vadpcm

Documentation

Overview

Package vadpcm provides tools for working with VADPCM-encoded audio.

Index

• Constants
• func Decode(codebook *Codebook, state *Vector, dest []int16, src []byte) (int, error)
• type Codebook
  • func Encode(params *Parameters, data []int16) (*Codebook, []byte, error)
• type Parameters
• type Vector

Constants

const CompressionName = "VADPCM ~4-1"

CompressionName is the descriptive name used to represent VADPCM compression.

const CompressionType = "VAPC"

CompressionType is the four-character code used to represent VADPCM compression.

const EncodeOrder = C.kVADPCMEncodeOrder

EncodeOrder is the predictor order when encoding. Other values are not supported. Do not change this value.

const FrameByteSize = C.kVADPCMFrameByteSize

FrameByteSize is the number of bytes in an encoded VADPCM frame.

const FrameSampleCount = C.kVADPCMFrameSampleCount

FrameSampleCount is the number of samples in a VADPCM frame.

const MaxOrder = C.kVADPCMMaxOrder

MaxOrder maximum supported predictor order. Do not change this value. This is chosen to make the decoder state the same size as a 128-bit vector.

const MaxPredictorCount = C.kVADPCMMaxPredictorCount

MaxPredictorCount is the maximum supported number of predictors. This is limited by the format of VADPCM frames, which only use four bits to encode the predictor index.

const VectorSize = 8

VectorSize is the number of elements in a VADPCM vector.

Functions

func Decode

func Decode(codebook *Codebook, state *Vector, dest []int16, src []byte) (int, error)

Decode decodes VADPCM-encoded audio data. Returns the number of frames decoded.

Types

type Codebook

type Codebook struct {
	Order          int
	PredictorCount int
	Vectors        []Vector
}

func Encode

func Encode(params *Parameters, data []int16) (*Codebook, []byte, error)

Encode encodes audio as VADPCM.

type Parameters

type Parameters struct {
	PredictorCount int
}

Parameters contains the parameters for encoding,

type Vector

type Vector [VectorSize]int16