我试图将一些流传输到ffmpeg并捕获它的输出,以便我可以在我的代码中传递另一个流。
这是一个代码示例,它只是在我写入StandardInput.BaseStream
后停止进程继续。
internal class Program
{
private static void Main(string[] args)
{
var inputFile = @"C:\Temp\test.mp4";
var outputFile = @"C:\Temp\test.mp3";
var process = new Process
{
StartInfo = new ProcessStartInfo
{
RedirectStandardInput = true,
RedirectStandardOutput = true,
RedirectStandardError = true,
UseShellExecute = false,
CreateNoWindow = true,
Arguments = "-i - -f mp3 -",
FileName = "ffmpeg.exe"
},
EnableRaisingEvents = true
};
process.ErrorDataReceived += (sender, eventArgs) => Console.WriteLine(eventArgs.Data);
process.Start();
process.BeginErrorReadLine();
using (var input = new FileStream(inputFile, FileMode.Open))
using (var output = new FileStream(outputFile, FileMode.Create))
{
input.CopyTo(process.StandardInput.BaseStream);
process.StandardOutput.BaseStream.CopyTo(output);
}
process.WaitForExit();
Console.WriteLine("done");
Console.ReadLine();
}
}
此示例与此问题的答案几乎相同:https://stackoverflow.com/a/8999542/2277280
我做错了什么? 为什么这个过程不能继续? 具体是ffmpeg吗?
答案 0 :(得分:3)
我必须异步地从stdin和stdout写入和读取以避免死锁。 Wiz和this post的评论让我朝着正确的方向前进!谢谢! 关闭StandardInput以使进程结束也很重要。 否则它仍会等待更多输入,并且stdout保持打开状态,永远不会完成复制。 以下代码在我的场景中完美运行:
private static void Main(string[] args)
{
var inputFile = @"C:\Temp\test.mp4";
var outputFile = @"C:\Temp\test.mp3";
var process = new Process
{
StartInfo = new ProcessStartInfo
{
RedirectStandardInput = true,
RedirectStandardOutput = true,
RedirectStandardError = true,
UseShellExecute = false,
CreateNoWindow = true,
Arguments = "-i - -f mp3 -",
FileName = "ffmpeg.exe"
},
EnableRaisingEvents = true
};
process.ErrorDataReceived += (sender, eventArgs) =>
{
Console.WriteLine(eventArgs.Data);
};
process.Start();
process.BeginErrorReadLine();
var inputTask = Task.Run(() =>
{
using (var input = new FileStream(inputFile, FileMode.Open))
{
input.CopyTo(process.StandardInput.BaseStream);
process.StandardInput.Close();
}
});
var outputTask = Task.Run(() =>
{
using (var output = new FileStream(outputFile, FileMode.Create))
{
process.StandardOutput.BaseStream.CopyTo(output);
}
});
Task.WaitAll(inputTask, outputTask);
process.WaitForExit();
Console.WriteLine("done");
Console.ReadLine();
}