yamdi

Yamdi is a ruby wrapper around the command line tool yamdi (github.com/ioppermann/yamdi). You’ll need yamdi installed in order for the gem to be of any use. If you are on OSX I recommend using homebrew (brew install yamdi).

The Yamdi command line tool expects to receive a path to an flv file and will return XML file of the extracted metadata that we then wrap in a ruby object and use to expose the metadata.

The current gem version only supports the reading of metadata. The command line tool also supports the writing of the metadata into a new .flv file but this is not yet supported in this gem.

Tested under ruby 1.8.7 and 1.9.2

Usage

@metadata = Yamdi.new('path/to/file.flv')

@metadata.duration #=> 6.02

@metadata.key_frames.each do |key_frame|
  key_frame.time     #=> 5.87
  key_frame.location #=> 13467
end

Paperclip Processor

You can also use Yamdi in a Paperclip processor. I’ve provided a simple example in lib/paperclip_processors/metadata_extractor.rb

This is useful for adding things like video duration to your db when a user uploads a video.

class Video
  has_attached_file :video,
                    :styles => {:orginal => {}},
                    :processors => [:metadata_extractor]
end

Be sure you add the styles hash even if it is empty as above or your paperclip processors won’t run.

Refreshing Exisitng Videos

Perhaps you’re adding yamdi to your current set up, want to refresh the data in your models or add a new column to present to your users.

This is easily accomplished of you are using Paperclip. I’ve added an example rake task in lib/tasks/metadata_refresh.rake

Supported methods

duration: float, in seconds
has_keyframes?: boolean
has_video?: boolean
has_audio?: boolean
has_metadata?: boolean
has_cue_points?: boolean
can_seek_to_end?: boolean
audio_codec_id: integer
audio_sample_rate: integer
audio_data_rate: integer
audio_sample_size: integer
audio_delay: float, in seconds
stereo?: boolean
video_codec_id: integer
frame_rate: float, in seconds
video_data_rate: integer
height: integer
width: integer
data_size: integer
audio_size: integer
video_size: integer
file_size: integer
last_timestamp: float, in seconds
last_video_frame_timestamp: float, in seconds
last_key_frame_timestamp: float, in seconds
last_key_frame_location: integer
key_frames: Array of key frame data, each item contains the following

time

float, in seconds
location

integer

Contributing to yamdi