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• Problems with timeout when there is no video source with RTP format in java openCV

  15 février 2019, par Javier Dalmau Fajardo

  I have problems with the timeout when there is no video source with RTP format.

  If I execute the code and there is no video, the program stays waiting in the grabber.Start () function all the time.

  FFmpegFrameGrabber grabber;
  
  try{
  
      Frame img;        
  
      grabber = new FFmpegFrameGrabber("rtp://" + ip + ":1234");
  
      grabber.setOption("stimeout", String.valueOf(5*1000000));
  
      grabber.Start ();
  
      img = grabber.grab();
  
      Java2DFrameConverter converter = new Java2DFrameConverter();
  
  BufferedImage bufferedImag;
  
  bufferedImag = converter.convert(img);
  
      grabber.stop();
  
  }catch (FrameGrabber.Exception ex) {
  
      throw new IOException("Could not open video file ", ex);
  
  }

  As I said before, when the video exists, everything works perfectly, but when there is no video source, the program stays in the grabber.start () and I can not get out of there.

  I would like that when 5 seconds pass, it generates an exception and leaves the grabber.satart () function. I use grabber.setOption("stimeout", String.valueOf(5*1000000)) ; to controlate it but don’t work in RTP.

  I have checked the operation with RTSP video source and the code works perfectly, that is, after 5 seconds it generates an exception ... but I need to control the RTP video source.

  Someone could help me, thanks.

• ruby on rails carrierwave-video ffmpeg AWS

  11 mars 2015, par Joseph Han Nim Jang

  I am trying to create an academic site where users can upload lecture videos and other users can view them - similar to a site like Udemy.

  I am using Carrierwave, Carrierwave-video (for encoding videos), AWS to make this happen. AWS configuration has been done, and it’s working.

  However, I am getting this error. (By the way, I am testing this video feature in a Yelpdemo site, so I am trying to have users upload videos to restaurants for now.)

  rails points the error to @restaurant = Restaurant.new(restaurant_params)

  Errno::ENOENT in RestaurantsController#create

  No such file or directory - ffmpeg

  # POST /restaurants.json
  def create
  @restaurant = Restaurant.new(restaurant_params)

  respond_to do |format|
  
    if @restaurant.save

  This is my video_uploader.rb

  # encoding: utf-8
  
  
  
  class VideoUploader < CarrierWave::Uploader::Base
  
  
  
    include CarrierWave::Video
  
    include CarrierWave::Video::Thumbnailer
  
  
  
    process encode_video: [:mp4]
  
  
  
    include CarrierWave::MiniMagick
  
  
  
    storage :fog
  
  
  
    def store_dir
  
      "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  
    end
  
  
  
     version :thumb do
  
        process thumbnail: [{format: 'png', quality: 10, size: 192, strip: true, logger: Rails.logger}]
  
        def full_filename for_file
  
          png_name for_file, version_name
  
        end
  
    end
  
  
  
      def png_name for_file, version_name
  
        %Q{#{version_name}_#{for_file.chomp(File.extname(for_file))}.png}
  
      end
  
  end

  I have manually (added a file to the model) created video.rb in the model - not sure if this is the right way to do it..

  class Video < ActiveRecord::Base
  
  
  
    attr_accessor :user_id, :video,, :type, :filename, :path, :filesize, :width, :height, :duration, :bit_rate
  
  
  
    belongs_to :restaurant
  
    belongs_to :user
  
  
  
    mount_uploader :video, VideoUploader
  
  end

  in app/views/restaurants/show.html.erb for showing the video. Right now, without the encoding done, I can see like an image of the video. When I right lick and copy the code - it gives me the AWS URL which means AWS configuration is in place

          <p>
  
              <strong>Video:</strong>
  
              &lt;%= video_tag @restaurant.video_url %>
  
          </p>

  I am trying to show videos like this.

  I have downloaded FFMPEG (both ffmpeg-2.6 and SnowLeopard_Lion_Mountain_Yosemite_17) - not sure which one’s the right one.. And I have read somewhere that you need to place FFMPEG in your usr/local/bin -> So do you have to physically place ffmpeg exec file in your respective folder ?

  Need your expert help please.

  Thank you in advance !

• JavaCV pass video frame to imread()

  6 décembre 2017, par Tina J

  I’m trying to use JavaCV for template matching. The demo example is located here. I add all their .jar files to the project. I need to pass a video frame (say video.mp4’s last frame) to imread() instead of it reading the source image from file. How can I do that ?

  String [] arg={"laff.png","template.png"};
  
  FrameGrabber grabber = new FFmpegFrameGrabber("video.mp4");
  
  System.out.println(grabber.getFrameRate());    //returns 0???
  
  
  
  // read in image default colors
  
  Mat sourceColor = imread(args[0]);   // pass last frame of video.mp4 instead of args[0]

  UPDATE : I now can pass [the first] video frame to imread() using the following way (key point is to call start()). So I got the conversion done. Now I need to know how to grab a particular frame number, say the last frame.

  FFmpegFrameGrabber grabber = new FFmpegFrameGrabber("video.mp4");
  
  grabber.start();
  
  System.out.println(grabber.getLengthInTime());
  
  OpenCVFrameConverter.ToMat converter = new OpenCVFrameConverter.ToMat();