Windows下FFmpeg之保存网络流到本地文件

视频教程来自王纲，在此记录下，方便以后使用

• 头文件 pch.h

#ifndef PCH_H
#define PCH_H

extern "C"
{
#include "include\libavutil\opt.h"
#include "include\libavutil\channel_layout.h"
#include "include\libavutil\common.h"
#include "include\libavutil\imgutils.h"
#include "include\libavutil\mathematics.h"
#include "include\libavutil\samplefmt.h"
#include "include\libavutil\time.h"
#include "include\libavutil\fifo.h"
#include "include\libavcodec\avcodec.h"
#include "include\libavformat\avformat.h"
#include "include\libavformat\avio.h"
#include "include\libavfilter\avfilter.h"
#include "include\libavfilter\buffersink.h"
#include "include\libavfilter\buffersrc.h"
#include "include\libswscale\swscale.h"
#include "include\libswresample\swresample.h"
}
#endif

• 核心代码

#include "stdafx.h"

#include 
#include
#include "pch.h"
#include 

using namespace std;

AVFormatContext *inputContext = nullptr;
AVFormatContext *outputContext;

int OpenInput(string inputUrl){
    inputContext = avformat_alloc_context();
    int ret = avformat_open_input(&inputContext, inputUrl.c_str(), nullptr, nullptr);
    if (ret < 0){
        av_log(NULL, AV_LOG_ERROR, "Input file open input failed\n");
        return ret;
    }

    ret = avformat_find_stream_info(inputContext, nullptr);
    if (ret < 0){
        av_log(NULL, AV_LOG_ERROR, "Find input stream inform failed\n");
    }
    else{
        av_log(NULL, AV_LOG_FATAL, "Open input file %s success\n", inputUrl.c_str());
    }
    return ret;
}

shared_ptr ReadPacketFromSource()
{
    shared_ptr packet(static_cast(av_malloc(sizeof(AVPacket))), [&](AVPacket *p){av_packet_free(&p); });

    av_init_packet(packet.get());
    int ret = av_read_frame(inputContext, packet.get());
    if (ret >= 0){
        return packet;

    }
    else{
        return nullptr;
    }
}

void av_packet_rescale_ts(AVPacket *pkt, AVRational src_tb, AVRational dst_tb){
    if (pkt->pts != AV_NOPTS_VALUE)
        pkt->pts = av_rescale_q(pkt->pts, src_tb, dst_tb);
    if (pkt->dts != AV_NOPTS_VALUE)
        pkt->dts = av_rescale_q(pkt->dts, src_tb, dst_tb);

    if (pkt->duration > 0)
        pkt->duration = av_rescale_q(pkt->duration, src_tb, dst_tb);
}

int WritePacket(shared_ptr packet)
{
    auto inputStream = inputContext->streams[packet->stream_index];
    auto outputStream = outputContext->streams[packet->stream_index];
    av_packet_rescale_ts(packet.get(), inputStream->time_base, outputStream->time_base);
    return av_interleaved_write_frame(outputContext, packet.get());
}

int OpenOutput(string outUrl){
    int ret = avformat_alloc_output_context2(&outputContext, nullptr, "mpegts", outUrl.c_str());
    if (ret < 0){
        av_log(NULL, AV_LOG_ERROR, "Open output context failed\n");
        goto Error;
    }
    ret = avio_open2(&outputContext->pb, outUrl.c_str(), AVIO_FLAG_READ_WRITE, nullptr, nullptr);
    if (ret < 0){
        av_log(NULL, AV_LOG_ERROR, "Open avio failed\n");
        goto Error;
    }

    for (int i = 0; i < inputContext->nb_streams; i++){
        AVStream *stream = avformat_new_stream(outputContext, inputContext->streams[i]->codec->codec);
        ret = avcodec_copy_context(stream->codec, inputContext->streams[i]->codec);
        if (ret < 0){
            av_log(NULL, AV_LOG_ERROR, "copy codec context failed\n");
            goto Error;
        }
    }

    ret = avformat_write_header(outputContext, nullptr);

    if (ret < 0){
        av_log(NULL, AV_LOG_ERROR, "format write header failed\n");
        goto Error;
    }

    av_log(NULL, AV_LOG_FATAL, "open output file success %s\n", outUrl.c_str());
    return ret;

Error:
    if (outputContext){
        for (int i = 0; i < outputContext->nb_streams; i++){
            avcodec_close(outputContext->streams[i]->codec);
        }
        avformat_close_input(&outputContext);
    }
    return ret;
}


void Init(){
    av_register_all();
    avfilter_register_all();
    avformat_network_init();
    av_log_set_level(AV_LOG_ERROR);
}

int _tmain(int argc, _TCHAR* argv[])
{

    Init();
    int ret = OpenInput("rtmp://live.hkstv.hk.lxdns.com/live/hks");
    //int ret = OpenInput("E:\\input.mp4");
    if (ret >= 0){
        ret = OpenOutput("E:\\test2.ts");
    }
    if (ret < 0){
        goto Error;
    }

    while (true){
        auto packet = ReadPacketFromSource();
        if (packet){
            ret = WritePacket(packet);
            if (ret >= 0){
                cout << "WritePacket Success" << endl;
            }
            else{
                cout << "WritePacket failed" << endl;
            }
        }
    }

Error:
    while (true){
        this_thread::sleep_for(chrono::seconds(100));
    }

    return 0;
}