vorbis-ruby

Ruby FFI bindings for libvorbis and libvorbisenc. Provides Vorbis audio codec encoding functionality.

libvorbis and libvorbisenc must be installed on your system.

macOS:

brew install libvorbis

Debian / Ubuntu:

sudo apt-get install libvorbis-dev

Fedora / RHEL:

sudo dnf install libvorbis-devel

Add to your Gemfile:

gem "vorbis-ruby"

Or install directly:

gem install vorbis-ruby

require "vorbis"

File.open("output.ogg", "wb") do |f|
  encoder = Vorbis::Encoder.new(
    channels: 2,
    rate: 44100,
    quality: 0.4,
    comments: { "ARTIST" => "Test", "TITLE" => "Hello" }
  )

  encoder.write_headers { |data| f.write(data) }

  # PCM data as per-channel float arrays (-1.0 to 1.0)
  samples = [Array.new(1024, 0.0), Array.new(1024, 0.0)]
  encoder.encode(samples) { |data| f.write(data) }

  encoder.finish { |data| f.write(data) }
  encoder.close
end

High-level encoder that manages all Vorbis resources internally.

• initialize(channels:, rate:, quality: 0.4, comments: {}) — Create encoder with VBR quality (-0.1 to 1.0)
• write_headers { |data| } — Yield OGG header pages
• encode(samples) { |data| } — Encode PCM samples (array of per-channel float arrays) and yield OGG pages
• finish { |data| } — Signal end-of-stream and yield remaining OGG pages
• close — Release all resources

Low-level wrapper for vorbis_info.

• encode_init_vbr(channels:, rate:, quality:) — Set up VBR encoding
• encode_init(channels:, rate:, nominal_bitrate:, max_bitrate: -1, min_bitrate: -1) — Set up CBR/ABR encoding
• channels, rate, bitrate_nominal — Accessors
• clear — Release resources

Low-level wrapper for vorbis_comment.

• add_tag(tag, value) — Add a comment tag
• query(tag, index = 0) — Query a tag value
• query_count(tag) — Count tags with a given name
• vendor — Get the vendor string
• clear — Release resources

Low-level wrapper for vorbis_dsp_state.

• headerout(comment) — Generate 3 header packets
• analysis_buffer(samples) — Get per-channel write buffers
• wrote(samples) — Notify samples written (0 for EOS)
• clear — Release resources

Low-level wrapper for vorbis_block.

• blockout — Extract a block from DSP state
• analysis_and_addblock — Analyze block and add to bitrate management
• flush_packet — Flush a packet from bitrate management
• clear — Release resources

The gem is available as open source under the terms of the MIT License.