ffmpeg拉流rtmp并保存flv

秒速五厘米 2023-10-16 12:56 38阅读 0赞

##### 代码实现如下： #####

#include <thread>
    #include <iostream>
    extern "C"
    {
    #include <libavcodec/avcodec.h>
    #include <libavformat/avformat.h>
    }
    
    int main()
    {  
        AVOutputFormat *ofmt = NULL;
        AVFormatContext *ifmt_ctx = NULL;
        AVFormatContext *ofmt_ctx = NULL;
        AVPacket *pkt = NULL;
        const char *in_filename = "rtmp://vlive2018.people.com.cn/2010/cctv132019/live_2000";
        const char *out_filename = "out.flv";
        int ret = -1;
        bool stop = false;
        // 初始化网络
        avformat_network_init(); 
    
        // 初始化输入格式上下文  
        if ((ifmt_ctx = avformat_alloc_context()) == NULL) {
            std:: cout << "avformat_alloc_context failed." << std::endl;
            exit(1);
        }
    
        // 打开输入格式上下文
        if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
            std:: cout << "Could not open input file." << std::endl;
            exit(1);
        }
        
        // 获取输入信息
        if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
            std:: cout << "Failed to retrieve input stream information" << std::endl;
            return -1;
        }
        
        // 申请pkt
        if (!(pkt = av_packet_alloc())) {
            std:: cout << "Could not allocate packet"<< std::endl;
            return -1;
        }
        
        // 打开输出格式上下文
        if ((ret = avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename)) < 0 || !ofmt_ctx) {
            std:: cout << "Could not create output context" << std::endl; 
            return -1;
        }
        ofmt = ofmt_ctx->oformat;    
    
        // 关联输入输出
        for (int i = 0; i < ifmt_ctx->nb_streams; i++) {
            AVStream *in_stream = ifmt_ctx->streams[i];
            AVStream *out_stream = avformat_new_stream(ofmt_ctx, NULL);
            if (!out_stream) {
                std:: cout << "Failed allocating output stream" << std::endl;
            } else
            {
                if ((ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar)) < 0) {
                    std:: cout << "Failed to copy codec context to out_stream codecpar context" << std::endl;           
                }
            }
        }
     
        av_dump_format(ifmt_ctx, 0, in_filename, 0);
        av_dump_format(ofmt_ctx, 0, out_filename, 1);
        
        if (!(ofmt->flags & AVFMT_NOFILE)) {
            if ((ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE)) < 0) {
                std:: cout << "Could not open output URL" << std::string(out_filename) << std::endl;
                return -1;
            }
        }
        // 写入头
        if ((ret = avformat_write_header(ofmt_ctx, NULL)) < 0) {
            std:: cout << "Error occurred when opening output URL" << std::endl;
            return -1;
        }
        
        std::thread th([&]{
            while (av_read_frame(ifmt_ctx, pkt) >= 0 && !stop) {           
                // 写入数据
                if (av_interleaved_write_frame(ofmt_ctx, pkt) < 0) {
                    std:: cout << "Error muxing packet" << std::endl;
                    break;
                }
                av_packet_unref(pkt);
            }
            // 写入尾数据
            av_write_trailer(ofmt_ctx);    
        });
        
        std::cout << "input char to stop" << std::endl;
        while(getchar() != 'q');
    
        stop = true;
        if (th.joinable())
        {
    	    th.join();
        }
        
        // 释放
        avformat_close_input(&ifmt_ctx);
        av_packet_free(&pkt);
        /* close output */
        if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE)) {
            avio_close(ofmt_ctx->pb);
        } 
        avformat_free_context(ofmt_ctx);
    
        return 0;
    }