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• Accord.Video.FFMpeg : Problem of duration difference between recording time and video time

  5 mars 2020, par ckrby

  I want to save the footage I get from the webcam as a video in webM (Vp8) format. I use the Accord library. But when recording, there is almost 2-3 times the difference between the time spent and the video time. The code I use and some debug outputs are below.

  Accord.Video.FFMpeg 3.8.2-Alpha (double pts/dts bug fixed version)
  Video Save Format : VP8 (.WebM)

  Record Start Settings :

  videoCodec = VideoCodec.Vp8;    
  
  bitrate : 1250000   
  
  framerate :10   
  
  height :720 
  
  width: 1280 
  
  videoSource.VideoResolution: 1280x720, 30 fps (30 max fps), 24 bpp  
  
  FileWriter.BitRate = bitRate;   
  
  FileWriter.FrameRate = new Accord.Math.Rational((int)framerate );   
  
  FileWriter.Width = width;   
  
  FileWriter.Height = height; 
  
  FileWriter.VideoCodec = videoCodec; 
  
  FileWriter.Open(FileName);  
  
  _recording = true;  
  
  StartTimeStamp = DateTime.Now;  

  newFrame Event

  private void VideoSourcePlayer1_NewFrame(object sender, ref Bitmap image)
  
  {
  
      if (_recording)
  
      {
  
          try
  
          {
  
              Bitmap CurrentBitmap = image;
  
              DateTime CurrentTimeStamp = DateTime.Now;
  
              TimeSpan CurrentTimeSpan = StartTimeStamp - CurrentTimeStamp;
  
              Console.WriteLine("Video Write Timespan: " + CurrentTimeSpan.ToString());
  
              FileWriter.WriteVideoFrame(CurrentBitmap, CurrentTimeSpan);
  
              // FileWriter.WriteVideoFrame(image);  
  
          }
  
          catch (Exception ex)
  
          {
  
              Console.WriteLine("VideoSourcePlayer1_NewFrame catch: " + ex.Message);
  
          }
  
      }
  
  }

  Note : It is the same issue with timespan or without timespan writing.

  In the 122 second (02.02 min) period, 50 seconds of video recording is created. I couldn’t solve it.

  Little Part of the debug output :

  Video Write Timespan : -00:01:55.4107365
  pts:4,730000e+004 pts_time:47,3 dts:4,730000e+004 dts_time:47,3 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:55.6136263
  pts:4,740000e+004 pts_time:47,4 dts:4,740000e+004 dts_time:47,4 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:55.8354960
  pts:4,750000e+004 pts_time:47,5 dts:4,750000e+004 dts_time:47,5 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:56.5161088
  pts:4,760000e+004 pts_time:47,6 dts:4,760000e+004 dts_time:47,6 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:56.7309841
  pts:4,770000e+004 pts_time:47,7 dts:4,770000e+004 dts_time:47,7 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:56.9758413
  pts:4,780000e+004 pts_time:47,8 dts:4,780000e+004 dts_time:47,8 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:57.1947200
  pts:4,790000e+004 pts_time:47,9 dts:4,790000e+004 dts_time:47,9 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:57.4375834
  pts:4,800000e+004 pts_time:48 dts:4,800000e+004 dts_time:48 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:01:57.5804983

  The last two outputs :

  Video Write Timespan : -00:02:02.7505463
  pts:5,000000e+004 pts_time : 50 dts:5,000000e+004 dts_time : 50 duration:1,000000e+002 duration_time:0,1
  Video Write Timespan : -00:02:02.9884038
  pts:5,010000e+004 pts_time : 50,1 dts:5,010000e+004 dts_time : 50,1 duration:1,000000e+002 duration_time:0,1

  Why is there a difference between timespan and dts/pts time ? Could the problem be due to this ?

  Note : When I set the framerate to 30 ; Another process 95 seconds (1.35 min) recording time is 16 seconds in the video.

  As the frame rate increases, the length of the video gets shorter and
  shorter than the actual value it should be.

  Output :

  Video Write Timespan : -00:01:35.1086178
  pts:1,606700e+004 pts_time : 16,067 dts:1,606700e+004 dts_time : 16,067 duration:3,300000e+001 duration_time:0,033
  Video Write Timespan : -00:01:35.2565302
  pts:1,610000e+004 pts_time : 16,1 dts:1,610000e+004 dts_time : 16,1 duration:3,300000e+001 duration_time:0,033
  Video Write Timespan : -00:01:35.3984494
  pts:1,613300e+004 pts_time : 16,133 dts:1,613300e+004 dts_time : 16,133 duration:3,300000e+001 duration_time:0,033

  So the video duration is like dts_time. Why is the video duration not
  value of timespan time, I still can’t find it ??

  Soory for my bad english & expression,

• Accord.Video.FFMPEG creates very low quality video

  11 février 2021, par Кирилл Малышев

  I use Accord.Video.FFMPEG to create a video of 200 images with the H264 codec. For some reason, the video is very poor quality. Its size is less than 1MB. When choosing VideoCodec.Raw, the quality is high, but I am not happy with the huge size.

  



  I do something like this

  



  using (var vFWriter = new VideoFileWriter())
{
    vFWriter.Open(video_name, 1920, 1080, 24, VideoCodec.H264);
    for (int i = 0; i < 200; ++i)
    {
        var img_name_src = ...
        using (Bitmap src_jpg = new Bitmap(img_name_src))
        {
            vFWriter.WriteVideoFrame(src_jpg);
        }
    }
    vFWriter.Close();
}


  



  When I run the program, messages appear :

  



  [swscaler @ 06c36d20] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 06e837a0] deprecated pixel format used, make sure you did set range correctly
[avi @ 06c43980] Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead.
[avi @ 06c43980] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.


  



  I don’t know if they affect something.

  



  It looks like 1 frame :

  



  

  



  This is the frame from the video :

  



  

  



  How to fix it ?

  



  Is there any other way in C# to create a video from individual frames ?

  


• In the using directive "using Accord.Video.FFMPEG", FFMPEG does not exist in the name space

  15 septembre 2019, par StewartMetcalfe

  I am building an Azure Function in Visual Studio to convert a videos frames to images. I’m using the VideoFileReader class from Accord.Video.FFMPEG class. The code works on my machine but when trying to build this as an Azure Function Project, the using directive Accord.Video.FFMPEG errors.
  And subsequently the type VideoFileReader can not be found.

  I have tried re-installing the Accord, Accord.Video and Accord.Video.FFMPEG NuGet packages.

  using System.IO;
  
  using Microsoft.Azure.WebJobs;
  
  using Microsoft.Extensions.Logging;
  
  using Accord;
  
  using Accord.Video;
  
  using Accord.Video.FFMPEG;
  
  
  
  namespace ConvertVideo
  
  {
  
      public static class Function1
  
      {
  
          [FunctionName("Function1")]
  
          public static void Run([BlobTrigger("videos/{name}", Connection = "AzureWebJobsStorage")]Stream myBlob, string name, ILogger log)
  
          {
  
              log.LogInformation($"C# Blob trigger function Processed blob\n Name:{name} \n Size: {myBlob.Length} Bytes");
  
  
  
              //start a new videoFileReader
  
              using (var vFReader = new VideoFileReader())
  
              {
  
                  //open the video
  
                  vFReader.Open(name);
  
                  //get the framerate
  
                  double frameRate = vFReader.FrameRate.ToDouble();
  
                  //more code which converts a frame to jpg
  
              }
  
          }   
  
      }
  
   }