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• Load processed video instead of original video - Rails, Dragonfly

  1er février 2016, par Michael B

  In my Rails 4-Project, I am using Dragonfly to upload images and videos.
  For image-processing I use imagemagick, for videoprocessing I use ffmpeg.

  Videos are uploaded and stored in the folder uploads/videos. After processing, they are stored in public/ffmpeg_videos/

  My question is : How can I use the processed-video instead of the uploaded video ?

  e.g. I use this code in the view, to display a video :

  <video src="&lt;%=@video.video.url%>"></video>

  This successfully loads the original video from the upload-path. But what do I have to change, to load the video from the ffmpeg-path ?

  initializers/dragonfly.rb

  require 'dragonfly'
  
  
  
  # Configure
  
  Dragonfly.app(:images).configure do
  
    plugin :imagemagick
  
    protect_from_dos_attacks false
  
    secret 'd045734b043b4383a246c5c8daf2d3e31217dc8b030f21861e4fd16c4b72d382'
  
    url_format '/media/:job/:name'
  
  
  
    datastore :file,
  
              root_path: Rails.root.join('uploads/images/'),
  
              server_root: Rails.root.join('uploads')
  
  end
  
  
  
  Dragonfly.app(:videos).configure do
  
    secret 'd045734b043b4383a246c5c8daf2d3e31217dc8b030f21861e4fd16c4b72d382'
  
    url_format "/video/:job/:name"
  
  
  
    datastore :file,
  
              root_path: Rails.root.join('uploads/videos/'),
  
              server_root: Rails.root.join('uploads')
  
  end
  
  
  
  # Logger
  
  Dragonfly.logger = Rails.logger
  
  
  
  # Mount as middleware
  
  Rails.application.middleware.use Dragonfly::Middleware, :images
  
  Rails.application.middleware.use Dragonfly::Middleware, :videos
  
  
  
  # Add model functionality
  
  if defined?(ActiveRecord::Base)
  
    ActiveRecord::Base.extend Dragonfly::Model
  
    ActiveRecord::Base.extend Dragonfly::Model::Validations
  
  end

• Create thumbnails of sections of a torrent stream

  14 juillet 2015, par Ortixx

  I’m trying to create a little application in nodejs using the torrent-stream library to create thumbnails of a video without actually having to download the entire file. I was thinking of downloading only 10 parts, out of which I would extract an image, but then the encoding comes into play : without an I-frame I cannot extract an image out of the stream, and there is no way of me knowing where the I-frame is.

  So any ideas on how to do this ? Basically I was hoping to create 10 tiny files which I could then open in ffmpeg in order to save a thumbnail (this would give me 10 thumbnails which is want I want). I’m just not sure how to handle the stream.

• Ffmpeg encoding a video with time_base Not equal to framerate does not work hardware accelerated Video Player

  10 janvier 2020, par Gilgamesh22

  I have a time_base of 90000 with a frame rate of 30. I can generate a h264 video and have it work in VLC but this video does not work in a hardware accelerated web chrome player using Intel HD Graphics 530. If I change the time_base to 30 It works fine.

  Note : I am changing the frame->pts appropriately to match the time_base.
  Note : Video does not have audio stream

  //header.h
  
  AVCodecContext *cctx;
  
  AVStream* stream;

  Here is the non working example code

  //source.cpp
  
  stream->time_base = { 1, 90000 };
  
  stream->r_frame_rate = { fps, 1 };
  
  stream->avg_frame_rate = { fps, 1 };
  
  
  
  cctx->codec_id = codecId;
  
  cctx->time_base = { 1 ,  90000 };
  
  cctx->framerate = { fps, 1 };
  
  
  
  // ...... 
  
  // add frame code later on timestamp are in millisecond
  
  frame->pts = (timestamp - startTimeStamp)* 90;

  Here is the working example code

  //source.cpp
  
  stream->time_base = { 1, fps};
  
  stream->r_frame_rate = { fps, 1 };
  
  stream->avg_frame_rate = { fps, 1 };
  
  
  
  cctx->codec_id = codecId;
  
  cctx->time_base = { 1 ,  fps};
  
  cctx->framerate = { fps, 1 };
  
  
  
  // ...... 
  
  //  add frame code timestamp are in millisecond
  
  frame->pts = (timestamp - startTimeStamp)/(1000/fps);

  Any ideas on why the second example works and the first does not in the video player.