XDemux.cpp

#include "XDemux.h"
#include "AVPacketRAII.h"
#include <iostream>
using namespace std;
extern "C" {
#include "libavformat/avformat.h"
}
#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;
}

bool XDemux::Open(const char* url)
{
	Close();
	//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);

	std::unique_lock<mutex> lck(mux);
	int re = avformat_open_input(
		&ic,
		url,
		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)
	{
		lck.unlock();
		char buf[1024] = { 0 };
		av_strerror(re, buf, sizeof(buf) - 1);
		cout << "open " << url << " failed! :" << buf << endl;
		return false;
	}
	cout << "open " << url << " success! " << endl;

	//获取流信息 
	re = avformat_find_stream_info(ic, 0);

	//总时长 毫秒
	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, url, 0);


	//获取视频流
	videoStream = av_find_best_stream(ic, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
	AVStream* as = ic->streams[videoStream];
	width = as->codecpar->width;
	height = as->codecpar->height;

	cout << "=======================================================" << endl;
	cout << videoStream << "视频信息" << endl;
	cout << "codec_id = " << as->codecpar->codec_id << endl;
	cout << "format = " << as->codecpar->format << 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;

	cout << "=======================================================" << endl;
	cout << audioStream << "音频信息" << endl;
	//获取音频流
	audioStream = av_find_best_stream(ic, AVMEDIA_TYPE_AUDIO, -1, -1, NULL, 0);
	as = ic->streams[audioStream];
	sampleRate = as->codecpar->sample_rate;
	channels = as->codecpar->channels;

	cout << "codec_id = " << as->codecpar->codec_id << endl;
	cout << "format = " << as->codecpar->format << endl;
	cout << "sample_rate = " << as->codecpar->sample_rate << endl;
	//AVSampleFormat;
	cout << "channels = " << as->codecpar->channels << endl;
	//一帧数据？？ 单通道样本数 
	cout << "frame_size = " << as->codecpar->frame_size << endl;
	//1024 * 2 * 2 = 4096  fps = sample_rate/frame_size
	return true;
}
//清空读取缓存
void XDemux::Clear()
{
	std::unique_lock<mutex> lck(mux);
	if (!ic)
	{
		return;
	}
	//清理读取缓冲
	avformat_flush(ic);
}
void XDemux::Close()
{
	std::unique_lock<mutex> lck(mux);
	if (!ic)
	{
		return;
	}
	avformat_close_input(&ic);
	//媒体总时长（毫秒）
	totalMs = 0;
}

//seek 位置 pos 0.0 ~1.0
bool XDemux::Seek(double pos)
{
	std::unique_lock<mutex> lck(mux);
	if (!ic)
	{
		return false;
	}
	//清理读取缓冲
	avformat_flush(ic);

	long long seekPos = 0;
	seekPos = ic->streams[videoStream]->duration * pos;
	int re = av_seek_frame(ic, videoStream, seekPos, AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_FRAME);
	if (re < 0) return false;
	return true;
}
//获取视频参数  返回的空间需要清理  avcodec_parameters_free
AVCodecParameters* XDemux::CopyVPara()
{
	std::unique_lock<mutex> lck(mux);
	if (!ic) {
		return nullptr;
	}
	AVCodecParameters* pa = avcodec_parameters_alloc();
	avcodec_parameters_copy(pa, ic->streams[videoStream]->codecpar);
	return pa;
}

//获取音频参数  返回的空间需要清理 avcodec_parameters_free
AVCodecParameters* XDemux::CopyAPara()
{
	std::unique_lock<mutex> lck(mux);
	if (!ic) {
		return nullptr;
	}
	AVCodecParameters* pa = avcodec_parameters_alloc();
	avcodec_parameters_copy(pa, ic->streams[audioStream]->codecpar);
	return pa;
}

shared_ptr<AVPacketRAII> XDemux::ReadVideo() {
	shared_ptr<AVPacketRAII> pkt;
	// 防止阻塞
	for (int i = 0; i < 20; i++) {
		pkt = Read();
		if (!pkt)break;
		if (pkt->get_avpacket()->stream_index == videoStream) break;
	}
	return pkt;
}

bool XDemux::IsAudio(shared_ptr<AVPacketRAII> pkt)
{
	if (!pkt) return false;
	if (pkt->get_avpacket()->stream_index == videoStream)
		return false;
	return true;

}
//空间需要调用者释放 ，释放AVPacket对象空间，和数据空间 av_packet_free
shared_ptr<AVPacketRAII> XDemux::Read()
{
	std::unique_lock<mutex> lck(mux);
	if (!ic) //容错
	{
		return 0;
	}
	shared_ptr<AVPacketRAII> pkt = make_shared<AVPacketRAII>();
	//读取一帧，并分配空间
	int re = av_read_frame(ic, pkt->get_avpacket());
	if (re != 0)
	{
		return 0;
	}
	lck.unlock();
	//pts转换为毫秒
	pkt->get_avpacket()->pts = pkt->get_avpacket()->pts * (1000 * (r2d(ic->streams[pkt->get_avpacket()->stream_index]->time_base)));
	pkt->get_avpacket()->dts = pkt->get_avpacket()->dts * (1000 * (r2d(ic->streams[pkt->get_avpacket()->stream_index]->time_base)));
	// cout << pkt->get_avpacket()->pts << " " << flush;
	return pkt;

}
XDemux::XDemux()
{
	static bool isFirst = true;
	static std::mutex dmux;
	std::unique_lock<mutex> lck(dmux);
	if (isFirst)
	{
		//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();
		isFirst = false;
	}
}


XDemux::~XDemux()
{
}