apm

package module
v0.1.4 Latest Latest
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 Go to latest Published: Feb 4, 2026 License: BSD-3-Clause Imports: 5 Imported by: 0

README

Go WebRTC Audio Processing Module (APM)

Go bindings for WebRTC's AudioProcessing module, providing production-quality audio processing for voice applications. Built on the extensively tested and optimized WebRTC audio engine, this library is ideal for real-time voice communication scenarios.

✨ Key Features

🎯 Audio Processing Capabilities
  • Echo Cancellation (AEC) - Effectively removes speaker audio that leaks into the microphone
  • Noise Suppression (NS) - Significantly reduces background noise while preserving speech clarity
  • Automatic Gain Control (AGC) - Intelligently normalizes audio levels automatically
  • High-Pass Filter (HPF) - Removes DC offset and low-frequency noise
🚀 Performance Advantages
  • ✅ Powered by industry-leading WebRTC audio processing engine
  • ✅ Optimized specifically for real-time voice applications
  • ✅ Low-latency, high-performance processing

📦 Installation

System Requirements
  • Operating System: Linux, macOS, Windows
  • Go Version: 1.19 or higher
  • Dependencies: Self-contained WebRTC library (based on commit: d8dd1409d661), no additional system dependencies required.
Installation Steps
  1. Install the Go package
go get github.com/CoyAce/apm
  1. Import in your project
import "github.com/CoyAce/apm"
  1. Example
config := apm.Config{
		CaptureChannels:       1,
		RenderChannels:        1,
		HighPassFilterEnabled: true,
		EchoCancellation:      apm.EchoCancellationConfig{Enabled: true, MobileMode: mobile, StreamDelayMs: 54},
		NoiseSuppression:      apm.NoiseSuppressionConfig{Enabled: true, SuppressionLevel: apm.NsLevelModerate},
		GainControl: apm.GainControlConfig{
			Enabled:                      true,
			InputVolumeControllerEnabled: true,
			HeadroomDB:                   15,
			MaxGainDb:                    50,
		},
	}
processor, _ := apm.New(config)
processor.SetStreamAnalogLevel(180)

// add far end
_ = ae.processor.ProcessRenderInt16(farEnd)

// process near end
ae.processor.SetStreamDelay(config.EchoCancellation.StreamDelayMs)
_ := ae.processor.ProcessCapture(output)

Documentation

Overview

Package apm provides a Go wrapper for WebRTC's AudioProcessing module.

This package enables high-quality audio processing including echo cancellation, noise suppression, automatic gain control, and voice activity detection.

Example usage: 

processor, err := apm.New(apm.Config{
    SampleRateHz: 48000,
    NumChannels:  1,
    EchoCancellation: &apm.EchoCancellationConfig{
        Enabled:          true,
        SuppressionLevel: apm.SuppressionHigh,
    },
    NoiseSuppression: &apm.NoiseSuppressionConfig{
        Enabled: true,
        Level:   apm.NoiseSuppressionHigh,
    },
})
if err != nil {
    log.Fatal(err)
}
defer processor.Close()

// Process audio frames...
cleanSamples, hasVoice, err := processor.ProcessCapture(micSamples)

Package cgo provides low-level CGO bindings to the WebRTC AudioProcessing module.

Index

Constants

View Source 
const (
	SampleRateHz       = C.APM_SAMPLE_RATE_HZ
	FrameMs            = C.APM_FRAME_MS
	NumSamplesPerFrame = C.APM_NUM_SAMPLES_PER_FRAME
)

Constants exported from the C library

Variables

This section is empty.

Functions

func GetNumSamplesPerFrame 

func GetNumSamplesPerFrame() int

GetNumSamplesPerFrame returns the number of samples per frame

func GetSampleRateHz 

func GetSampleRateHz() int

GetSampleRateHz returns the sample rate in Hz

Types

type AnalogMicGainEmulationConfig added in v0.1.1 

type AnalogMicGainEmulationConfig struct {
	Enabled bool
	// Initial analog gain level to use for the emulated analog gain. Must
	// be in the range [0...255].
	InitialLevel int
}

type CaptureLevelAdjustmentConfig added in v0.1.1 

type CaptureLevelAdjustmentConfig struct {
	Enabled                bool
	PreGainFactor          float32
	PostGainFactor         float32
	AnalogMicGainEmulation AnalogMicGainEmulationConfig
}

type Config 

type Config struct {
	CaptureLevelAdjustment CaptureLevelAdjustmentConfig
	EchoCancellation       EchoCancellationConfig
	GainControl            GainControlConfig
	NoiseSuppression       NoiseSuppressionConfig
	HighPassFilterEnabled  bool
	CaptureChannels        int
	RenderChannels         int
}

Config holds all runtime configuration options

type EchoCancellationConfig 

type EchoCancellationConfig struct {
	Enabled       bool
	MobileMode    bool
	StreamDelayMs int // nil means use delay-agnostic mode
}

EchoCancellationConfig holds echo cancellation settings

type GainControlConfig 

type GainControlConfig struct {
	Enabled                      bool
	InputVolumeControllerEnabled bool
	HeadroomDB                   float32
	MaxGainDB                    float32
	GainDB                       float32
}

GainControlConfig holds automatic gain control settings

type Handle 

type Handle struct {
	// contains filtered or unexported fields
}

Handle represents an opaque handle to the audio processor

func Create 

func Create(config Config) (*Handle, error)

Create creates a new audio processor with the given initialization config

func (*Handle) ApplyConfig 

func (h *Handle) ApplyConfig(config Config)

ApplyConfig updates the runtime configuration

func (*Handle) Destroy 

func (h *Handle) Destroy()

Destroy releases the audio processor resources

func (*Handle) GetStats 

func (h *Handle) GetStats() Stats

GetStats returns statistics from the last capture frame processing

func (*Handle) Initialize 

func (h *Handle) Initialize()

func (*Handle) ProcessCaptureFrame 

func (h *Handle) ProcessCaptureFrame(samples []float32, numChannels int) error

ProcessCaptureFrame processes a capture (microphone) frame samples should be interleaved float32 samples with length = numChannels * NumSamplesPerFrame

func (*Handle) ProcessCaptureIntFrame added in v0.1.0 

func (h *Handle) ProcessCaptureIntFrame(samples []int16, numChannels int) error

func (*Handle) ProcessRenderFrame 

func (h *Handle) ProcessRenderFrame(samples []float32, numChannels int) error

ProcessRenderFrame processes a render (speaker) frame for echo cancellation samples should be interleaved float32 samples with length = numChannels * NumSamplesPerFrame

func (*Handle) ProcessRenderIntFrame added in v0.1.0 

func (h *Handle) ProcessRenderIntFrame(samples []int16, numChannels int) error

func (*Handle) RecommendedStreamAnalogLevel added in v0.1.1 

func (h *Handle) RecommendedStreamAnalogLevel() int

func (*Handle) SetOutputWillBeMuted 

func (h *Handle) SetOutputWillBeMuted(muted bool)

SetOutputWillBeMuted signals that output will be muted (hint for AEC/AGC)

func (*Handle) SetStreamAnalogLevel added in v0.1.1 

func (h *Handle) SetStreamAnalogLevel(level int)

func (*Handle) SetStreamDelayMs 

func (h *Handle) SetStreamDelayMs(delayMs int)

SetStreamDelayMs sets the delay between render and capture streams

func (*Handle) SetStreamKeyPressed 

func (h *Handle) SetStreamKeyPressed(pressed bool)

SetStreamKeyPressed signals that a key is being pressed (hint for AEC)

func (*Handle) StreamDelayMs 

func (h *Handle) StreamDelayMs() int

type NoiseSuppressionConfig 

type NoiseSuppressionConfig struct {
	Enabled          bool
	SuppressionLevel NsLevel
}

NoiseSuppressionConfig holds noise suppression settings

type NsLevel 

type NsLevel int

NsLevel represents noise suppression levels 

const (
	NsLevelLow      NsLevel = C.NS_LEVEL_LOW
	NsLevelModerate NsLevel = C.NS_LEVEL_MODERATE
	NsLevelHigh     NsLevel = C.NS_LEVEL_HIGH
	NsLevelVeryHigh NsLevel = C.NS_LEVEL_VERY_HIGH
)

type Processor 

type Processor struct {
	// contains filtered or unexported fields
}

Processor is the main APM instance

func New 

func New(config Config) (*Processor, error)

New creates a new audio processor with the given configuration

func (*Processor) Close 

func (p *Processor) Close() error

Close releases resources associated with the processor

func (*Processor) GetStats 

func (p *Processor) GetStats() Stats

GetStats returns statistics from the last ProcessCapture call

func (*Processor) Initialize added in v0.0.2 

func (p *Processor) Initialize()

func (*Processor) ProcessCapture 

func (p *Processor) ProcessCapture(samples []float32) error

ProcessCapture processes microphone input (near-end signal) Returns processed audio and voice activity detection result Input samples should be float32 in range [-1.0, 1.0]

func (*Processor) ProcessCaptureInt16 

func (p *Processor) ProcessCaptureInt16(samples []int16) error

ProcessCaptureInt16 processes microphone input with int16 samples

func (*Processor) ProcessRender 

func (p *Processor) ProcessRender(samples []float32) error

ProcessRender provides speaker output (far-end signal) for echo cancellation Must be called with speaker audio BEFORE ProcessCapture for the corresponding frame

func (*Processor) ProcessRenderInt16 

func (p *Processor) ProcessRenderInt16(samples []int16) error

ProcessRenderInt16 provides speaker output with int16 samples

func (*Processor) RecommendedStreamAnalogLevel added in v0.1.1 

func (p *Processor) RecommendedStreamAnalogLevel() int

func (*Processor) SetKeyPressed 

func (p *Processor) SetKeyPressed(pressed bool)

SetKeyPressed signals that a key is being pressed (hint for AEC)

func (*Processor) SetOutputMuted 

func (p *Processor) SetOutputMuted(muted bool)

SetOutputMuted signals that output will be muted (hint for AEC/AGC)

func (*Processor) SetStreamAnalogLevel added in v0.1.1 

func (p *Processor) SetStreamAnalogLevel(level int)

func (*Processor) SetStreamDelay 

func (p *Processor) SetStreamDelay(delayMs int)

SetStreamDelay updates the estimated delay between render and capture

func (*Processor) StreamDelay added in v0.0.2 

func (p *Processor) StreamDelay() int

type Stats 

type Stats struct {
	ResidualEchoLikelihood    float64
	DivergentFilterFraction   float64
	EchoReturnLoss            float64
	EchoReturnLossEnhancement float64
	DelayMedianMs             int
	DelayStdMs                int
	DelayMs                   int
}

Stats holds statistics from the audio processor

Source Files

View all Source files

Directories

Path Synopsis
examples
echo_cancellation command
Example: Echo cancellation
 Example: Echo cancellation
full_pipeline command
Example: Full audio processing pipeline
 Example: Full audio processing pipeline
noise_suppression command
Example: Noise suppression
 Example: Noise suppression
google.com
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abseil-cpp/absl/container
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abseil-cpp/absl/crc
abseil-cpp/absl/crc/internal
abseil-cpp/absl/debugging
abseil-cpp/absl/debugging/internal
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abseil-cpp/absl/functional
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abseil-cpp/absl/numeric
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abseil-cpp/absl/profiling/internal
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abseil-cpp/absl/synchronization/internal
abseil-cpp/absl/time
abseil-cpp/absl/time/internal
abseil-cpp/absl/time/internal/cctz/src
webrtc
webrtc/api
webrtc/api/audio
webrtc/api/environment
webrtc/api/rtc_event_log
webrtc/api/task_queue
webrtc/api/transport
webrtc/api/units
webrtc/audio_coding
webrtc/audio_coding/codecs/isac/main/source
webrtc/audio_processing
webrtc/audio_processing/aec3
webrtc/audio_processing/aecm
webrtc/audio_processing/agc
webrtc/audio_processing/agc/legacy
webrtc/audio_processing/agc2
webrtc/audio_processing/agc2/rnn_vad
webrtc/audio_processing/capture_levels_adjuster
webrtc/audio_processing/echo_detector
webrtc/audio_processing/include
webrtc/audio_processing/logging
webrtc/audio_processing/ns
webrtc/audio_processing/utility
webrtc/audio_processing/utility/pffft
webrtc/audio_processing/vad
webrtc/common_audio
webrtc/common_audio/resampler
webrtc/common_audio/signal_processing
webrtc/common_audio/third_party/ooura/fft_size_128
webrtc/common_audio/third_party/ooura/fft_size_256
webrtc/common_audio/third_party/spl_sqrt_floor
webrtc/common_audio/vad
webrtc/rtc_base
webrtc/rtc_base/containers
webrtc/rtc_base/experiments
webrtc/rtc_base/memory
webrtc/rtc_base/strings
webrtc/rtc_base/synchronization
webrtc/rtc_base/system
webrtc/sdk/android/native_api/stacktrace
webrtc/system_wrappers/source
webrtc/third_party
webrtc/third_party/fft
webrtc/third_party/rnnoise/src

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