philomena/lib/philomena/analyzers/webm.ex

defmodule Philomena.Analyzers.Webm do
  def analyze(file) do
    %{
      extension: "webm",
      mime_type: "video/webm",
      animated?: true,
      duration: duration(file),
      dimensions: dimensions(file)
    }
  end

  defp duration(file) do
    with {output, 0} <-
           System.cmd("ffprobe", [
             "-i",
             file,
             "-show_entries",
             "format=duration",
             "-v",
             "quiet",
             "-of",
             "csv=p=0"
           ]),
         {duration, _} <- Float.parse(output) do
      duration
    else
      _ ->
        0.0
    end
  end

  defp dimensions(file) do
    System.cmd("ffprobe", [
      "-i",
      file,
      "-show_entries",
      "stream=width,height",
      "-v",
      "quiet",
      "-of",
      "csv=p=0"
    ])
    |> case do
      {output, 0} ->
        [width, height] =
          output
          |> String.trim()
          |> String.split(",")
          |> Enum.map(&String.to_integer/1)

        {width, height}

      _error ->
        {0, 0}
    end
  end
end