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• Rails Thumbnails for videos being uploaded to S3

  20 octobre 2015, par Dani

  I have a rails application where I need to upload videos to an amazon s3 bucket alongwith their thumbnails. I am using ffmpeg to generate thumbnails and I am using carrierwave to handle video uploads. Here is my video uploader class

   class VideoUploader < CarrierWave::Uploader::Base
  
    include CarrierWave::Video
  
    storage :fog
  
    def store_dir
  
       "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  
    end
  
    def extension_white_list
  
      %w(mp4 flv)
  
    end
  
  end

  The video uploads fine and the column for video url is set in videos table but I want to generate thumbnail and upload it as well. I know I have to use ffmpeg here but don’t exactly know how to do it.

  Any help will be appreciated.

• How to concat multiple sets of 2 videos using ffmpeg and for loop

  25 janvier 2020, par Rawr Linux Mmm

  I am trying to batch merge multiple sets of 2 videos.
  Clarification : I am trying to merge 2 videos into 1, multiple times, quickly.

  I have two folders, one full of mp4’s in which I want in the beginning of the output video. Another full of mp4’s in which I want at the end of the output video.

  Basically I am trying to merge the first video in folder1 with the first video in folder2, and then the second video in folder1 with the second video in folder2, etc...

  Here is what I have, and I was trying to run this script inside the video directory of folder1.

  for filename in *.mp4; do
  
      vids2="/path/to/2nd/set/of/videos/${filename%.*}"
  
      out="/path/to/output/folder/$(date +'%Y-%m-%d_%H:%M:%S').mp4"
  
      ffmpeg -i "${vids2}.mp4" -i "${filename%.*}.mp4" -acodec copy -vcodec copy "$out"
  
  done

  I also tried this in which I ran from anywhere since I defined all the paths.

  for filename in *.mp4; do
  
      vid1="/path/to/folder1/videos/${filename%.mp4}"
  
      vid2="/path/to/folder2/videos/${filename%.mp4}"
  
      out1="/output/folder/$(date +'%Y-%m-%d_%H:%M:%S').mp4"
  
      ffmpeg -i "$vid1" -i "$vid2" -acodec copy -vcodec copy "$out1"
  
  done

  but that didn’t work either...

  Does anyone know what I am doing wrong ?

• Displaying multiple videos on Panels locks UI - using Refresh() / Invalidate()

  7 mai 2015, par eruslu

  I try to show 32 different videos ( 768 * 532 pixels and 25 fps) on an application as two 4x4 displays. Each video is displayed on a Player class which has a Panel object.
  I get the RTP streams from network and converting them to bitmap image using FFmpeg and set bitmaps as panel background images and then Refresh() the panel.
  When the number of displaying videos increases (as 17-18) the UI starts to lock, it is not responding.
  Then I use Invalidate(), this time UI is not locking, it responds any events even for 32 displays but after 17-18 display it can not catch up refreshing rate (25fps). The videos are displayed by skipping some of the frames.
  I am setting background images of Panel’s and refreshing them in different threads. Do I need to do one refreshing for all panels. Or use another refreshing method ?
  Any help will be appreciated, thank you.