Advanced search

On other websites (10828)

• Kill child process only after readFile() Node js Electron

  14 May 2021, by Radespy

  I'm using an imported ffmpeg binary ffmpeg-static-electronin an Electron-React app (on Windows Pro 10) and want to delete a saved cropped video and then kill the child process afterwards from my Main process.

  


  The overall aim is to crop a video of the whole screen following capture and then send the cropped video to a renderer.

  


  const fsPromises = require('fs').promises
const ffmpeg = require('ffmpeg-static-electron')
const { execFile } = require("child_process")


ipcMain.on("windoze_capture_screen:video_buffer", async (event, buffer) => {
    const temp_directory =  await fsPromises.mkdtemp(await fsPromises.realpath(os.tmpdir()) + path.sep)
    const capture_screen_video_path = path.join(temp_directory, "screen_capture_video.mp4")

    child_object = execFile(`${ffmpeg.path}`, 

            ['-i', `${capture_screen_video_path}`, '-vf', `crop=${width}:${height}:${x_pos}:${y_pos}`, `${path.join(temp_directory,'cropped_video.mp4')}`])
            
    child_object.on("exit", async () => {

        // child_object.kill()
        console.log("?Killed -1", child_object.killed)
        
        try { 
            databasePayload.video_buffer = await fsPromises.readFile(path.join(temp_directory, "cropped_video.mp4"), {encoding: 'base64'})
            mainWindow.webContents.send("main_process:video_buffer", databasePayload.video_buffer)
        } catch (error) {
            console.log(error)
        } finally {

            // child_object.kill()
            console.log("?Killed - 2", child_object.killed)
            
            // noASAR required to be set to 'true' in order to remove temp directory in build
            process.noAsar = true 
            fs.rmdir(temp_directory, {recursive: true}, (error) => {if (error) {log(error)}})
            process.noASAR = false
            }

            // 3rd scenario
            // child_object.kill()
            console.log("?Killed -3", child_object.killed)   
        })

        // 4th scenario
        console.log("?Killed-4", child_object.killed)   
    })



  


  When running each of these scenarios, I get the following outputs.

  


  Scenario's 1, 2 and 3 - Successfully sends cropped video to renderer but doesn't kill process.

  


  Output:

  


  ?Killed-4 false
?Killed -1 false
[ffmpeg version 3.0.1 Copyright (c) 2000-2016 the FFmpeg developers built with gcc 5.3.0 (GCC).... etc. ]
?Killed-2 false
?Killed -3 false


  


  Scenario 4 - Doesn't crop video

  


  ?Killed-4 true
?Killed -1 true
Command failed: C:\Users\XXX\Desktop\windows-electron-forge\node_modules\ffmpeg-static-electron\bin\win\x64\ffmpeg.exe -i C:\Users\XXX\AppData\Local\Temp\4WgnUw\screen_capture_video.mp4 -vf crop=796:763:462:509 C:\Users\XXX\AppData\Local\Temp\4WgnUw\cropped_video.mp4

[Error: ENOENT: no such file or directory, open 'C:\Users\XXX\AppData\Local\Temp\4WgnUw\cropped_video.mp4'] {
errno: -4058,
code: 'ENOENT',
syscall: 'open',
path: 'C:\\Users\\XXX\\AppData\\Local\\Temp\\4WgnUw\\cropped_video.mp4'
}
?Killed - 2 true
?Killed -3 true


  


  The last scenario has been tried out of desperation.

  


  Question: Where am I going wrong with this ? I suspect it's something to do with ipc between child and parent process but not sure where to place the code.

  


  Any help will be much appreciated !!!

  


• FFMPEG not saving logs when converting to audio format

  2 February, by PUXIII

  The command does not save or even create a file:

  


  ffmpeg -i "video.mp4" -f mp3 "audio.mp3" -vstats_file "log_file.log"


  


  And if you convert to a video file, everything normally creates and writes:

  


  ffmpeg -i "video.mp4" -f mp3 "video.avi" -vstats_file "log_file.log"


  


  Goal: to pull out the time from the log file and bind it to the process bar.

  


  There are no problems with video, everything works. But with the sound does not work.

  


  I tried the command:

  


  ffmpeg -i "video.mp4" -f mp3 "video.avi" >2 "log_file.txt"


  


  But there are other problems popping out. Since I run it all from the Python using the subprocess module.

  


  ffmpegProc = subprocess.Popen(ffmpegCommand, startupinfo=startupinfo, shell=True)


  


  , I can not kill the running process, because it is started with the attribute shell=True, and only the shell is killed.

  


• How to do make a loading screen for ffmpeg using c# asp.net

  1 September 2011, by anthonypliu

  I have this function and where the Debug.WriteLine commands are is where I output the values. How would I get this data to print into a webpage so I can mimic a loading screen? I am calling this function externally through a *.ashx web service file.

  private string ConvertToFLV(string phyicalFilePath)
  
          {
  
              if (Path.GetExtension(phyicalFilePath).Equals(".flv")) return phyicalFilePath;
  
  
  
              var argument = string.Format(@"-i ""{0}"" -vcodec flv -f flv -r 29.97 -s 320x240 -aspect 4:3 -b 300k -g 160 -cmp dct  -subcmp dct  -mbd 2 -flags +aic+cbp+mv0+mv4 -trellis 1 -ac 1 -ar 22050 -ab 56k ""{1}""", phyicalFilePath, Path.ChangeExtension(phyicalFilePath, "flv"));
  
              libfaac -ar 48000 -ab 128k -coder 1 -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -me_method hex -subq 6 -me_range 16 -g 250 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -b_strategy 1 -threads 0 {1}", phyicalFilePath, Path.ChangeExtension(phyicalFilePath, "mp4"));
  
              File.Delete(Path.ChangeExtension(phyicalFilePath, "flv"));
  
  
  
              ProcessStartInfo process = new ProcessStartInfo(ffmpegPhysicalPath, argument);
  
              Process proc = new Process();
  
              float duration = 0.00F, current = 0.00F;
  
              proc.StartInfo = process;
  
              proc.EnableRaisingEvents = false;
  
              proc.StartInfo.UseShellExecute = false;
  
              proc.StartInfo.CreateNoWindow = true;
  
              proc.StartInfo.RedirectStandardOutput = true;
  
              proc.StartInfo.RedirectStandardError = true;
  
  
  
              proc.Start();
  
  
  
              StreamReader d = proc.StandardError;
  
  
  
              do
  
              {
  
                  string s = d.ReadLine();
  
                  if (s.Contains("Duration: "))
  
                  {
  
                      Debug.WriteLine("DURATION: " + s);
  
  
  
                  }
  
                  else
  
                  {
  
                      if (s.Contains("frame="))
  
                      {
  
                          Debug.WriteLine("FRAME: " + s);
  
  
  
                      }
  
                  }
  
              } while (!d.EndOfStream);
  
  
  
  
  
              proc.WaitForExit();
  
  
  
              return Path.ChangeExtension(phyicalFilePath, "flv");