Question

I’m using Paperclip for processing a user uploaded video with ffmpeg. I want to create a thumbnail image as well as convert the video to a standard format of my choosing. I have the ffmpeg processing working, however, I can’t seem to figure out how to update the record after it has finished processing. I’ve used a number of rails – paperclip – ffmpeg references but haven’t seen anyone converting the video and then using the converted video in the rails db, since it’s creating a new video I will need to be able to update the record from within the paperclip processor, but how to do it??

Thanks

• using Rails 3
• using paperclip processor with ffmpeg

Answer 1

Per the documentation for Paperclip::Processor:

There is only one method you must implement to properly be a subclass [of
Paperclip::Processor]: #make…

All #make needs to return is an instance of File (Tempfile is acceptable)
which contains the results of the processing.

So your Processor would look something like this:

module Paperclip
  class MyProcessor
    # ...

    def make file, options = {}, attachment = nil
      in_filename = File.absolute_path file.path  # probably just a good idea

      out_filename = 'output_filename.mp4' # doesn't matter, maybe you use
                                           # Tempfile--just need to know
                                           # the path of ffmpeg's output file
      # run ffmpeg
      self.class.run 'ffmpeg',
        "-i #{in_filename}", /* more params..., */ out_filename

      File.open out_filename, 'r'  # then just return a File object pointing to
    end                            # the output file; Paperclip does the rest
  end
end