獲取C＃中的視頻文件的縮略圖圖像＃

Question

我想要顯示我網站上列出的視頻的縮略圖，我想從視頻中獲取單個幀（從特定時間）並將它們顯示爲縮略圖。

我試試這個http://ramcrishna.blogspot.com/2008/09/playing-videos-like-youtube-and.html，但不工作。

使用.NET C＃可以嗎？

Answer 1

您可以通過編程方式執行FFmpeg來生成縮略圖圖像文件。然後打開圖像文件，然後根據需要使用它。

下面是一些示例代碼：

public static Bitmap GetThumbnail(string video, string thumbnail) 
{ 
    var cmd = "ffmpeg -itsoffset -1 -i " + '"' + video + '"' + " -vcodec mjpeg -vframes 1 -an -f rawvideo -s 320x240 " + '"' + thumbnail + '"'; 

    var startInfo = new ProcessStartInfo 
    { 
     WindowStyle = ProcessWindowStyle.Hidden, 
     FileName = "cmd.exe", 
     Arguments = "/C " + cmd 
    }; 

    var process = new Process 
    { 
     StartInfo = startInfo 
    }; 

    process.Start(); 
    process.WaitForExit(5000); 

    return LoadImage(thumbnail); 
} 

static Bitmap LoadImage(string path) 
{ 
    var ms = new MemoryStream(File.ReadAllBytes(path)); 
    return (Bitmap)Image.FromStream(ms); 
} 

Answer 2

FFmpeg的是可用於在一些位置，以提取視頻幀中合適的工具。 如上所述，或只是利用現有的.NET包裝可以調用ffmpeg.exe（如Video converter for .NET（免費）獲得縮略圖只用一行代碼：

var ffMpeg = new NReco.VideoConverter.FFMpegConverter(); 
ffMpeg.GetVideoThumbnail(pathToVideoFile, thumbJpegStream,5); 

Answer 3

[HttpPost] 
     [Route("UploadImages")] 
     public HttpResponseMessage Post() 
     { 
      HttpResponseMessage response = new HttpResponseMessage(); 
      var httpRequest = HttpContext.Current.Request; 
      if (httpRequest.Files.Count > 0) 
      { 
       var docfiles = new List<string>(); 
       foreach (string file in httpRequest.Files) 
       { 
        var postedFile = httpRequest.Files[file]; 
        var filePath1 = HttpContext.Current.Server.MapPath("~/ImgFolder/" + postedFile.FileName); 

        Stream strm = postedFile.InputStream; 

        CreateThumbnail(strm, postedFile.FileName); 

        Compressimage(strm, filePath1, postedFile.FileName); 


       } 
       response = Request.CreateResponse(HttpStatusCode.Created, docfiles); 
      } 
      else 
      { 
       response = Request.CreateResponse(HttpStatusCode.BadRequest); 
      } 
      return response; 
     } 
     public static void **CreateThumbnail**(Stream sourcePath, string filename) 
     { 
      Image image = Image.FromStream(sourcePath); 
      Image thumb = image.GetThumbnailImage(120, 120,() => false, IntPtr.Zero); 
      var filePath1 = HttpContext.Current.Server.MapPath("~/Thumbnail/" + filename); 

      thumb.Save(filePath1 + filename); 

     } 

     public static void Compressimage(Stream sourcePath, string targetPath, String filename) 
     { 


      try 
      { 
       using (var image = Image.FromStream(sourcePath)) 
       { 
        float maxHeight = 900.0f; 
        float maxWidth = 900.0f; 
        int newWidth; 
        int newHeight; 
        string extension; 
        Bitmap originalBMP = new Bitmap(sourcePath); 
        int originalWidth = originalBMP.Width; 
        int originalHeight = originalBMP.Height; 

        if (originalWidth > maxWidth || originalHeight > maxHeight) 
        { 

         // To preserve the aspect ratio 
         float ratioX = (float)maxWidth/(float)originalWidth; 
         float ratioY = (float)maxHeight/(float)originalHeight; 
         float ratio = Math.Min(ratioX, ratioY); 
         newWidth = (int)(originalWidth * ratio); 
         newHeight = (int)(originalHeight * ratio); 
        } 
        else 
        { 
         newWidth = (int)originalWidth; 
         newHeight = (int)originalHeight; 

        } 
        Bitmap bitMAP1 = new Bitmap(originalBMP, newWidth, newHeight); 
        Graphics imgGraph = Graphics.FromImage(bitMAP1); 
        extension = Path.GetExtension(targetPath); 
        if (extension == ".png" || extension == ".gif") 
        { 
         imgGraph.SmoothingMode = SmoothingMode.AntiAlias; 
         imgGraph.InterpolationMode = InterpolationMode.HighQualityBicubic; 
         imgGraph.DrawImage(originalBMP, 0, 0, newWidth, newHeight); 


         bitMAP1.Save(targetPath, image.RawFormat); 

         bitMAP1.Dispose(); 
         imgGraph.Dispose(); 
         originalBMP.Dispose(); 
        } 
        else if (extension == ".jpg") 
        { 

         imgGraph.SmoothingMode = SmoothingMode.AntiAlias; 
         imgGraph.InterpolationMode = InterpolationMode.HighQualityBicubic; 
         imgGraph.DrawImage(originalBMP, 0, 0, newWidth, newHeight); 
         ImageCodecInfo jpgEncoder = GetEncoder(ImageFormat.Jpeg); 
         Encoder myEncoder = Encoder.Quality; 
         EncoderParameters myEncoderParameters = new EncoderParameters(1); 
         EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, 50L); 
         myEncoderParameters.Param[0] = myEncoderParameter; 
         bitMAP1.Save(targetPath, jpgEncoder, myEncoderParameters); 

         bitMAP1.Dispose(); 
         imgGraph.Dispose(); 
         originalBMP.Dispose(); 

        } 


       } 

      } 
      catch (Exception) 
      { 
       throw; 

      } 
     } 


     public static ImageCodecInfo GetEncoder(ImageFormat format) 
     { 

      ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders(); 

      foreach (ImageCodecInfo codec in codecs) 
      { 
       if (codec.FormatID == format.Guid) 
       { 
        return codec; 
       } 
      } 
      return null; 
     }