Ruby binding

bindings/ruby/.gitignore

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+/.bundle/
+/.yardoc
+/_yardoc/
+/coverage/
+/doc/
+/pkg/
+/html/
+/spec/reports/
+/tmp/
+*.bundle
+*.so
+*.o
+*.a
+mkmf.log
+target/
+Gemfile.lock
+/vendor/bundle/
+ext/ebur128_stream/.rustc_info.json
+ext/ebur128_stream/release/

bindings/ruby/CHANGELOG.md

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+## [Unreleased]
+
+## [0.1.0] - 2026-08-11
+
+- Initial release

bindings/ruby/Gemfile

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+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+# Specify your gem's dependencies in ebur128_stream.gemspec
+gemspec

bindings/ruby/README.md

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+# EBUR128Stream
+
+A Ruby binding for [ebur128-stream][rust-impl], a streaming, zero-allocation EBU R128 loudness measurement in pure Rust.
+
+## Installation
+
+Install the gem and add to the application's Gemfile by executing:
+
+```bash
+bundle add ebur128_stream
+```
+
+If bundler is not being used to manage dependencies, install the gem by executing:
+
+```bash
+gem install ebur128_stream
+```
+
+## Usage
+
+```ruby
+require "ebur128_stream"
+
+include EBUR128Stream
+
+analyzer = Analyzer.new(
+  channels: [:left, :right],
+  sample_rate: 48_000,
+  modes: [:integrated, :true_peak]
+)
+analyzer.push_interleaved samples
+
+report = analyzer.finalize
+report.integrated_lufs # => -8.030723453035735
+report.true_peak_dbtp  # => 20.01377283514713
+```
+
+EBUR128Stream provides two main classes:
+
+* [Analyzer](#analyzer) analyzes audio data and reports loudness.
+* [Normalizer](#normalizer) analyzes audio data and applies the calibrated gain.
+
+<a name="analyzer"></a>
+### Analyzer
+
+EBUR128Stream::Analyzer is a streaming EBU R128 loudness analyzer. It reads audio data and reports statistics such as integrated LUFS, dBTP.
+
+It provides a streaming API, which means you can push chunks of audio data incrementally and get the current status (EBUR128Stream::Snapshot) and the final report (EBUR128Stream::Report).
+
+### Initialization
+
+First, initialize EBUR128Stream::Analyzer:
+
+```ruby
+analyzer = EBUR128Stream::Analyzer.new(
+  # Required. Supports :left, :right, :center, :left_surround, :right_surround, :lfe, :other.
+  channels: [:left, :right],
+
+  # Optional. Must be one of 22_050, 32_000, 44_100, 48_000, 88_200, 96_000, 192_000. Defaults to 48_000.
+  sample_rate: 48_000,
+
+  # Optional. Supports :integrated, :momentary, :short_term, :true_peak, :lra, :all. Defaults to [:all].
+  modes: [:all],
+
+  # Optional. Hint at audio length in seconds so that buffer is allocated first.
+  expected_duration: 60
+)
+```
+
+See [Rust documentation](https://docs.rs/ebur128-stream/latest/ebur128_stream/struct.AnalyzerBuilder.html) for details on arguments.
+
+### Pushing samples
+
+Then, push audio samples to EBUR128Stream::Analyzer#push_interleaved or EBUR128Stream::Analyzer#push_planar as you get them:
+
+```ruby
+while samples = get_samples
+  analyzer.push_interleaved(samples)
+  # Or, analyzer.push_planar samples
+end
+```
+
+Interleaved samples looks like this:
+
+```ruby
+[L1, R1, L2, R2, L3, R3, ...]
+```
+
+(*Note* that it's not a 2-D array (`[[L1, R1], [L2, R2], ...]`) but a flat array.)
+
+Planar samples looks like this:
+
+```ruby
+[[L1, L2, L3, ...], [R1, R2, R3, ...]]
+```
+
+In addition to 1-D or 2-D `Array`s, EBUR128Stream::Analyzer#push_interleaved and EBUR128Stream::Analyzer#push_planar accept MemoryView producers such as:
+
+* `Gst::Sample` from [GStreamer][] gem
+* `Torch::Tensor` from [TorchAudio][] or [TorchCodec][] gem (w/ [NDAV::TorchTensor][])
+* `Numo::NArray` from [Numo::NArray][] or [Numo::NArray Alternative][] gem when generating and processing audio data with it (w/ [NDAV::Numo::NArray][])
+
+TorchAudio example here:
+
+```ruby
+samples, sample_rate = TorchAudio.load("path/to/audio")
+analyzer.push_planar(samples)
+```
+
+### Snapshots
+
+At any point during streaming, you can get the current statistics (EBUR128Stream::Snapshot) by calling EBUR128Stream::Analyzer#snapshot:
+
+```ruby
+snapshot = analyzer.snapshot
+
+snapshot.programme_duration_seconds #=> Current duration
+snapshot.momentary_lufs             #=> Loudness sliding 400ms window in LUFS
+snapshot.short_term_lufs            #=> Loudness sliding 3s window in LUFS
+snapshot.integrated_lufs            #=> Loudness so far in LUFS
+snapshot.true_peak_dbtp             #=> True peak so far in dBTP
+snapshot.loudness_range_lu          #=> Loudness range in LU
+```
+
+The attributes may be `nil` when there are not enough samples or when the corresponding mode was not specified at initialization.
+
+EBUR128Stream::Snapshot implements `#to_h`:
+
+```ruby
+snapshot.to_h #=> {momentary_lufs: ..., short_term_lufs: ..., ...}
+```
+
+Also, `#deconstruct_keys` is implemented:
+
+```ruby
+snapshot.deconstruct_keys(nil) #=> {momentary_lufs: ..., short_term_lufs: ..., ...}
+
+case analyzer.snapshot
+in EBUR128Stream::Snapshot[true_peak_dbtp: 1.0..] => snapshot
+  $stderr.puts "High true peak found at #{snapshot.programme_duration_seconds}s: #{snapshot.true_peak_dbtp} dBTP"
+else
+  # noop
+end
+```
+
+### Finalization
+
+Finally, call EBUR128Stream::Analyzer#finalize to complete the analysis and get the report:
+
+```ruby
+report = analyzer.finalize
+
+report.programme_duration_seconds #=> Total duration in seconds
+report.integrated_lufs
+report.loudness_range_lu
+report.true_peak_dbtp
+report.momentary_max_lufs  #=> Maximum momentary loudness in LUFS
+report.short_term_max_lufs #=> Maximum short term loudness in LUFS
+```
+
+EBUR128Stream::Report also implements `#to_h` and `#deconstruct_keys` like EBUR128Stream::Snapshot.
+
+<a name="normalizer"></a>
+### Normalizer
+
+EBUR128Stream::Normalizer analyzes audio data and normalizes it to the target loudness in place.
+
+#### Initialization
+
+Initialize EBUR128Stream::Normalizer with target loudness.
+
+```ruby
+normalizer = EBUR128Stream::Normalizer.new(
+  # Required.
+  sample_rate: 48_000,
+
+  # Required.
+  channels: [:left, :right],
+
+  # Optional. Target loudness in LUFS. Defaults to -23.0.
+  target_lufs: -14.0,
+
+  # Optional. Cap the post-normalisation true peak at this dBTP value.
+  true_peak_ceiling_dbtp: -1.0,
+)
+```
+
+#### Normalization
+
+Pass interleaved samples to EBUR128Stream::Normalizer#normalize_in_place:
+
+```ruby
+report = normalizer.normalize_in_place(interleaved_samples)
+```
+
+*Note* that it modifies the passed `Array` in place as the method name implies.
+
+This returns EBUR128Stream::NormalizeReport:
+
+```ruby
+report.measured_integrated_lufs #=> Measured integrated loudness before normalization.
+report.measured_true_peak_dbtp  # Measured true peak before normalization, in dBTP.
+report.target_lufs              #=> Target loudness, in LUFS.
+report.true_peak_ceiling_dbtp   #=> True peak ceiling in dBTP.
+report.applied_gain_db          #=> Gain that was actually applied in dB.
+report.limited_by_true_peak     #=> true if the gain was attenuated to honour the true peak ceiling.
+```
+
+EBUR128Stream::NormalizeReport also implements `#to_h` and `deconstruct_keys`.
+
+Additionally, it accepts MemoryView as a `samples` argument. The MemoryView must be writable.
+
+## Examples
+
+Complete examples are available in the sample directory.
+
+* sample/analyze-wavefile.rb - A basic example of analyzing audio from wave file using pure-Ruby [WaveFile][] gem.
+* sample/analyze-microphone.rb - An example that displays microphone loudness in real time.
+* sample/analyze-planar-data.rb - An example of analyzing planar audio data instead of interleaved data.
+* sample/normalize.rb - An example of normalizing audio data to desired loudness and saving it to a file.
+
+## Development
+
+After checking out the repo, run `bundle install` to install dependencies. Then, run `bundle exec rake test` to run the tests. You can also run `bundle exec rake console` for an interactive prompt that will allow you to experiment.
+
+To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and the created tag, and push the `.gem` file to [rubygems.org](https://rubygems.org).
+
+## Contributing
+
+Bug reports and pull requests are welcome on GitHub at https://github.com/vanjamodrinjak21/ebur128_stream. Mention @KitaitiMakoto for issues and pull requests related to the Ruby binding.
+
+## License
+
+Licensed under either of
+
+- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+- MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+## See also
+
+* [Rust crate][rust-impl]
+* [BS.1770][]
+
+[rust-impl]: https://github.com/vanjamodrinjak21/ebur128-stream
+[Analyzer]: rdoc-ref:EBUR128Stream::Analyzer
+[BS.1770]: https://www.itu.int/rec/R-REC-BS.1770
+[GStreamer]: https://github.com/ruby-gnome/ruby-gnome/tree/main/gstreamer
+[TorchAudio]: https://github.com/ankane/torchaudio-ruby
+[TorchCodec]: https://github.com/ankane/torchcodec-ruby
+[Numo::NArray]: https://ruby-numo.github.io/numo-narray/
+[Numo::NArray Alternative]: https://github.com/yoshoku/numo-narray-alt
+[WaveFile]: https://wavefilegem.com/
+[NDAV::TorchTensor]: https://gitlab.com/KitaitiMakoto/ndav-torch-tensor
+[NDAV::Numo::NArray]: https://gitlab.com/KitaitiMakoto/ndav-numo-narray

bindings/ruby/Rakefile

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+# frozen_string_literal: true
+
+require "rubygems/tasks"
+require "rake/testtask"
+require "kar/dsl"
+require "rdoc/task"
+
+GEMSPEC = Gem::Specification.load("ebur128_stream.gemspec")
+
+LICENSE_FILES = FileList["LICENSE-APACHE", "LICENSE-MIT"]
+LICENSE_FILES.each do |license|
+  file license => "../../#{license}" do |t|
+    copy t.source, t.name
+  end
+end
+
+Gem::Tasks.new
+
+cargo "ebur128_stream"
+
+Rake::TestTask.new(test: :cargo)
+RDoc::Task.new
+
+task default: :test
+
+task sync_version: ["lib/ebur128_stream/version.rb", "ext/ebur128_stream/Cargo.toml"] do |t|
+  require_relative t.sources[0]
+  sh "cargo", "set-version", "--manifest-path", t.sources[1], "--offline", EBUR128Stream::VERSION
+end
+
+task build: [:sync_version, :cargo] + LICENSE_FILES

bindings/ruby/ebur128_stream.gemspec

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+# frozen_string_literal: true
+
+require_relative "lib/ebur128_stream/version"
+
+Gem::Specification.new do |spec|
+  spec.name = "ebur128_stream"
+  spec.version = EBUR128Stream::VERSION
+  spec.authors = ["Kitaiti Makoto"]
+  spec.email = ["KitaitiMakoto@gmail.com"]
+  spec.licenses = ["Apache-2.0", "MIT"]
+
+  spec.summary = "Streaming, zero-allocation EBU R128 loudness measurement."
+  spec.description = "Ruby binding for Streaming, zero-allocation EBU R128 loudness measurement in pure Rust."
+  spec.homepage = "https://github.com/vanjamodrinjak21/ebur128-stream"
+  spec.required_ruby_version = ">= 3.2.0"
+  spec.metadata["allowed_push_host"] = "https://rubygems.org"
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = "https://github.com/KitaitiMakoto/ebur128-stream/tree/main/bindings/ruby"
+  spec.metadata["changelog_uri"] = "https://github.com/KitaitiMakoto/ebur128-stream/tree/main/bindings/ruby/CHANGELOG.md"
+
+  # Uncomment the line below to require MFA for gem pushes.
+  # This helps protect your gem from supply chain attacks by ensuring
+  # no one can publish a new version without multi-factor authentication.
+  # See: https://guides.rubygems.org/mfa-requirement-opt-in/
+  # spec.metadata["rubygems_mfa_required"] = "true"
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  gemspec = File.basename(__FILE__)
+  spec.files = IO.popen(%w[git ls-files -z], chdir: __dir__, err: IO::NULL) do |ls|
+    ls.readlines("\x0", chomp: true)
+  end + ["LICENSE-APACHE", "LICENSE-MIT"]
+  spec.executables = spec.files.grep(%r{\Abin/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+  spec.extensions = ["ext/ebur128_stream/Cargo.toml"]
+
+  # Uncomment to register a new dependency of your gem
+  # spec.add_dependency "example-gem", "~> 1.0"
+
+  spec.add_development_dependency "irb"
+  spec.add_development_dependency "rake"
+  spec.add_development_dependency "test-unit"
+  spec.add_development_dependency "rubygems-tasks"
+  spec.add_development_dependency "kar"
+  spec.add_development_dependency "numo-narray-alt"
+  spec.add_development_dependency "ndav-numo-narray"
+
+  # For more information and examples about making a new gem, check out our
+  # guide at: https://guides.rubygems.org/make-your-own-gem/
+end