c# - Emgu CV Get All Frames From Video File - Stack Overflow

08/06/13

c# - Emg u CV g et al l fr ames fr om vi deo fil e - Stack Over fl ow

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Emgu CV get all frames from video file

I would like to ask you to help me with getting all the frames from video file using Emgu CV. I know I can use Capture  class and its QueryFrame()  method, but this only returns one frame. What is the easiest way to get all the frames? (and save it for example to Image[] ) I need all the frames to do some more processing (to be more specific: key frame extraction for video summarization). Thanks ha nks a lot for your help. c#

vid vi deo

emgucv

asked Dec 12 '11 at 10:34 om 46 3 8

2 Answers Answers See my answer here for reference Emgu Capture plays video super fast But this should do as you ask I've used a list to store the images you can use an array but you will need to know how big your your avi file is.

Timer My_Time = new Timer(); int  FPS = 30 30; ; List> >> image_array  image_array = new List>(); Capture _capture;  _capture; public Form1() { InitializeComponent();

  }

 //Fram e Rate My_Timer.Interval = 1000 / FPS;  FPS ; My_Timer.Tick += new EventHandler(My_Timer_Tick); My_Timer.Start() _capture = new Capture("test.avi" "test.avi"); );

private void My_Timer_Tick(object sender,  sender, EventArgs e)  e ) {

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08/06/13

c# - Emgu CV get all frames from video file - Stack Overflow {    

imageBox.Image = _capture.QueryFrame(); image_array.Add (_capture.QueryFrame(). Copy()); } else { My_Timer.Stop();

{ } This was designed to allow playback of the video file at a responsible rate but as your simply converting you could use the Application.Idle method just as easily like this...

List> image_array = new List>(); Capture _capture; public Form1() { InitializeComponent();

 

 //Fram e Rate _capture = new Capture("test.avi"); Application.Idle += ProcessFrame;

} private void ProcessFrame(object sender, EventArgs arg) { Image frame = _capture.QueryFrame(); if (frame != null) {   image_array.Add (frame.Copy()); } else { Application.Idle -= ProcessFrame;  // tre at as end of file }

} You will have to be careful of the end of the file error you will receive an error. You could always use a try catch statement to catch the specific error it will give instead of simply terminating conversion. If you use to use an image array you will have to loop through the file incrementing a variable and counting the frames and then create the image array before converting the video file to an array.

[EDIT]

 As requested th is is a method version of r etrieving a ll frames from a video file I have not tested this on a large video file as I expect that the program would crash since it will require a lot of memory.

08/06/13

c# - Emgu CV get all frames from video file - Stack Overflow

private List> GetVideoFrames(String Filename) { List> image_array = new List>(); Capture _capture = new Capture(Filename);

 

bool Reading = true; while (Reading) { Image frame = _capture.QueryFrame(); if (frame != null) { image_array.Add (frame.Copy()); } else { Reading = false; } }

 

return image_array;

}  Alternatively I realise you may wish to record say 10 se conds of video from a webcam so this method will do that, I used a Stopwatch as the the while loop prohibits the use of a timer unless your multi threading the application

private List> GetVideoFrames(int Time_millisecounds) { List> image_array = new List>(); System.Diagnostics.Stopwatch SW = new System.Diagnostics.Stopwatch ();

 

bool Reading = true; Capture _capture

Capture();

08/06/13

c# - Emgu CV get all frames from video file - Stack Overflow while (Reading) { Image frame = _capture.QueryFrame(); if (frame != null) { image_array.Add (frame.Copy()); if (SW.ElapsedMilliseconds >= Time_millisecounds) Reading = false; } else { Reading = false; } }

 

return image_array;

}

and this would be called like this: List> Image_Array = GetVideoFrames(10000);  //10 S ecoun ds

Hope this helps, Cheers, Chris edited Jan 9 '12 at 16:55

answered Dec 12 '11 at 14:56 Chris 1,747

6 13

Thanks, I just don't want to use it in Application.Idle . I simply want to have a function that I can call whenever I want and it returns me list of Image frames from given video input. – tom Jan 6 '12 at 20:17 Hi I've added to code in a method that you could call, I hope this is what your after if no let me know Cheers – Chris Jan 9 '12 at 17:01

Even i faced the same issue.So i initialised another timer and provided the video save code in there.And this timer is enabled only when the record button[The button on the form which on click record the video] is clicked.Now i can capture video but the audio is not getting recorded. answered Nov 10 '12 at 9:51  Ahammed 31 2

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