#include <iostream>
#include <thread>
extern "C"{
#include "libavformat/avformat.h"
#include "libavcodec/avcodec.h"
}
using namespace std;
#pragma comment(lib,"avformat.lib")
#pragma comment(lib,"avutil.lib")
#pragma comment(lib,"avcodec.lib")
static double r2d(AVRational r)
{
	return r.den == 0 ? 0:(double)r.num / (double)r.den;
}
void XSleep(int ms)
{
	//c++ 11
	chrono::milliseconds du(ms);
	this_thread::sleep_for(du);
}
int main(int argc, char *argv[])
{
	cout << "Test Demux FFmpeg.club" << endl;
	const char *path = "v1080.mp4";
	//初始化封装库
	av_register_all();

	//初始化网络库 （可以打开rtsp rtmp http 协议的流媒体视频）
	avformat_network_init();

	//注册解码器
	avcodec_register_all();

	//参数设置
	AVDictionary *opts = NULL;
	
	//设置rtsp流已tcp协议打开
	av_dict_set(&opts, "rtsp_transport", "tcp", 0);

	//网络延时时间
	av_dict_set(&opts, "max_delay", "500", 0);


	//解封装上下文
	AVFormatContext *ic = NULL;
	int re = avformat_open_input(
		&ic,
		path,
		0,  // 0表示自动选择解封器
		&opts //参数设置，比如rtsp的延时时间
	);
	if (re != 0)
	{
		char buf[1024] = { 0 };
		av_strerror(re, buf, sizeof(buf) - 1);
		cout << "open " << path << " failed! :" << buf << endl;
		getchar();
		return -1;
	}
	cout << "open " << path << " success! " << endl;

	//获取流信息 
	re = avformat_find_stream_info(ic, 0);
	
	//总时长 毫秒
	int totalMs = ic->duration / (AV_TIME_BASE / 1000);
	cout << "totalMs = " << totalMs << endl;

	//打印视频流详细信息
	av_dump_format(ic,0,path,0);

	//音视频索引，读取时区分音视频
	int videoStream = 0;
	int audioStream = 1;

	//获取音视频流信息 （遍历，函数获取）
	for (int i = 0; i < ic->nb_streams; i++)
	{
		AVStream *as = ic->streams[i];
		cout << "codec_id = " << as->codecpar->codec_id << endl;
		cout << "format = " << as->codecpar->format << endl;

		//音频 AVMEDIA_TYPE_AUDIO
		if (as->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)
		{
			audioStream = i;
			cout <<i<< "音频信息" << endl;
			cout << "sample_rate = " << as->codecpar->sample_rate << endl;
			//AVSampleFormat;
			cout << "channels = " << as->codecpar->channels << endl;
			//一帧数据   frame_size 单通道样本数 
			cout << "frame_size = " << as->codecpar->frame_size << endl;
			//1024 * 2 * 2 = 4096  fps = sample_rate/frame_size
			
		}
		//视频 AVMEDIA_TYPE_VIDEO
		else if (as->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
		{
			videoStream = i;
			cout << i << "视频信息" << endl;
			cout << "width=" << as->codecpar->width << endl;
			cout << "height=" << as->codecpar->height << endl;
			//帧率 fps 分数转换
			cout<<"video fps = " <<r2d(as->avg_frame_rate)<<endl;
		}
	}

	//使用函数获取视频流
	videoStream = av_find_best_stream(ic, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);


	///视频解码器打开
	///通过id找到视频解码器
	AVCodec *vcodec = avcodec_find_decoder(ic->streams[videoStream]->codecpar->codec_id);
	if (!vcodec)
	{
		cout << "can't find the codec id " << ic->streams[videoStream]->codecpar->codec_id;
		getchar();
		return -1;
	}
	cout << "find the AVCodec " << ic->streams[videoStream]->codecpar->codec_id << endl;
	//注册解码器上下文
	AVCodecContext *vc = avcodec_alloc_context3(vcodec);

	///配置解码器上下文参数  codecpar包含许多类型的数据
	avcodec_parameters_to_context(vc, ic->streams[videoStream]->codecpar);
	//指定八线程解码
	vc->thread_count = 8;

	///打开解码器上下文
	re = avcodec_open2(vc, 0, 0);
	if (re != 0)
	{
		char buf[1024] = { 0 };
		av_strerror(re, buf, sizeof(buf) - 1);
		cout << "avcodec_open2  failed! :" << buf << endl;
		getchar();
		return -1;
	}
	cout << "video avcodec_open2 success!" << endl;


	//
	///音频解码器打开
	AVCodec *acodec = avcodec_find_decoder(ic->streams[audioStream]->codecpar->codec_id);
	if (!acodec)
	{
		cout << "can't find the codec id " << ic->streams[audioStream]->codecpar->codec_id;
		getchar();
		return -1;
	}
	cout << "find the AVCodec " << ic->streams[audioStream]->codecpar->codec_id << endl;
	///创建解码器上下文呢
	AVCodecContext *ac = avcodec_alloc_context3(acodec);

	///配置解码器上下文参数
	avcodec_parameters_to_context(ac, ic->streams[audioStream]->codecpar);
	//八线程解码
	ac->thread_count = 8;

	///打开解码器上下文
	re = avcodec_open2(ac, 0, 0);
	if (re != 0)
	{
		char buf[1024] = { 0 };
		av_strerror(re, buf, sizeof(buf) - 1);
		cout << "avcodec_open2  failed! :" << buf << endl;
		getchar();
		return -1;
	}
	cout << "audio avcodec_open2 success!" << endl;

	///ic->streams[videoStream]
	//malloc AVPacket和frame并初始化
	AVPacket *pkt = av_packet_alloc();
	AVFrame *frame = av_frame_alloc(); 
	for (;;)
	{
	     //Return the next frame of a stream.
	     将帧的信息填入pkt中
		int re = av_read_frame(ic, pkt);
		if (re != 0)
		{
			//循环播放
			cout << "==============================end==============================" << endl;
			int ms = 3000; //三秒位置 根据时间基数（分数）转换
			long long pos = (double)ms/ (double)1000*r2d(ic->streams[pkt->stream_index]->time_base);
			// 在时间戳处查找关键帧。
			av_seek_frame(ic, videoStream, pos, AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_FRAME);
			continue;
		}
		cout << "pkt->size = "<< pkt->size << endl;
		//显示的时间
		cout << "pkt->pts = " << pkt->pts << endl;
		
		//转换为毫秒，方便做同步
		cout << "pkt->pts ms = " << pkt->pts * (r2d(ic->streams[pkt->stream_index]->time_base) * 1000) << endl;



		//解码时间
		cout << "pkt->dts = " << pkt->dts << endl;

		AVCodecContext *cc = 0;
		if (pkt->stream_index == videoStream)
		{
			cout << "图像" << endl;
			cc = vc;
		}
		if (pkt->stream_index == audioStream)
		{
			cout << "音频" << endl;
			cc = ac;
		}

		///解码视频
		//发送packet到解码线程  send传NULL后调用多次receive取出所有缓冲帧
		re = avcodec_send_packet(cc, pkt);
		//释放，引用计数-1 为0释放空间
		av_packet_unref(pkt);

		if (re != 0)
		{
		//打印错误
			char buf[1024] = { 0 };
			av_strerror(re, buf, sizeof(buf) - 1);
			cout << "avcodec_send_packet  failed! :" << buf << endl;
			continue;
		}

		for(;;)
		{
			//从线程中获取解码接口,一次send可能对应多次receive
			//从解码器获取帧数据
			re = avcodec_receive_frame(cc,frame);
			if (re != 0) break;
			cout << "recv frame " << frame->format << " " << frame->linesize[0] << endl;
		}



		//XSleep(500);
	}
	av_frame_free(&frame);
	av_packet_free(&pkt);



	if (ic)
	{
		//释放封装上下文，并且把ic置0
		avformat_close_input(&ic);
	}

	getchar();
	return 0;
}```