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• FFMPEG is not recording the whole window

  25 mai 2021, par John

  I'm using FFMPEG to record a window as illustrated in the figure below. In all cases, the right hand side of the recorded window is cropped. The command I'm giving is

  



  ffmpeg -f gdigrab -i title="example.txt - Notepad++" output.mkv


  



  Any suggestion on how to fix this problem is much appreciated.

  



  

  



  Here are some additional info :

  



  

  • Running Windows 10

  


  • Using ffmpeg-20181215-011c911-win64-static, but I have the same issue using other versions of FFMPEG

  


  • Desktop resolution is 3200x1800 (dpi scaling issue ?)

  


  



  This is what the recorded area looks like in the example above

  



  

  



  Update 1 :

  



  Recording the whole desktop works fine, however, when recording a region using x and y offsets, the region captured is correct, but the region indicated is wrong. I illustrate this in the image below that shows a screen capture of the desktop during recording. The background image is a grid and the taskbar has been hidden.

  



  

  



  The size of the area to capture is specified to 1280x720, but the region indicated is 1600x900. Also, the x offset is specified to 400px, but the region indicted starts at 500px.

  



  The area recorded is correct ! The image below shows a screenshot of the recording during playback in vlc, note that the "misplaced" region indicator can be seen

  



  

  



  Update 2 :

  



  I noticed that the cursor, the mouse, is not correctly placed when capturing from the desktop, see recording below. Everything looks fine during recording, but at playback the cursor is misplaced.

  



  

  



  The command issued for the recording above was :

  



  ffmpeg -f gdigrab -framerate 30 -offset_x 1820 -offset_y 100 -video_size 1280x720 -i desktop output5.mkv


  



  Windows 10 / ffmpeg-20181215-011c911-win64-static

  


• ffmpegthumbnailer error with carrierwave-video-thumbnailer

  30 janvier 2014, par scientiffic

  I am getting the error "No such file or directory" when I try to run ffmpegthumbnailer using the carrierwave-video-thumbnailer gem.

  I confirmed that ffmpegthumbnailer is working correctly on my computer since I can generate a thumbnail image from a video straight from the command line.

  From my logs, it looks like my app thinks that it has generated a thumbnail image. However, when I look in the directory, there is no file tmpfile.png, and my app fails with the error.

  Has anyone successfully used the carrierewave-video-thumbnailer gem to create thumbnails, and if so, what am I doing wrong ? Alternatively, if there is some way I can just run ffmpegthumbnailer within my model, I could do that too.

  Here are my logs :

  Running....ffmpegthumbnailer -i /Users/.../Website/public/uploads/tmp/1380315873-21590-2814/thumb_Untitled.mov -o /Users/.../Website/public/uploads/tmp/1380315873-21590-2814/tmpfile.png -c png -q 10 -s 192 -f
  
  Success!
  
  Errno::ENOENT: No such file or directory - (/Users/.../Website/public/uploads/tmp/1380315873-21590-2814/tmpfile.png, /Users/.../Website/public/uploads/tmp/1380315873-21590-2814/thumb_Untitled.mov)

  video_path_uploader.rb

  class VideoPathUploader < CarrierWave::Uploader::Base
  
    include CarrierWave::Video
  
    include CarrierWave::Video::Thumbnailer
  
  
  
    process encode_video: [:mp4]
  
  
  
    # Include RMagick or MiniMagick support:
  
    # include CarrierWave::RMagick
  
    include CarrierWave::MiniMagick
  
  
  
    # Choose what kind of storage to use for this uploader:
  
    # storage :file
  
    storage :fog
  
  
  
    # Override the directory where uploaded files will be stored.
  
    # This is a sensible default for uploaders that are meant to be mounted:
  
    def store_dir
  
      "#{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

  Video.rb

  class Video < ActiveRecord::Base
  
    # maybe we should add a title attribute to the video?
  
    attr_accessible :position, :project_id, :step_id, :image_id, :saved, :embed_url, :thumbnail_url, :video_path
  
    mount_uploader :video_path, VideoPathUploader
  
  ...
  
  end

• FFMPEG -codec copy creates incorrect duration when edit atoms are in input

  6 juin 2019, par Jesse Michael

  When using FFMPEG to -codec copy an input with Edit Atoms before transcoding, the resulting output contains incorrect durations.

  mp4dump reveals a list of edit atoms for this example mp4 on the audio track.

  ...
  
      [edts] size=8+52
  
        [elst] size=12+40
  
          entry count = 3
  
          entry/segment duration = 111968
  
          entry/media time = 0
  
          entry/media rate = 1
  
          entry/segment duration = 111968
  
          entry/media time = 322560
  
          entry/media rate = 1
  
          entry/segment duration = 111968
  
          entry/media time = 645120
  
          entry/media rate = 1
  
  ...

  using ffmpeg version 4.1.3 and running

  ffmpeg -i example.mp4 -codec copy example-copy.ts

  and then running

  ffmpeg -i example-copy.ts example-out.mp4

  produces an output with a different duration than the input introducing A/V sync issues

  input audio stream duration=21.868776

  output audio stream duration=23.821769

  The issue does not occur when skipping the -codec copy step and going straight to the transcode step (but this step is currently an important part of our workflow).

  The issue also doesn’t occur (for this example) when -codec copying to a different video container, like .nut, but in other examples (specifically ones with a single edit atom entry with > 0 media_time) changing the video container doesn’t solve the issue.

  Is FFMPEG ignoring/dropping the edit list when using the codec copy operation ?

  Is this the expected behavior or is there and issue with FFMPEG ?