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• How easy is it to create a YouTube to MP3 application using yt-dlp and ffmpeg ?

  26 juin 2022, par fowlis

  I was thinking I could automate the process of downloading a video and converting it to mp3 (or other formats).
  
Instead of doing the process myself (which doesn't take that long and isn't too much hassle), which looks something like this :
  
• yt-dlp https://www.youtube.com/watch?v=dQw4w9WgXcQ
  
• wait for download then (find and) rename file to something simpler for next command
  
• ffmpeg -i video.mp4 video.mp3

  

  


  I thought I could turn it into a simple JS (or other language) program instead, where it :
  

  


  

  1. Asks for link and what format I want it in

  


  2. Downloads the video

  


  3. Renames it (not sure how easy this is)

  


  4. Turns it into requested format

  


  5. Opens file location

  


  


  If something like this is possible, please let me know some things I should know since I've never written a windows app before, and some general guidance for how I could do this.

  
I apologise if questions like this aren't exactly allowed on this site, its my first time posting too.
  
Thanks in advance !

  


• Execute my PowerShell script does not work via my C# application

  15 février 2024, par Nixir

  I'm currently working on IP cameras for my job, but I'm just starting out because I've never done anything like this before.
The aim is very simple, to start recording a specific camera via a user action, and to stop the same camera via another user action.
To achieve this, I looked for several solutions and finally decided to use FFMPEG and two Powershell scripts.

  


  The first starts recording using FFMPEG and stores the process PID in a .txt file.

  


  StartRec.ps1

  


  #Paramètres de la caméra IP
$cameraIP = $args[0]
$port = $args[1]
$username = $args[2]
$password = $args[3]

$ipfile = ${cameraIP} -replace "\.", ""
$namefile = "video_"+$ipfile+"_"+(Get-Date -Format "ddMMyyyy_HHmmss") + ".mp4"
$namepidfile = "PID_"+$ipfile+".txt"

# URL du flux vidéo de la caméra (exemple générique, adaptez-le à votre caméra)
$videoStreamUrl = "rtsp://${username}:${password}@${cameraIP}:${port}/videoMain"

# Répertoire de sortie pour la vidéo enregistrée
$outputDirectory = "C:\OutputDirectory"

# Chemin complet du fichier de sortie (nom de fichier avec horodatage actuel)
$outputFile = Join-Path $outputDirectory (${namefile})

# Commande FFmpeg pour enregistrer le flux vidéo en arrière-plan
$ffmpegCommand = "ffmpeg -rtsp_transport tcp -i `"$videoStreamUrl`" -c:v copy `"$outputFile`"" 

# Démarrer FFmpeg en arrière-plan
$process = Start-Process -FilePath "cmd.exe" -ArgumentList "/c $ffmpegCommand" -PassThru

$cheminFichier = Join-Path $outputDirectory $namepidfile

if (-not (Test-Path $cheminFichier)) {
    # Le fichier n'existe pas, créer le fichier
    New-Item -ItemType File -Path $cheminFichier -Force
    Write-Host "Fichier créé : $cheminFichier"
} else {
    Write-Host "Le fichier existe déjà : $cheminFichier"
}

Start-Sleep -Seconds 5

$processId = Get-WmiObject Win32_Process -Filter "Name='ffmpeg.exe'" | Select-Object -ExpandProperty ProcessId

# Enregistrez le PID dans un fichier
$process.Id | Out-File $cheminFichier

Write-Host "Enregistrement démarré. PID du processus : $($processId)"


  


  The second reads the contents of this .txt file, stores it in a variable as a PID and stops the process via its Id, then closes the command window associated with this process (which tells the camera that the recording is finished).

  


  StoptRec.ps1

  


  $cameraIP = $args[0]
$ipfile = ${cameraIP} -replace "\.", ""
$namepidfile = "PID_"+$ipfile+".txt"
$outputDirectory = "C:\OutputDirectory"
$cheminFichier = Join-Path $outputDirectory $namepidfile

$pidcontent = Get-Content $cheminFichier -Raw 
if (-not $pidContent) {
    Write-Host "Erreur : Le fichier PID est vide. Assurez-vous que l'enregistrement est démarré."
    exit
}

$processId  = $pidContent.Trim() -as [int]

if (-not $processId) {
    Write-Host "Erreur : Impossible de convertir le contenu du fichier PID en entier."
    exit
}

Get-Process -Id $processId

Stop-Process -Id $processId -PassThru | Foreach-Object { $_.CloseMainWindow() }

Write-Host "Enregistrement arrêté pour le processus PID $processId"
Start-Sleep -Seconds 15


  


  The problem is that they work, except in one case that I'll explain :
First, I tried to run them via PowerShell, the recording starts up and the script works as expected, as does the shutdown. My final file is usable.
I then performed C# actions in my Controller, which calls and executes these scripts :

  


  The action that calls StartRec.ps1

  


          public void startRecordingCam1(string ipAddress)
        {
            string ps1File = @"C:\OutputDirectory\StartRec.ps1";
            string cameraIP = "Camera IP Adress";
            string port = "88";
            string username = "Username";
            string password = "Password";

            Process process = Process.Start(new ProcessStartInfo
            {
                FileName = "powershell.exe",
                Arguments = $"-NoProfile -ExecutionPolicy Bypass -File \"{ps1File}\" \"{cameraIP}\" \"{port}\" \"{username}\" \"{password}\"",
                UseShellExecute = false,
                RedirectStandardInput = true
                //CreateNoWindow = true
            });
        }


  


  The action that calls StopRec.ps1

  


         public void stopRecording(string ipAddress)
        {
            string ps1File = @"C:\Projet Valentin\CameraTest\StopRec_Csharp.ps1";
            string cameraIP = "10.0.1.10";

            ProcessStartInfo startInfo = new ProcessStartInfo()
            {
                FileName = "powershell.exe",
                Arguments = $"-NoProfile -ExecutionPolicy ByPass -File \"{ps1File}\" \"{cameraIP}\" ",
                UseShellExecute = true
            };
            Process.Start(startInfo);
        }


  


  When I run the two scripts via these actions, StartRec.ps1 works well, but StopRec.ps1 doesn't work completely : the process is stopped, but the command window isn't closed, so camera recording continues (despite the end of the process).
As both scripts worked perfectly when launched with Powershell, but not with the C# application, I tried several combinations of "Start-Stop" with "PowerShell/C#".

  


  If I run StartRec.PS1 with the C# application and StopRec.PS1 with PowerShell, it works.
If I run StartRec.PS1 with PowerShell and StopRec.PS1 with the C# application, it works.
If I run StartRec.PS1 with PowerShell and StopRec.PS1 with PowerShell, it works.
The only case that doesn't work is when I run both via the C# application

  


  One thing I can add that I discovered while debugging is that this :
Stop-Process -Id $processId -PassThru | Foreach-Object { $_.CloseMainWindow() }

  


  Returns false in the only case where it doesn't work, and true in all other cases

  


  That's all the details I can give you, thanks for your help !

  


• How to trim a video using FFmpeg in Objective-C for iOS application

  13 juillet 2015, par AnujAroshA

  I am trying to implement a sample iOS application that can trim a bundled video (.mp4) using FFmpeg library in Objective-C environment.

  I used this script to compile and build the FFmpeg for iOS. Those libraries was added to the project but now I’m not sure how to continue it. How can I find which function do the trim behaviour and what are the supportive codecs and etc.

  I am interesting do achieve this with out any wrapper but directly accessing the library functions. How can I do this ?

  Update : 1

  I believe following code snippet will contain the input video file details in a stream

  NSString *filePath = [[NSBundle mainBundle] pathForResource:@"KeseMase" ofType:@".mp4"];
  
  
  
  AVInputFormat *inputFormat = av_find_input_format([@"mp4" UTF8String]);
  
  
  
  const char *utf8FilePath = [filePath UTF8String];
  
  
  
  avformat_open_input(&pFormatCtx, utf8FilePath, inputFormat, nil);

  Or does it contain only the header information of the video file ?

  Update : 2

  With following code, I was able to convert input video to a stream of AVPacket and store them in a NSMutableArray

  - (BOOL)readFrameIntoPacket:(AVPacket *)packet error:(NSError *__autoreleasing *)error
  
  {
  
      BOOL continueReading = YES;
  
  
  
      int frameReadValue = av_read_frame(pFormatCtx, packet);
  
  
  
      if (frameReadValue == 0)
  
      {
  
          NSLog(@"%s - %d # Read next frame", __PRETTY_FUNCTION__, __LINE__);
  
          continueReading = YES;
  
  
  
          NSValue *value = [NSValue valueWithBytes:&packet objCType:@encode(AVPacket)];
  
          [srcPktArr addObject:value];
  
      }
  
      else
  
      {
  
          continueReading = NO;
  
          av_free_packet(packet);
  
      }
  
      return continueReading;
  
  }

  Tasks remain to solve the question are :

  1.) How to use those AVPackets to and write a Video file

  2.) How to give a start time and end time and write only that part to a video file

  Update : 3

  Okay... then I try to write those packets to an out put file like below

  - (BOOL)writePacket:(AVPacket *)packet error:(NSError *__autoreleasing *)error
  
  {
  
      int writeValue = av_write_frame(outputContext, packet);
  
  
  
      if (writeValue == 0)
  
      {
  
          return YES;
  
      }
  
      else if (writeValue == 1)
  
      {
  
          return YES;
  
      }
  
      else
  
      {
  
          return NO;
  
      }
  
  }

  and ended up with following error

  [mp4 @ 0x1c04a200] Invalid packet stream index : 17467852

  Update : 4

  Okay guys, I get this far.