2019/10/27, .Net c#代码片段
网上很多版本都是需要等待4s的做法，这里不需要等待固定4s
添加引用，此命名空间用于对系统类型进行判断，选取不同的命令对象：
using System.Runtime.InteropServices;
/// <summary>
/// 借助ffmpeg生成缩略图
/// </summary>
/// <param name="originalFilePath">源文件</param>
public void GenerateThumbnail(string originalFilePath)
{
try
{
//判断系统类型
//如果是windows，直接使用ffmpeg.exe
//如果是linux，则使用安装的ffmpeg（需要提前安装）
/*
Linux工具调用：ffmpeg -i 333.jpg -q:v 31 -frames:v 1 -y image.jpg
windows: ffmpeg.exe -i 333.jpg -q:v 31 -frames:v 1 -y image.jpg
-i 333.jpg 是输入文件
-q:v 31 是质量，值区间是2-31
-frames:v 1 是提取帧必要参数
-y 是遇到同名文件则覆盖
image.jpg 输出文件名
还可以加 -s 160*100 表示输出宽高比为160*100
*/
string outputFilePath = "image.jpg";//输出文件
string cmdPath = string.Empty;//ffmpeg工具对象
string cmdParams = $" -i {originalFilePath} -q:v 31 -frames:v 1 -y {outputFilePath} ";//命令参数
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
cmdPath = "ffmpeg.exe";//根据实际的ffmpeg.exe文件路径来
}
else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
{
cmdPath = "ffmpeg";//安装ffmpeg工具
}
else
{
throw new Exception("当前操作系统不支持！");
}
using (System.Diagnostics.Process ffmpegProcess = new System.Diagnostics.Process())
{
StreamReader errorReader; // StringWriter to hold output from ffmpeg
// execute the process without opening a shell
ffmpegProcess.StartInfo.UseShellExecute = false;
//ffmpegProcess.StartInfo.ErrorDialog = false;
ffmpegProcess.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
// redirect StandardError so we can parse it
ffmpegProcess.StartInfo.RedirectStandardError = true;
// set the file name of our process, including the full path
// (as well as quotes, as if you were calling it from the command-line)
ffmpegProcess.StartInfo.FileName = cmdPath;
// set the command-line arguments of our process, including full paths of any files
// (as well as quotes, as if you were passing these arguments on the command-line)
ffmpegProcess.StartInfo.Arguments = cmdParams;
ffmpegProcess.Start();// start the process
// now that the process is started, we can redirect output to the StreamReader we defined
errorReader = ffmpegProcess.StandardError;
ffmpegProcess.WaitForExit();// wait until ffmpeg comes back
//result = errorreader.ReadToEnd();
}
}
catch (Exception ex)
{
throw new Exception("生成缩略图出错！", ex);
}
}