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• Putting quotes round a string in C# [duplicate]

  9 décembre 2014, par ADAMPOKE111

  This question already has an answer here :

  • Escape double quotes in string
    
    5 answers
    

  I need help putting two quotes round to strings in this line of code.

  System.Diagnostics.Process.Start("CMD.exe", "\"/C ffmpeg -loop 1 -i input.png -i " + value + " -acodec libvo_aacenc -vcodec h264 -shortest " + value + ".mp4\"");

  I am trying to pass two custom arguments to ffmpeg in CMD.exe, how ever if the file has spaces it fails and does nothing.

  The way to fix this is to put two quotes around it like " + value + ", but that brings up a bunch of errors.
  I’ve tried things like "\"" + value + "\"" but it just brings up a ton of errors.

• C# Problem Reading Console Output to string

  25 septembre 2012, par MoreThanChaos

  i want to launch ffmpeg from my app and retrive all console output that ffmpeg produces. Thing seems obvious, i followed many forum threads/articles like this one but i have problem, though i follow all information included there I seem to end up in dead end.

  String that should contain output from ffmpeg is always empty. I've tried to see where is the problem so i made simple c# console application that only lists all execution parameters that are passed to ffmpeg, just to check if problem is caused by ffmpeg itself. In that case everything work as expected.

  I also did preview console window of my app. When i launch ffmpeg i see all the output in console but the function that should recieve that output for further processing reports that string was empty. When my param-listing app is launched the only thing I see is the expected report from function that gets output.

  So my question is what to do to get ffmpeg output as i intended at first place.

  Thanks in advance
  MTH

• Display a specific string in each frame with ffmpeg

  22 septembre 2020, par Robyc

  I'm creating a video from a set of images like this

  


      ffmpeg -f concat -safe 0 -r 1 -i video_file.txt -crf 0 video_file.mkv


  


  where video_file.txt contains the filepath of the images, which looks like this :

  


      file '/path/to/image1.tif'
    duration 0.5
    file_packet_metadata name=image1_name
    file '/path/to/image2.tif'
    duration 0.5
    file_packet_metadata name=image2_name
    ...


  


  Concat reads all the lines starting with file '...' and correctly creates the output video.

  


  I want that for each frame a specific string appears on screen, e.g. the filename or part of it.

  


  I tried different options but none worked :

  


  

  1. adding -vf drawtext=textfile='path/to/frame.txt to the ffmpeg command

     

     • where frame.txt contains in each line the text I want for each frame.

     


     • This fails because the entire text in the file is displayed over each frame.

     


     


  


  2. adding -vf drawtext=text=%{metadata\\:name} to read the metadata name=image1_name in video_file.txt source here

     

     • this simply displays the string 'name' in the output

     


     • I tried metadata\:name, metadata:name, and metadata:name

     


     


  


  


  How can I display a specific string for each frame ?