我尝试了以下方法,以每秒25帧率记录视频,持续10秒,但当我得到输出视频时,它是2秒,帧播放速度比视频流快。
代码如下:
using System;
using System.Drawing;
using System.Windows.Forms;
using AForge.Video;
using AForge.Video.DirectShow;
using System.Threading;
using AForge.Video.FFMPEG;
namespace AforgeTutorial
{
public partial class Form1 : Form
{
private FilterInfoCollection ListOfCams;
private VideoCaptureDevice SelectedCam; //From where we will take image
System.Timers.Timer tim;
Thread t;
bool isNewFrame = false;
VideoFileWriter writer;
public Form1()
{
InitializeComponent();
tim = new System.Timers.Timer(10000);
tim.Elapsed += new System.Timers.ElapsedEventHandler(tim_Elapsed);
t = new Thread(saveVideo);
}
void tim_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
if (isRecord)
{
writer.Close();
isRecord = false;
}
}
private void Form1_Load(object sender, EventArgs e)
{
ListOfCams = new FilterInfoCollection(FilterCategory.VideoInputDevice);
if (ListOfCams.Count == 0)
return;
comboBox1.Items.Clear();
foreach (FilterInfo Cam in ListOfCams)
{
comboBox1.Items.Add(Cam.Name);
}
}
private void StopCamera()
{
SelectedCam.SignalToStop();
SelectedCam.Stop();
}
bool isRecord = false;
private void Start_Click(object sender, EventArgs e)
{
if (comboBox1.Text == string.Empty)
return;
SelectedCam = new VideoCaptureDevice(ListOfCams[comboBox1.SelectedIndex].MonikerString);
SelectedCam.NewFrame += new NewFrameEventHandler(SelectedCam_NewFrame);
SelectedCam.Start();
}
Bitmap image;
void SelectedCam_NewFrame(object sender, NewFrameEventArgs eventArgs)
{
image = (Bitmap)eventArgs.Frame.Clone();
isNewFrame = true;
pictureBox1.Image = (Bitmap)eventArgs.Frame.Clone();
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
StopCamera();
}
private void Stop_Click(object sender, EventArgs e)
{
StopCamera();
}
private void btnRecord_Click(object sender, EventArgs e)
{
tim.Start();
if (!isRecord)
{
writer = new VideoFileWriter();
writer.Open(@"C:/code-bude_test_video.mp4", 640, 480, 25, VideoCodec.MPEG4,10000);
}
isRecord = !isRecord;
if (isRecord)
t.Start();
}
void saveVideo()
{
while (isRecord)
{
if (isNewFrame)
{
writer.WriteVideoFrame(image);
isNewFrame = false;
}
}
}
}
}
您的代码中存在多线程问题。你不能像这样写入共享变量,并期望它同步。
你有三个线程:用户界面,流和保存。(SelectedCam_NewFrame在AForge流线程中运行)。列出至少在两个线程(isRecord, isNewFrame等)中访问的所有变量,并添加适当的同步。
你可以查看这个非常好的c#线程参考。
请注意,即使有同步,如果您的写入线程在几个图像到达时很忙,您可能会错过帧。您可能想要做的是将相机生成的帧收集到队列中,并在写入线程中使用该队列。查看生产者/消费者模式