c++用ffmpeg实现rtsp服务器

要实现一个基于RTSP协议的服务器，可以使用FFmpeg库。下面是一个简单的C++代码示例，可以用来实现一个基本的RTSP服务器：

#include <iostream>
#include <string>
#include <sstream>
#include <cstdlib>

#include <unistd.h>
#include <signal.h>

extern "C" {
#include <libavformat/avformat.h>
}

using namespace std;

static bool is_running = true;

static void signal_handler(int signum)
{
    is_running = false;
}

int main(int argc, char** argv)
{
    if (argc < 3) {
        cout << "Usage: " << argv[0] << " <input_file> <rtsp_url>" << endl;
        return -1;
    }

    signal(SIGINT, signal_handler);
    signal(SIGTERM, signal_handler);
    signal(SIGPIPE, SIG_IGN);

    av_register_all();
    avformat_network_init();

    AVFormatContext* input_format_context = nullptr;
    AVDictionary* options = nullptr;

    int ret = avformat_open_input(&input_format_context, argv[1], nullptr, &options);
    if (ret < 0) {
        cout << "Failed to open input file: " << argv[1] << endl;
        return -1;
    }

    ret = avformat_find_stream_info(input_format_context, nullptr);
    if (ret < 0) {
        cout << "Failed to find stream information" << endl;
        return -1;
    }

    AVOutputFormat* output_format = av_guess_format("rtsp", nullptr, nullptr);
    if (!output_format) {
        cout << "Failed to guess output format" << endl;
        return -1;
    }

    AVFormatContext* output_format_context = nullptr;
    ret = avformat_alloc_output_context2(&output_format_context, output_format, "rtsp", argv[2]);
    if (ret < 0) {
        cout << "Failed to allocate output context" << endl;
        return -1;
    }

    for (int i = 0; i < input_format_context->nb_streams; i++) {
        AVStream* stream = avformat_new_stream(output_format_context, nullptr);
        if (!stream) {
            cout << "Failed to create new stream" << endl;
            return -1;
        }

        ret = avcodec_parameters_copy(stream->codecpar, input_format_context->streams[i]->codecpar);
        if (ret < 0) {
            cout << "Failed to copy codec parameters" << endl;
            return -1;
        }

        stream->codecpar->codec_tag = 0;
    }

    if (!(output_format_context->oformat->flags & AVFMT_NOFILE)) {
        ret = avio_open(&output_format_context->pb, argv[2], AVIO_FLAG_WRITE);
        if (ret < 0) {
            cout << "Failed to open output URL: " << argv[2] << endl;
            return -1;
        }
    }

    ret = avformat_write_header(output_format_context, nullptr);
    if (ret < 0) {
        cout << "Failed to write header" << endl;
        return -1;
    }

    AVPacket packet;
    av_init_packet(&packet);

    while (is_running) {
        ret = av_read_frame(input_format_context, &packet);
        if (ret < 0) {
            break;
        }

        packet.stream_index = 0;

        ret = av_write_frame(output_format_context, &packet);
        if (ret < 0) {
            cout << "Failed to write frame" << endl;
            return -1;
        }

        av_packet_unref(&packet);
    }

    av_write_trailer(output_format_context);

    if (output_format_context && !(output_format_context->oformat->flags & AVFMT_NOFILE)) {
        avio_closep(&output_format_context->pb);
    }

    avformat_close_input(&input_format_context);

    return 0;
}

这个简单的服务器通过使用FFmpeg库来读取指定的视频文件，并将其转换为RTSP流。要启动服务器，请执行以下命令：

./rtsp_server input_file rtsp://localhost:8554/stream

其中`input_file`是要转换的视频文件的路径，`rtsp://localhost:8554/stream`是要创建的RTSP URL。