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• Events after FFmpeg in Cmd command is completed in C#

  30 juin 2017, par Манаф Иракский

  I am creating windows form application using C# to manage cmd arguments of FFMPEG, also, I am using FileWatcher, my application as long as its running after clicking the button "start watching" is will watch if any new file landed in the folder, its will open CMD.exe and the argument will use FFMPEG to convert this Video file. its working but the issue is my C# application sends the command to cmd and thats it but I want to handle other tasks like if FFMPEG completed the task delete the original file ? how I can determine in my app thats CMD command completed and then start next task. here is my cod

  namespace WindowsFormsApplication1
  
  public partial class Form1 : Form
  
  public Form1()
  
  InitializeComponent() ;
  

      private void button1_Click(object sender, EventArgs e)
  
      {
  
  
  
          FileSystemWatcher watcher = new System.IO.FileSystemWatcher();
  
          watcher.Path = @"MY PATH";
  
          watcher.NotifyFilter = NotifyFilters.LastWrite;
  
          watcher.Filter = "*.*";
  
          watcher.Changed += new FileSystemEventHandler(OnChanged);
  
          watcher.EnableRaisingEvents = true;
  
  
  
  
  
      }
  
  
  
      private void fileSystemWatcher1_Changed(object sender, System.IO.FileSystemEventArgs e)
  
      {
  
  
  
  
  
      }
  
      private void OnChanged(object source, FileSystemEventArgs e)
  
      {
  
  
  
           DirectoryInfo d = new DirectoryInfo(InPath .Text );
  
          FileInfo[] Files = d.GetFiles("*.*");
  
          string str = "";
  
          foreach (FileInfo file in Files)
  
          {
  
              str = str + file.Name;
  
          }
  
  
  
          var strout = Path.GetFileNameWithoutExtension(str);
  
          string strCmdText;
  
          strCmdText = @"/C ffmpeg.exe -i X.mp4 -Vcodec X Xout.mp4"; /// this is just argument example 
  
          System.Diagnostics.Process.Start("CMD.exe", strCmdText);
  
  
  
  
  
      }
  
  
  
  
  
  
  
      private void Form1_Load(object sender, EventArgs e)
  
      {
  
  
  
  
  
  
  
      }
  
  
  
  }

• Compression of a video with constant background

  28 juin 2017, par Spirou003

  (sorry if my english is bad, I can read it but I don’t write it quite well...)

  I want to compress some videos, which have two particularities :

  • there is a background that covers 90% of the area, during the whole video
  • most of the others elements can be separately described by a picture in move

  My videos are like this one, and don’t have audio. As you can see, almost everything can be described only by using a fixed background, few small images in move, plus a noise. Moreover, this noise will be almost nul and then an entropic coding would be very efficient. I think it will produce tiny files (< 5 Mo) even if the duration is in hours, a result that is very appreciable since I have actually recorded 30h of game (actual size is 3 Go).

  Is there any way to get new video files, that benefit of these informations ? If yes, what are the implication of a such encoding for watching these videos with Windows Media Player, or for usage with ffmpeg ?

  I searched with Google after anything that can help me, but I don’t know which keyword I can use for this, then I didn’t found anything usefull :-(

  Thanks in advance :-)

  PS : another example, the video is accelerated but shows the interesting moves

• How to do Slow Motion video in IOS

  4 mai 2022, par 2vision2

  I have to do "slow motion" in a video file along with audio, in-between some frames and need to store the ramped video as a new video.

  &#xA;&#xA;

  Ref : http://www.youtube.com/watch?v=BJ3_xMGzauk (watch from 0 to 10s)

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  From my analysis, I've found that AVFoundation framework can be helpful.

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  Ref :&#xA;http://developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/00_Introduction.html

  &#xA;&#xA;

  Copy and pasted from the above link :

  &#xA;&#xA;

  "&#xA;Editing&#xA;AV Foundation uses compositions to create new assets from existing pieces of media (typically, one or more video and audio tracks). You use a mutable composition to add and remove tracks, and adjust their temporal orderings. You can also set the relative volumes and ramping of audio tracks ; and set the opacity, and opacity ramps, of video tracks. A composition is an assemblage of pieces of media held in memory. When you export a composition using an export session, it's collapsed to a file.&#xA;On iOS 4.1 and later, you can also create an asset from media such as sample buffers or still images using an asset writer.

  &#xA;&#xA;

  "

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  Questions :&#xA;Can I do " slow motion " the video/audio file using the AVFoundation framework ? Or Is there any other package available ? If i want to handle audio and video separately, please guide me how to do ?

  &#xA;&#xA;

  Update : : Code For AV Export Session :

  &#xA;&#xA;

   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *outputURL = paths[0];
    NSFileManager *manager = [NSFileManager defaultManager];
    [manager createDirectoryAtPath:outputURL withIntermediateDirectories:YES attributes:nil error:nil];
    outputURL = [outputURL stringByAppendingPathComponent:@"output.mp4"];
    // Remove Existing File
    [manager removeItemAtPath:outputURL error:nil];
    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:self.inputAsset presetName:AVAssetExportPresetLowQuality];
    exportSession.outputURL = [NSURL fileURLWithPath:outputURL]; // output path;
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;
    [exportSession exportAsynchronouslyWithCompletionHandler:^(void) {
        if (exportSession.status == AVAssetExportSessionStatusCompleted) {
            [self writeVideoToPhotoLibrary:[NSURL fileURLWithPath:outputURL]];
            ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
            [library writeVideoAtPathToSavedPhotosAlbum:[NSURL fileURLWithPath:outputURL] completionBlock:^(NSURL *assetURL, NSError *error){
                if (error) {
                    NSLog(@"Video could not be saved");
                }
            }];
        } else {
            NSLog(@"error: %@", [exportSession error]);
        }
    }];


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