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• Generating a thumbnail from an uploaded video stream ?

  2 juillet 2015, par gd73

  I am building a page for people to upload video files using C#, .NET MVC and Azure. These files are stored in Azure blob storage. I want to generate a thumbnail during upload. But the only solutions I found to generate thumbnails from video are using ffmpeg wrappers and these can only operate on actual files on the filesystem, not streams. Is there a way to capture a still from a stream ? The video is only available as either a blob or a stream, I really can’t store local copies for making thumbnails. Any help would be greatly appreciated !

• ffmpeg based JAVE video conversion taking a long time

  18 novembre 2015, par Deepak

  I am using ffmpeg to convert videos to mp4 format in my application I have used JAVE and Xuggler for the same. My issue is that, video conversions are taking way too much of time. For example, a 50MB video takes almost 2 hrs to complete the video conversion and upload the same. Also, when i play a video, it takes a longer time to play on safari on mac OS than chrome/firefox.

  What are the possible solutions for this ?
  How to optimize the conversion time/video buffering for playing the video faster

• Recording of Full HD 60 FPS videos in C#

  17 mars 2021, par Alexander Naumov

  My application works with a high-speed camera. I am trying to record a videofile using C#.

  


  The task is pretty "simple" : to record the video from the camera. We need to record medium (higher-better) quality videos to save as many details as possible.

  


  

  • Resolution : 1920 x 1080 (FullHD)

  


  • Frames per second (FPS) : 60

  


  • Bitrate : I've started from 10000*1000 (but now I don't know)

  


  • Mediacontainer : MP4, AVI (does not really matter, we just need to
solve our task)

  


  • Codec : also does not matter, we just need speed and quality.

  


  • Maximum size of videofile : 10 GB/hour

  


  


  Framerate of the camera can be changed during the recording by the camera itself (not by user), so it's necessary to have something like timestamps for every frame or anything else.

  


  The problem is not fast enough recording.
Example : using AForge libs, generated pictures ("white" noise), duration of test videos is 20 seconds.

  


  Duration of video creating using different codecs (provided by AForge) :

  


  

  • Codec : MPEG4, Time : 33,703

  


  • Codec : WMV1, Time : 45,338

  


  • Codec : WMV2, Time : 45,530

  


  • Codec : MSMPEG4v2, Time : 43,775

  


  • Codec : MSMPEG4v3, Time : 44,390

  


  • Codec : H263P, Time : 38,894

  


  • Codec : FLV1, Time : 39,151

  


  • Codec : MPEG2, Time : 35,561

  


  • Codec : Raw, Time : 61,456

  


  


  Another libs we've tried is not satisfied us.
Accord.FFMPEG is slow because of strange inner exceptions.
EmguCV.FFMPEG has no timestamps, therefore it creates corrupted video.

  


  Recording the video to the SSD drive did not give us any visible acceleration.

  


  Google search gives no clear examples or modern solutions to solve this task. That's the main reason to write here.

  


  There is a code sample of our test :

  


  private static void AForge_test()
    {
        Console.WriteLine("AForge test started...");
        unsafe
        {
            Stopwatch watch = new Stopwatch();

            Console.WriteLine("FPS: {0}, W:{1}, H:{2}, T:{3}", fps, w, h, time);

            AForge.Video.FFMPEG.VideoCodec[] codecs = (AForge.Video.FFMPEG.VideoCodec[]) Enum.GetValues(typeof(AForge.Video.FFMPEG.VideoCodec));

            for(int k = 0; k < codecs.Length; k++)
            {
              /*  if (codecs[k] != VideoCodec.MPEG4)
                    continue;*/
                try
                {
                    watch.Restart();

                    Random r2 = new Random(200);
                    AForge.Video.FFMPEG.VideoFileWriter vw = new AForge.Video.FFMPEG.VideoFileWriter();
                    string name = String.Format("E:\\VideosHDD\\AForge_test_{0}_mid.avi", Enum.GetName(typeof(AForge.Video.FFMPEG.VideoCodec), codecs[k]));
                    vw.Open(name, w, h, fps, codecs[k], 10000 * 1000);

                    for (int i = 0; i < frames; i++)
                    {
                        vw.WriteVideoFrame(bmps[i%N]);
                    }

                    vw.Close();
                    vw.Dispose();

                    watch.Stop();

                    Console.WriteLine("Codec: {0}, Time: {1:F3}", Enum.GetName(typeof(AForge.Video.FFMPEG.VideoCodec), codecs[k]), watch.ElapsedMilliseconds / 1000d);
                }
                catch(Exception ex)
                {
                    Console.WriteLine("Error " + codecs[k].ToString());
                }

            }
            
        }

        Console.ReadKey();
    }


  


  Additional :

  


  

  1. We are ready to use not-for-free solutions, but free is preferable.

  


  2. One of the supposed reasons for low recording speed : (x86) building of applications. I tried so hard to find x64 Aforge building but failed in this. We really don't know is there any influence of application architecture on recording speed.

  


  


  I am ensured that I don't know all the background of video recording and another "little" thing, so I would be very pleased to solutions with clear explanations.