aac

README

aac

This package provides a simple way to encode audio from gopxl/beep's Streamer interface directly to AAC format using the gen2brain/aac-go encoder.

Installation

go get -u github.com/thde/aac

Usage

package main

import (
    "os"

    "github.com/gopxl/beep/v2"
    "github.com/gopxl/beep/v2/wav"
    "github.com/thde/aac"
)

func main() {
    f, err := os.Open("input.wav")
    if err != nil {
        panic(err)
    }
    defer f.Close()

    streamer, format, err := wav.Decode(f)
    if err != nil {
        panic(err)
    }
    defer streamer.Close()

    out, err := os.Create("output.aac")
    if err != nil {
        panic(err)
    }
    defer out.Close()

    err = aac.Encode(out, streamer, aac.EncodeOptions{
        Format:  format,
        BitRate: 128000, // 128 kbps
    })
    if err != nil {
        panic(err)
    }
}

License

MIT

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Documentation

Overview

Package aac provides AAC encoding functionality for beep audio streams.

Index

• func Encode(w io.Writer, s beep.Streamer, opts EncodeOptions) error
• type EncodeOptions

Examples

• Encode

Functions

func Encode

func Encode(w io.Writer, s beep.Streamer, opts EncodeOptions) error

Encode writes a beep.Streamer to an io.Writer in AAC format. Returns an error if encoding fails, if the format has an unsupported precision, or if the format has more than 2 channels.

Example

Example demonstrates encoding generated audio (sine wave).

format := beep.Format{
	SampleRate:  44100,
	NumChannels: 2,
	Precision:   2,
}

// Generate a 440 Hz sine wave (A4 note) for 3 seconds
sine, err := generators.SineTone(format.SampleRate, 440)
if err != nil {
	log.Fatal(err)
}
limited := beep.Take(format.SampleRate.N(3*time.Second), sine)

// Create output file
out, err := os.Create("sine.aac")
if err != nil {
	log.Fatal(err)
}
defer out.Close()

// Encode to AAC
if err = aac.Encode(out, limited, aac.EncodeOptions{
	Format:  format,
	BitRate: 128000,
}); err != nil {
	log.Fatal(err)
}

Types

type EncodeOptions

type EncodeOptions struct {
	// Embed the source audio format. Precision must be 2 (16-bit PCM) to match the AAC encoder requirements.
	beep.Format
	// BitRate in bits/sec.
	// If 0, defaults to 64000 bits/sec.
	BitRate int
}

EncodeOptions defines the options for AAC encoding.