There are many cases where one need to extract frames from video irrespective of its length. With the given function one can retrieve the desired number of frames per second.

    ArrayList<Bitmap> frameList; 
        String absolutePath; 

      /* MediaMetadataRetriever class is used to retrieve meta data from methods. */
        MediaMetadataRetriever retriever = new MediaMetadataRetriever();

        try { 
        //path of the video of which you want frames
        retriever.setDataSource(absolutePath);
         }catch (Exception e) {
         System.out.println("Exception= "+e);
         } 

        // created an arraylist of bitmap that will store your frames 
        frameList = new ArrayList<Bitmap>(); 

        String duration = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION); 
        int duration_millisec = Integer.parseInt(duration); //duration in millisec
        int duration_second = duration_millisec / 1000;  //millisec to sec.
        int frames_per_second = 2;  //no. of frames want to retrieve per second
        numeroFrameCaptured = frames_per_second * duration_second; 

        for (int i = 0; i < numeroFrameCaptured; i++) 
        {
        //setting time position at which you want to retrieve frames 
         frames.add(retriever.getFrameAtTime(5000*i) )
        }