process start arguments

Question

when i do the following command into dos it will work fine  ffmpeg -f image2 -i frame d jpg -vcodec mpeg4 -b 800k video avi   When I try to use the process class in c   without the arguments  it loads ffmpeg in a console window then dissapears like usual  However  when I try to use the argument as I do above  formatted exactly the same   it doesn t work  ffmpeg still loads  however since the console window closes so fast I cannot determine what the error is     Process ffmpeg   new Process    ffmpeg StartInfo FileName   path           ffmpeg exe   ffmpeg StartInfo Arguments     -f image2 -i frame d jpg -vcodec mpeg4 -b 800k video avi   ffmpeg Start      Any one know why this is  Why would the command work from dos and then fail to work using c  even when the arguments are exactly the same  I ve used this method before for many things and never encountered this

User · Accepted Answer

Try fully qualifying the filenames in the arguments - I notice you're specifying the path in the FileName part, so it's possible that the process is being started elsewhere, then not finding the arguments and causing an error.

If that works, then setting the WorkingDirectory property on the StartInfo may be of use.

Actually, according to the link

The WorkingDirectory property must be set if UserName and Password are provided. If the property is not set, the default working directory is %SYSTEMROOT%\system32.

User · Answer

Make sure to use full paths  e g  not only  video avi  but the full path to that file   A simple trick for debugging would be to start a command window using cmd  k  lt command gt instead   string ffmpegPath   Path Combine path   ffmpeg exe    string ffmpegParams     -f image2 -i frame d jpg -vcodec           mpeg4 -b 800k C  myFolder video avi   Process ffmpeg   new Process    ffmpeg StartInfo FileName    cmd exe   ffmpeg StartInfo Arguments     k     ffmpegPath         ffmpegParams ffmpeg Start      This will leave the command window open so that you can easily check the output

User · Answer

Very edge case  but I had to use a program that worked correctly only when I specified  StartInfo         RedirectStandardOutput   true    Not specifying it would result in an error  There was not even the need to read the output afterward

User · Answer

Not really a direct answer  but I d highly recommend using LINQPad for this kind of  exploratory  C  programming   I have the following as a saved  query  in LINQPad   var p   new System Diagnostics Process    p StartInfo FileName    cmd exe   p StartInfo Arguments     c echo Foo  amp  amp  echo Bar   p StartInfo RedirectStandardOutput   true  p StartInfo UseShellExecute   false  p StartInfo CreateNoWindow   true  p Start    p StandardOutput ReadToEnd   Dump      Feel free to adapt as needed

User · Answer

To diagnose better  you can capture the standard output and standard error streams of the external program  in order to see what output was generated and why it might not be running as expected   Look up    ProcessStartInfo RedirectStandardError and ProcessStartInfo RedirectStandardOutput    If you set each of those to true  then you can later call process StandardOutput ReadToEnd   and process StandardError ReadToEnd   to get the output into string variables  which you can easily inspect under the debugger  or output to trace or your log file

[c#] process.start() arguments

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