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• Using ffmpeg to create video from images - Python [duplicate]

  24 mars 2017, par Harel

  This question already has an answer here :

  • Communicate multiple times with a process without breaking the pipe ?
    
    4 answers
    

  I’m using FFMPEG in python (using this tutorial) and my main goal is to take a screenshot and append it into an existing mp4 video(append it using the encoder, not raw appending).

  That’s the code I’m using right now, this script only writes a video of one frame(the first screenshot) and doesn’t do anything with all the other screenshots.

  command = [ FFMPEG_BIN,
  
      '-f', 'rawvideo',
  
      '-codec', 'rawvideo',
  
      '-s', '1920x1080', # size of one frame
  
      '-pix_fmt', 'rgb24',
  
      '-r', '24', # frames per second
  
      '-i', '-', # The input comes from a pipe
  
      '-an', # Tells FFMPEG not to expect any audio
  
      '-vcodec', 'mpeg4',
  
      'my_output_videofile.mp4' ]
  
  
  
  for x in range(30):
  
      pipe = sp.Popen(command, stdin = sp.PIPE, stderr = sp.PIPE)
  
      im = np.array(ImageGrab.grab()).tostring()
  
      pipe.communicate(input = im)
  
      pipe.stdin.close()
  
      if pipe.stderr is not None:
  
          pipe.stderr.close()
  
      pipe.wait()

  Edit :
  Apparently using Popen.communicate breaks the pipe (Thanks to Peter Wood !).

  After fixing the pipe breaking scenario I have encountered another problem, after writing 235 frames to the video the program crashes.

  The new edited script :

  command = [ FFMPEG_BIN,
  
      '-y',
  
      '-f', 'rawvideo',
  
      '-codec', 'rawvideo',
  
      '-s', '1920x1080', # size of one frame
  
      '-pix_fmt', 'rgb24',
  
      '-r', '24', # frames per second
  
      '-i', '-', # The input comes from a pipe
  
      '-an', # Tells FFMPEG not to expect any audio
  
      '-vcodec', 'mpeg4',
  
      'my_output_videofile.mp4' ]
  
  
  
  pipe = sp.Popen(command, stdin = sp.PIPE, stderr = sp.PIPE)
  
  
  
  for x in range(300):
  
      print x
  
  
  
      im = np.array(ImageGrab.grab()).tostring()
  
      pipe.stdin.write(im)
  
      pipe.stdin.flush()

• Permission denied when trying to call ffmpeg on heroku

  1er décembre 2013, par chuck w

  I have a rails 3.1 web app on Heroku (cedar) that that allows users to post stories with photo and video attachments using the paperclip gem (3.5.1). Uploads are stored on s3. This has been working 100% for many months.

  I have recently added video transcoding and thumbnailing to my dev machine with the paperclip-ffmpeg gem (1.0.1) and ffmpeg running locally. This is also working.

  I've followed these instructions to build and install ffmpeg on heroku, and I've altered my Heroku app's path so that it reads as follows :

  PATH:   bin:vendor/ffmpeg/bin:vendor/bundle/ruby/1.9.1/bin:/usr/local/bin:/usr/bin:/bin

  and my app's LD_LIBRARY_PATH so that it reads as follows :

  LD_LIBRARY_PATH:             vendor/ffmpeg/lib:/usr/local/lib

  Finally, I've vendored ffmpeg into my app with the following structure :

  

  When I commit and push these changes to Heroku and POST a story that has a video I get the following output on Heroku logs :

  2013-11-30T22:51:46.711010+00:00 app[web.1]: Started POST "/stories" for 71.80.218.93 at        
  
  2013-11-30 22:51:46 +0000
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: Cocaine::ExitStatusError (Command 'ffprobe 
  
  "/tmp/sideways video20131130-2-14w1q4j.mp4" 2>&1' returned 126. Expected 0
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: Here is the command output:
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: 
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]:   app/controllers/stories_controller.rb:11:in     
  
  `create'
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: 
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: 
  
  2013-11-30T22:51:47.019228+00:00 heroku[router]: at=info method=POST path=/stories     
  
  host=myapp.herokuapp.com fwd="71.80.218.93" dyno=web.1 connect=1ms    
  
  service=3130ms status=500 bytes=754
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: 
  
  2013-11-30T22:51:47.023600+00:00 app[web.1]: cache: [POST /stories] invalidate, pass
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: sh: ffprobe: Permission denied
  
  2013-11-30T22:51:47.023119+00:00 app[web.1]: ):

  Also, running the console command : heroku run "ffmpeg -version" -a myapp
  returns :

  Running ffmpeg -version attached to terminal... up, run.6591
  
  bash: vendor/ffmpeg/bin/ffmpeg: Permission denied

  Here is my Post model paperclip set-up :

  class Post < ActiveRecord::Base
  
  
  
    attr_accessible :contents, :photo, :video
  
  
  
    belongs_to    :story, :touch => true
  
    belongs_to    :user, :touch => true
  
  
  
    has_attached_file :photo, 
  
                      :styles => { 
  
                        :thumb => ["100x140>", :jpg],
  
                        :medium => ["400x400>", :jpg],
  
                        :large => ["800x800>", :jpg]
  
                      },
  
                      :processors => [:thumbnail],
  
                      :storage => :s3,
  
                      :s3_credentials => "#{Rails.root.to_s}/config/s3.yml",
  
                      :path => "/:style/:id/:filename"
  
  
  
    has_attached_file :video, 
  
                      :storage => :s3,
  
                      :s3_credentials => "#{Rails.root.to_s}/config/s3.yml",
  
                      :path => "/video/:id/:filename",
  
                      :styles => {
  
                        :thumb => { :geometry => "140x100#", :format => 'jpg', :time => 10 },
  
                        :medium => { :geometry => "480x360", :format => 'mp4' },
  
                      }, :processors => [:ffmpeg]

  Why am I getting these "permission denieds" ? Any help would be greatly appreciated !!!

• Android MediaExtractor crash when decoding some mp4 files. Libc fatal signal 11

  23 octobre 2015, par wonglik

  I am using Google Grafika examples to display video on TextureView. "Double decode" to be more specific . Code work most of the time but for some mp4 files it crash giving only :

  libc: Fatal signal 11 (SIGSEGV), code 1, fault addr 0x0 in tid 7998

  Same code works for webM files and most mp4 files. Place where I expect it to fail is :

  extractor = new MediaExtractor();
  
  extractor.setDataSource(sourceFile);

  in MoviePlayer [L:113]

  Any hint how to walk around or what might be the problem ?