How to use pipe in ffmpeg within c#

问题:

I have 100 jpegs.

I use ffmpeg to encode to a video file which is written to a hard drive.

Is there a way to pipe it directly to a byte/stream?

I am using C# and I am using the process class to initate ffmpeg.

Thanks

回答1:

using System;
using System.Diagnostics;
using System.Drawing;
using System.IO;

namespace PipeFfmpeg
{
    class Program
    {
        public static void Video(int bitrate, int fps, string outputfilename)
        {
            Process proc = new Process();

            proc.StartInfo.FileName = @"ffmpeg.exe";
            proc.StartInfo.Arguments = String.Format("-f image2pipe -i pipe:.bmp -maxrate {0}k -r {1} -an -y {2}",
                bitrate, fps, outputfilename);
            proc.StartInfo.UseShellExecute = false;
            proc.StartInfo.RedirectStandardInput = true;
            proc.StartInfo.RedirectStandardOutput = true;

            proc.Start();

            for (int i = 0; i < 500; i++)
            {
                using (var ms = new MemoryStream())
                {
                    using (var img = Image.FromFile(@"lena.png"))
                    {
                        img.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
                        ms.WriteTo(proc.StandardInput.BaseStream);
                    }
                }
            }            
        }

        static void Main(string[] args)
        {
            Video(5000, 10, "lena.mp4");
        }
    }
}

回答2:

Instead of running ffmpeg process you should directly access ffmpeg library from your code. For example, check out AForge.Net. Among other things it has a ffmpeg managed wrapper. You are intersted in AForge.Video.FFMPEG.VideoFileWriter class, which does exactly that - writes images to video file stream using specified encoder. See online documentation for details.

回答3:

I have found this post few weeks ago when I was looking for answer for my problem. I tried to start ffmpeg process and pass arguments to it but it take sooo long to do everything. At this point I use Xabe.FFmpeg as it doing this out of the box and don't have to worry about ffmpeg executables because have feature to download latest version.

bool conversionResult = await new Conversion().SetInput(Resources.MkvWithAudio)
  .AddParameter(String.Format("-f image2pipe -i pipe:.bmp -maxrate {0}k -r {1} -an -y {2}",bitrate, fps, outputfilename))
  .Start();

回答4:

in case anyone wanted to know. Adding '-' at the end of the arguments will redirect the stream to standard output which can be caught if you subscribe to the OutputDataReceived event of the process class.