写一个使用ffmpeg 5.1.2版本播放rtsp流，vs2019可以编译通过的播放器

好的，我可以为您提供一个简单的使用FFmpeg 5.1.2版本播放rtsp流的播放器示例，但是需要您自行编译FFmpeg库。

首先，您需要从FFmpeg官网（https://ffmpeg.org/download.html）下载FFmpeg 5.1.2版本的源代码，并按照官方指南进行编译。

接下来，您可以使用以下示例代码进行播放：

#include <iostream>
#include <string>
#include <chrono>
#include <thread>

extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswresample/swresample.h>
#include <libswscale/swscale.h>
#include <SDL2/SDL.h>
}

int main(int argc, char* argv[])
{
    // 初始化FFmpeg库
    av_register_all();
    avformat_network_init();

    // 创建AVFormatContext
    AVFormatContext* pFormatCtx = avformat_alloc_context();
    if (!pFormatCtx) {
        std::cerr << "Failed to allocate AVFormatContext." << std::endl;
        return EXIT_FAILURE;
    }

    // 打开rtsp流
    std::string rtspUrl = "rtsp://example.com/stream";
    if (avformat_open_input(&pFormatCtx, rtspUrl.c_str(), nullptr, nullptr) != 0) {
        std::cerr << "Failed to open rtsp stream." << std::endl;
        return EXIT_FAILURE;
    }

    // 获取流信息
    if (avformat_find_stream_info(pFormatCtx, nullptr) < 0) {
        std::cerr << "Failed to get stream information." << std::endl;
        return EXIT_FAILURE;
    }

    // 查找视频流
    int videoStreamIndex = -1;
    for (unsigned int i = 0; i < pFormatCtx->nb_streams; i++) {
        if (pFormatCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
            videoStreamIndex = i;
            break;
        }
    }
    if (videoStreamIndex == -1) {
        std::cerr << "Failed to find video stream." << std::endl;
        return EXIT_FAILURE;
    }

    // 获取视频解码器
    AVCodec* pCodec = avcodec_find_decoder(pFormatCtx->streams[videoStreamIndex]->codecpar->codec_id);
    if (!pCodec) {
        std::cerr << "Failed to find video decoder." << std::endl;
        return EXIT_FAILURE;
    }

    // 创建AVCodecContext
    AVCodecContext* pCodecCtx = avcodec_alloc_context3(pCodec);
    if (!pCodecCtx) {
        std::cerr << "Failed to allocate AVCodecContext." << std::endl;
        return EXIT_FAILURE;
    }

    // 设置AVCodecContext参数
    if (avcodec_parameters_to_context(pCodecCtx, pFormatCtx->streams[videoStreamIndex]->codecpar) < 0) {
        std::cerr << "Failed to set AVCodecContext parameters." << std::endl;
        return EXIT_FAILURE;
    }

    // 打开视频解码器
    if (avcodec_open2(pCodecCtx, pCodec, nullptr) < 0) {
        std::cerr << "Failed to open video decoder." << std::endl;
        return EXIT_FAILURE;
    }

    // 创建AVFrame和AVPacket
    AVFrame* pFrame = av_frame_alloc();
    if (!pFrame) {
        std::cerr << "Failed to allocate AVFrame." << std::endl;
        return EXIT_FAILURE;
    }
    AVPacket* pPacket = av_packet_alloc();
    if (!pPacket) {
        std::cerr << "Failed to allocate AVPacket." << std::endl;
        return EXIT_FAILURE;
    }

    // 创建SwsContext
    SwsContext* pSwsCtx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
        pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_RGB24, SWS_BILINEAR, nullptr, nullptr, nullptr);
    if (!pSwsCtx) {
        std::cerr << "Failed to create SwsContext." << std::endl;
        return EXIT_FAILURE;
    }

    // 初始化SDL库
    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        std::cerr << "Failed to initialize SDL library." << std::endl;
        return EXIT_FAILURE;
    }

    // 创建SDL窗口
    SDL_Window* pWindow = SDL_CreateWindow("RTSP Player", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
        pCodecCtx->width, pCodecCtx->height, SDL_WINDOW_SHOWN);
    if (!pWindow) {
        std::cerr << "Failed to create SDL window." << std::endl;
        return EXIT_FAILURE;
    }

    // 创建SDL渲染器
    SDL_Renderer* pRenderer = SDL_CreateRenderer(pWindow, -1, SDL_RENDERER_ACCELERATED);
    if (!pRenderer) {
        std::cerr << "Failed to create SDL renderer." << std::endl;
        return EXIT_FAILURE;
    }

    // 创建SDL纹理
    SDL_Texture* pTexture = SDL_CreateTexture(pRenderer, SDL_PIXELFORMAT_RGB24,
        SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);
    if (!pTexture) {
        std::cerr << "Failed to create SDL texture." << std::endl;
        return EXIT_FAILURE;
    }

    // 读取视频帧
    while (av_read_frame(pFormatCtx, pPacket) >= 0) {
        if (pPacket->stream_index == videoStreamIndex) {
            // 解码视频帧
            if (avcodec_send_packet(pCodecCtx, pPacket) == 0) {
                while (avcodec_receive_frame(pCodecCtx, pFrame) == 0) {
                    // 转换帧格式
                    AVFrame* pFrameRGB = av_frame_alloc();
                    if (!pFrameRGB) {
                        std::cerr << "Failed to allocate AVFrame." << std::endl;
                        return EXIT_FAILURE;
                    }
                    av_image_alloc(pFrameRGB->data, pFrameRGB->linesize, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_RGB24, 1);
                    sws_scale(pSwsCtx, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize);

                    // 显示帧
                    SDL_UpdateTexture(pTexture, nullptr, pFrameRGB->data[0], pFrameRGB->linesize[0]);
                    SDL_RenderClear(pRenderer);
                    SDL_RenderCopy(pRenderer, pTexture, nullptr, nullptr);
                    SDL_RenderPresent(pRenderer);

                    // 释放帧内存
                    av_frame_free(&pFrameRGB);
                }
            }
        }
        av_packet_unref(pPacket);

        // 暂停一段时间以控制帧率
        std::this_thread::sleep_for(std::chrono::milliseconds(33));
    }

    // 释放资源
    av_packet_free(&pPacket);
    av_frame_free(&pFrame);
    avcodec_close(pCodecCtx);
    avformat_close_input(&pFormatCtx);
    sws_freeContext(pSwsCtx);
    SDL_DestroyTexture(pTexture);
    SDL_DestroyRenderer(pRenderer);
    SDL_DestroyWindow(pWindow);
    SDL_Quit();

    return EXIT_SUCCESS;
}

请注意，此示例仅适用于Windows平台，并使用SDL库进行视频显示。如果您在其他平台上运行此示例，您需要相应地更改代码以适应不同的平台和库。