rawler / elixir-subtitles

Convert subtitles between different formats

Subtitles

This library provides several tools for manipulating and converting subtitles

Installation

If available in Hex, the package can be installed by adding subtitles to your list of dependencies in mix.exs:

def deps do
  [
    {:subtitles, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/subtitles.

Usage

This library only supports subtitles in UTF-8 format.

All functions convert all line endings to LF before operations are done.

Tests

Run tests:

$ mix espec

Functions

Subtitles

Subtitles.get_format(subtitle)

Returns the subtitle format as an atom, defaults to :unknown

subtitle = "WEBVTT\n\n..."
Subtitles.get_format(subtitle) # :vtt

subtitle = "1\r\n..."
Subtitles.get_format(subtitle) # :srt

subtitle = "Anything else"
Subtitles.get_format(subtitle) # :unknown

Subtitles.parse(subtitle)

Tries to figure out the format of the subtitle and then parse it
by using the correct parser, returning a tuple:

subtitle = "WEBVTT\n\n..."
Subtitles.parse(subtitle) # {:ok, result}

subtitle = "Anything else"
Subtitles.parse(subtitle) # {:error, "Unknown subtitle format"}

Subtitles.parse(subtitle, type)

Dispatches the subtitle to the parser of type type and returns a tuple (see above):

Subtitles.parse(sub, :vtt) == Subtitles.VttParser.parse(sub)
Subtitles.parse(sub, :srt) == Subtitles.SrtParser.parse(sub)

Subtitles.SrtParser/Subtitles.VttParser

Subtitles.SrtParser.parse(subtitle) Subtitles.VttParser.parse(subtitle)

Returns a parsed list of all cues in the subtitle in the following format:

%Subtitle{
  from: ~T[00:00:00.000], # cue from, Elixir Time
  to: ~T[00:00:12.345],   # cue to, Elixir time
  parts: [
    %SubtitlePart{          # Cue data, one per line
      text_data: "Cue text" # actual text of the cue
    }
  ]
}

Subtitles.SrtFormatter

Subtitles.SrtFormatter.format(subtitles)

Takes a list of Subtitle structs and returns an srt string

Subtitles.VttFormatter

Subtitles.SrtFormatter.format(subtitles)

Takes a list of Subtitle structs and returns a vtt string

Notes

The current format detectors are quite dumb and will only match as follows:

vtt -> starts with WEBVTT

srt -> starts with a full cue