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• fftools/ffprobe : Fix hypothetical stack buffer overflow

  31 mars, par Andreas Rheinhardt

  fftools/ffprobe : Fix hypothetical stack buffer overflow
  It can't really happen, because no currently used pixel format
  
  has a name exceeding the size of the buffer.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] fftools/ffprobe.c

• Uploading videos on rails website

  16 mai 2017, par Dinukaperera

  I am trying to let my users upload videos on my website(not deployed yet, testing locally). I have it set up in a manner where if the "user information" gets saved, it will take them to the "root_path", which is the homepage. If the user information is not saved, it will render the form again. Before I added the video upload feature, all the information got saved and everything worked well, but after adding the feature, it keeps rendering the same form over and over again since the information is not getting saved. How do I check what’s wrong ? The command line gives me this error :

  The user information form partial :
  `

  <%= simple_form_for @userinfo do |f| %>
  
    <%= f.input :name, label: 'Full name', error: 'Full name is mandatory' %>
  
    <%= f.input :username, label: 'Username', error: 'Username is mandatory, please specify one' %>
  
    <%= f.input :school, label: 'Name of college' %>
  
    <%= f.input :gpa, label: 'Enter GPA' %>
  
    <%= f.input :email, label: 'Enter email address' %>
  
    <%= f.input :number, label: 'Phone number' %>
  
    <%= f.file_field :video %>
  
    <%= f.button :submit %>
  
  <% end %>

  `

  My user controller (This is the user information controller, does not control user email and password. I’m using the devise gem for user sign in, sign out, and sign up) :`

  class UsersController < ApplicationController
  
      def index
  
      end
  
  
  
      def show
  
      end
  
  
  
      def new
  
          @userinfo = User.new
  
      end
  
  
  
      def create
  
          @userinfo = User.new(user_params)
  
          if @userinfo.save
  
            redirect_to root_path
  
          else
  
            render 'new'
  
          end
  
      end
  
  
  
      def edit
  
      end
  
  
  
      def update
  
      end
  
  
  
      def destroy
  
      end
  
  
  
      private
  
          def user_params
  
              params.require(:user).permit(:name, :username, :email, :number, :school, :gpa, :major, :video)
  
          end
  
  end

  `

  This is the user model (usermain is the model related to user password and email. The user information in the user model belongs to the usermain) : `

  class User < ActiveRecord::Base
  
      belongs_to :usermain
  
  
  
      has_attached_file :video, styles: {:video_show => {:geometry => "640x480",:format => 'mp4'},:video_index => { :geometry => "160x120", :format => 'jpeg', :time => 10}}, :processors => [:transcoder]
  
      validates_attachment_content_type :video, content_type: /\Avideo\/.*\Z/
  
  end

  `

  This is the migration file that creates the user information table :`

  class CreateUsers < ActiveRecord::Migration
  
    def change
  
      create_table :users do |t|
  
        t.string :name
  
        t.string :username
  
        t.string :email
  
        t.string :number
  
        t.string :school
  
        t.string :gpa
  
        t.string :major
  
  
  
        t.timestamps null: false
  
      end
  
    end
  
  end

  This is adding the "video" field to the above created user information table:

  class AddAttachmentVideoToUsers < ActiveRecord::Migration
  
    def self.up
  
      change_table :users do |t|
  
        t.attachment :video
  
      end
  
    end
  
  
  
    def self.down
  
      remove_attachment :users, :video
  
    end
  
  end

  `

  I also have paperclip and ffmpeg installed. When I say installed, it’s literally just that. I’m not sure if I have to manipulate paperclip or ffmpeg in any way to make it work with the videos, I have just installed and did nothing else with them. I have been pulling my hair out for the past two days. Any help is appreciated.

• How to capture a layered window with transparency background properly ? (using BitBlt)

  25 octobre 2016, par Mitra M

  I want to capture a WPF window (WPF layered window) with transparency background.

  To do that I tried FFmpeg, But :

  1 - If I set AllowTransparency (this is a property of WPF window) to false ,I can capture the window by gdigrab (this is an ffmpeg device), but output has black background.(I don’t want black background)

  2 - If I set AllowTransparency to true then gdigrab won’t work. (get black frame only)

  I have read David’s nice article, he has said :

  if you use BitBlt to do this, you could “or in” the CAPTUREBLT flag if
  you wanted to capture windows that are layered

  The gdigrab uses BitBlt, this is gdigrab.c code snippet :

  /* Blit screen grab */
  
      if (!BitBlt(dest_hdc, 0, 0,
  
                  clip_rect.right - clip_rect.left,
  
                  clip_rect.bottom - clip_rect.top,
  
                  source_hdc,
  
                  clip_rect.left, clip_rect.top, SRCCOPY | CAPTUREBLT)) {
  
          WIN32_API_ERROR("Failed to capture image");
  
          return AVERROR(EIO);
  
      }

  You can see the flags . (SRCCOPY | CAPTUREBLT).

  Please tell me :

  1- Why the gdigrab can not capture a WPF window properly ?

  2 - What changes in this code should be done to do this ?

  (Sorry for my English, I used translate.google)

  Thanks