c# - 录制桌面时如何停止ffmpeg将文件保存到硬盘？

Question

我正在尝试使用 ffmpeg 录制桌面并将视频文件保存到硬盘。

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Testings
{
    internal class FFmpeg_Capture
    {
        Process process;

        public FFmpeg_Capture()
        {
            process = new Process();
        }

        public void Start(string FileName, int Framerate)
        {
            process.StartInfo.FileName = @"D:\Captured Videos\ffmpeg.exe"; // Change the directory where ffmpeg.exe is.  
            process.EnableRaisingEvents = false;
            process.StartInfo.WorkingDirectory = @"D:\Captured Videos"; // The output directory  
            process.StartInfo.Arguments = @"-f gdigrab -framerate " + Framerate +
                " -i desktop -preset ultrafast - pix_fmt yuv420p " + FileName;
            process.Start();
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.CreateNoWindow = false;
            Stop();
        }

        public void Stop()
        {
            process.Close();
        }
    }
}

并在 form1 中使用它:

private void btnRecord_Click(object sender, EventArgs e)
        {
            recordToggle = !recordToggle;

            if (recordToggle)
            {
                btnRecord.Text = "Stop";
                record.Start("Testing", 60);
            }
            else
            {
                btnRecord.Text = "Record";
                record.Stop();
            }
        }

但文件测试从未保存到硬盘上。我的猜测是

process.Close();

不像 ctrl+ c 和 ctrl + c 是停止 ffmpeg 并保存文件的原因。
这是有效的，但如何删除 ffmpeg 的黑色窗口？

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.IO.Pipes;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Testings
{
    internal class FFmpeg_Capture
    {
        Process process;

        public FFmpeg_Capture()
        {
            process = new Process();
        }

        public void Start(string FileName, int Framerate)
        {
            process.StartInfo.FileName = @"D:\Captured Videos\ffmpeg.exe"; // Change the directory where ffmpeg.exe is.  
            process.EnableRaisingEvents = false;
            process.StartInfo.WorkingDirectory = @"D:\Captured Videos\"; // The output directory  
            process.StartInfo.Arguments = @"-y -f gdigrab -framerate " + Framerate +
                " -i desktop -preset ultrafast -pix_fmt yuv420p " + FileName;
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.CreateNoWindow = false;
            process.StartInfo.RedirectStandardInput = true; //Redirect stdin
            process.Start();
        }

        public void Stop()
        {
            byte[] qKey = Encoding.GetEncoding("gbk").GetBytes("q"); //Get encoding of 'q' key
            process.StandardInput.BaseStream.Write(qKey, 0, 1); //Write 'q' key to stdin of FFmpeg sub-processs
            process.StandardInput.BaseStream.Flush(); //Flush stdin (just in case).
            process.Close();
        }
    }
}

Answer 1

当我们开始录制时，会出现以下消息:

Press [q] to stop, [?] for help.

将 'q' 写入 stdin模拟按压 q键，然后停止录制。

使用 RedirectStandardInput = true 启动 FFmpeg 子进程:

 process.StartInfo.RedirectStandardInput = true;
 process.Start();

写q stdin 的 key FFmpeg 子流程的管道:

 byte[] qKey = Encoding.GetEncoding("gbk").GetBytes("q");
 process.StandardInput.BaseStream.Write(qKey, 0, 1);

完整的代码示例:

using System.Diagnostics;
using System.Text;

namespace Testings
{
    internal class FFmpeg_Capture
    {
        Process process;

        public FFmpeg_Capture()
        {
            process = new Process();
        }

        public void Start(string FileName, int Framerate)
        {
            process.StartInfo.FileName = @"C:\FFmpeg\bin\ffmpeg.exe"; // Change the directory where ffmpeg.exe is.  
            process.EnableRaisingEvents = false;
            process.StartInfo.WorkingDirectory = @"D:\"; // The output directory  
            process.StartInfo.Arguments = @"-y -f gdigrab -framerate " + Framerate +
                " -i desktop -preset ultrafast -pix_fmt yuv420p " + FileName;            
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.CreateNoWindow = false;
            process.StartInfo.RedirectStandardInput = true; //Redirect stdin
            process.Start();
            System.Threading.Thread.Sleep(3000);  //Wait 3 seconds (for testing).
            Stop();
        }

        public void Stop()
        {
            byte[] qKey = Encoding.GetEncoding("gbk").GetBytes("q"); //Get encoding of 'q' key
            process.StandardInput.BaseStream.Write(qKey, 0, 1); //Write 'q' key to stdin of FFmpeg sub-processs
            process.StandardInput.BaseStream.Flush(); //Flush stdin (just in case).
            process.Close();
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            FFmpeg_Capture cap = new FFmpeg_Capture();
            cap.Start("vid.mp4", 5);
        }
    }
}