Behaviour for video processing adapters.

PhxMediaLibrary uses video processors to extract metadata (duration, codec, fps, dimensions) and generate poster frames from video files.

Built-in Adapters

• PhxMediaLibrary.VideoProcessor.FFmpeg — uses ffprobe and ffmpeg system executables. Selected automatically when both are on $PATH.
• PhxMediaLibrary.VideoProcessor.Null — no-op fallback used when FFmpeg is not installed. Metadata extraction and poster generation return error tuples; uploads still succeed without metadata or poster frames.

Auto-detection

No configuration is needed in the common case. The library checks for ffprobe and ffmpeg on $PATH at startup and selects the appropriate adapter automatically via PhxMediaLibrary.Config.video_processor/0.

Custom Adapters

Implement this behaviour and set in config:

defmodule MyApp.VideoProcessor do
  @behaviour PhxMediaLibrary.VideoProcessor

  @impl true
  def available?, do: true

  @impl true
  def extract_metadata(file_path) do
    {:ok, %{"duration" => 10.5, "codec" => "h264", "fps" => 30.0}}
  end

  @impl true
  def extract_poster(file_path, offset_seconds) do
    {:ok, jpeg_binary}
  end
end

config :phx_media_library,
  video_processor: MyApp.VideoProcessor