ladybird/Libraries/LibWeb/WebAudio/AnalyserNode.h
Noah Bright 6c6bf322ea LibWeb/WebAudio: Define and partially implement AnalyserNode
https://webaudio.github.io/web-audio-api/#AnalyserNode

Most of the interface is naively implemented. Container types
probably need adjusted (Vector<double> is used for all the processing).
A Fourier Transform is needed, but that's waiting on either a 3rd
party library or a complex number type.

There are lots of simple miscellaneous filters that need to be applied.
It could be reasonable to implement from scratch, supposing that
it can be parallelized. It might be hard to find one library with
everything. Not my call though.

Some additional scaffolding around blocks and render quanta is
probably needed before this is developed much further, which
probably comes in at the level of the AudioNode.

Co-authored-by: Tim Ledbetter <tim.ledbetter@ladybird.org>
2025-01-17 10:11:24 +01:00

84 lines
3.2 KiB
C++

/*
* Copyright (c) 2024, Noah Bright <noah.bright.1@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibJS/Forward.h>
#include <LibWeb/Bindings/PlatformObject.h>
#include <LibWeb/WebAudio/AudioNode.h>
#include <LibWeb/WebIDL/Buffers.h>
#include <LibWeb/WebIDL/ExceptionOr.h>
namespace Web::WebAudio {
// https://webaudio.github.io/web-audio-api/#AnalyserOptions
struct AnalyserOptions : AudioNodeOptions {
unsigned long fft_size { 2048 };
double max_decibels { -30 };
double min_decibels { -100 };
double smoothing_time_constant { 0.8 };
};
// https://webaudio.github.io/web-audio-api/#AnalyserNode
class AnalyserNode : public AudioNode {
WEB_PLATFORM_OBJECT(AnalyserNode, AudioNode);
GC_DECLARE_ALLOCATOR(AnalyserNode);
public:
virtual ~AnalyserNode() override;
virtual WebIDL::UnsignedLong number_of_inputs() override { return 1; }
virtual WebIDL::UnsignedLong number_of_outputs() override { return 1; }
WebIDL::ExceptionOr<void> get_float_frequency_data(GC::Root<WebIDL::BufferSource> const& array); // Float32Array
WebIDL::ExceptionOr<void> get_byte_frequency_data(GC::Root<WebIDL::BufferSource> const& array); // Uint8Array
WebIDL::ExceptionOr<void> get_float_time_domain_data(GC::Root<WebIDL::BufferSource> const& array); // Float32Array
WebIDL::ExceptionOr<void> get_byte_time_domain_data(GC::Root<WebIDL::BufferSource> const& array); // Uint8Array
unsigned long fft_size() const { return m_fft_size; }
unsigned long frequency_bin_count() const { return m_fft_size / 2; }
double max_decibels() const { return m_max_decibels; }
double min_decibels() const { return m_min_decibels; }
double smoothing_time_constant() const { return m_smoothing_time_constant; }
WebIDL::ExceptionOr<void> set_fft_size(unsigned long);
WebIDL::ExceptionOr<void> set_max_decibels(double);
WebIDL::ExceptionOr<void> set_min_decibels(double);
WebIDL::ExceptionOr<void> set_smoothing_time_constant(double);
static WebIDL::ExceptionOr<GC::Ref<AnalyserNode>> create(JS::Realm&, GC::Ref<BaseAudioContext>, AnalyserOptions const& = {});
static WebIDL::ExceptionOr<GC::Ref<AnalyserNode>> construct_impl(JS::Realm&, GC::Ref<BaseAudioContext>, AnalyserOptions const& = {});
protected:
AnalyserNode(JS::Realm&, GC::Ref<BaseAudioContext>, AnalyserOptions const& = {});
virtual void initialize(JS::Realm&) override;
private:
unsigned long m_fft_size;
double m_max_decibels;
double m_min_decibels;
double m_smoothing_time_constant;
// https://webaudio.github.io/web-audio-api/#current-frequency-data
Vector<f32> current_frequency_data();
// https://webaudio.github.io/web-audio-api/#current-time-domain-data
Vector<f32> current_time_domain_data();
// https://webaudio.github.io/web-audio-api/#blackman-window
Vector<f32> apply_a_blackman_window(Vector<f32> const& x) const;
// https://webaudio.github.io/web-audio-api/#smoothing-over-time
Vector<f32> smoothing_over_time(Vector<f32> const& current_block);
// https://webaudio.github.io/web-audio-api/#previous-block
Vector<f32> m_previous_block;
// https://webaudio.github.io/web-audio-api/#conversion-to-db
Vector<f32> conversion_to_dB(Vector<f32> const& X_hat) const;
};
}