音视频技术应用(12) 测试sleep和wait的精确度达到准确控制帧率的目的

 测试几种sleep的方式：

#include <iostream>
#include <ctime>
#include <thread>
#include <windows.h>

using namespace std;

void MSleep(unsigned int ms)
{
    auto beg = clock();
    for (int i = 0; i < ms; i++)
    {
        this_thread::sleep_for(1ms);
        if ((clock() - beg) / (CLOCKS_PER_SEC / 1000) >= ms)
            break;
    }
}

int main()
{

    // ================================ 1. 测试C++11的 sleep 控制帧率 ================================
    //测试c++11的sleep
    //测试 sleep 10毫秒 100fps
    auto beg = clock(); //开始时间 ，cpu跳数
    int fps = 0;        //帧率
    for (;;)
    {
        fps++;
        auto tmp = clock();
        this_thread::sleep_for(10ms);
        //cout << clock() - tmp << " " << flush;
        //1秒钟开始统计 CLOCKS_PER_SEC CPU每秒跳数
        if ((clock() - beg) / (CLOCKS_PER_SEC / 1000) > 1000)  //间隔毫秒数
        {
            cout << "sleep for fps:" << fps << endl;
            break;
        }
    }

    // =========================== 2. 测试 Windows wait 事件超时控制 帧率 =======================================
    auto handle = CreateEvent(NULL, FALSE, FALSE, NULL);
    fps = 0;
    beg = clock();
    for (;;)
    {
        fps++;
        WaitForSingleObject(handle, 10);// 等待超时
        if ((clock() - beg) / (CLOCKS_PER_SEC / 1000) > 1000)  //间隔毫秒数
        {
            cout << "wait fps:" << fps << endl;
            break;
        }
    }

    // =========================== 3. 测试使用MSleep()函数 控制 帧率 =======================================
    fps = 0;
    beg = clock();
    for (;;)
    {
        fps++;
        MSleep(10);
        if ((clock() - beg) / (CLOCKS_PER_SEC / 1000) > 1000)  //间隔毫秒数
        {
            cout << "MSleep fps:" << fps << endl;
            break;
        }
    }

    getchar();
    return 0;
}

运行结果：

sleep for fps:93
wait fps:96
MSleep fps:97