instagram_video_codec_validation.rb

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