像转换为YUV420P格式
        AVFrame *yuv_frame = av_frame_alloc();
        yuv_frame->width = codec_ctx->width;
        yuv_frame->height = codec_ctx->height;
        yuv_frame->format = AV_PIX_FMT_YUV420P;
        av_image_alloc(yuv_frame->data, yuv_frame->linesize, codec_ctx->width, codec_ctx->height, AV_PIX_FMT_YUV420P, 32);
        sws_scale(sws_ctx, (const uint8_t * const *)frame.data, frame.step, 0, codec_ctx->height,
                  yuv_frame->data, yuv_frame->linesize);

        // 编码图像数据并写入输出流
        av_init_packet(&pkt);
        pkt.data = NULL; // 设置数据指针为NULL，防止出现奇怪的问题
        pkt.size = 0;
        ret = avcodec_send_frame(codec_ctx, yuv_frame);
        if (ret < 0)
        {
            cerr << "Error sending frame to codec" << endl;
            return -1;
        }
        while (ret >= 0)
        {
            ret = avcodec_receive_packet(codec_ctx, &pkt);
            if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) break;
            if (ret < 0)
            {
                cerr << "Error encoding packet" << endl;
                return -1;
            }
            pkt.stream_index = stream->index;
            av_packet_rescale_ts(&pkt, codec_ctx->time_base, stream->time_base);
            ret = av_interleaved_write_frame(fmt_ctx, &pkt);
            if (ret < 0)
            {
                cerr << "Error writing packet" << endl;
                return -1;
            }
            av_packet_unref(&pkt);
        }
        av_frame_free(&yuv_frame);
    }

    // 写入文件尾部
    ret = av_write_trailer(fmt_ctx);
    if (ret < 0)
    {
        cerr << "Error writing trailer" << endl;
        return -1;
    }

    // 清理资源
    avformat_close_input(&fmt_ctx);
    avformat_free_context(fmt_ctx);
    avcodec_free_context(&codec_ctx);

    return 0;
}

请注意，这只是一个简单的示例代码，实际情况可能会更加复杂。另外，需要安装OpenCV和FFmpeg库才能编译运行该代码。如果你还没有安装这些库，请先进行安装。