instagram_video_codec_validation.rb

class VideoAttachment < Attachment
  validate :file_codec_validation, if: :new_record?

  # Checks video file Codec format for Instagram
  # Fails if not HEVC or H264
  # @see https://developers.facebook.com/docs/instagram-api/reference/ig-user/media#video-specifications
  # @see https://github.com/ruby-av/av/blob/master/lib/av/commands/base.rb
  def file_codec_validation
    ffmpeg = `if command -v ffmpeg 2>/dev/null; then echo "true"; else echo "false"; fi`
    av_probe = `if command -v avprobe 2>/dev/null; then echo "true"; else echo "false"; fi`

    command = if ffmpeg =~ /true/
                'ffmpeg'
              elsif av_probe =~ /true/
                'avconv'
              end

    return if command.nil?
    return if ::Av.run(%(#{command} -i "#{File.expand_path(file.queued_for_write[:original].path)}" 2>&1), [0, 1])
                  .force_encoding('UTF-8').encode('UTF-8', invalid: :replace)
                  .split("\n").detect { |line| line =~ /Video:(.*)/ }.match(/hevc|h264/)

    errors.add(:file, 'video codec is not allowed. Must be HEVC or H264')
  end
end