def extract_image_from_video(video_input, name_output, timestamps):
    ret = "Error"
    try:
        
        index=0
        select_filter = "-filter:v \"select="
        for ttp in timestamps:                 
            select_filter += "\'lt(prev_pts*TB\,"+str(ttp)+")*gte(pts*TB\,"+str(ttp)+")"
            index=index+1
            
            if(index < len(timestamps)):
                select_filter += " + "
            else:
                select_filter += "\'\""
              
        print('select_filter is: '+ select_filter)
        
        print(video_input)
        print(timestamps)
        print("\n\t Extracting video frame from file {} at timestamps {}\n").format(video_input, timestamps)
        print("exiting")
        
        return ret
    except ValueError:
        return("Oops! error...")