Typedefs
typedef struct ima_adpcm_state_s	ima_adpcm_state_t

Enumerations
enum	{ IMA_ADPCM_IMA4 = 0 , IMA_ADPCM_DVI4 = 1 , IMA_ADPCM_VDVI = 2 }

Functions
ima_adpcm_state_t *	ima_adpcm_init (ima_adpcm_state_t *s, int variant, int chunk_size)
int	ima_adpcm_release (ima_adpcm_state_t *s)
int	ima_adpcm_free (ima_adpcm_state_t *s)
int	ima_adpcm_encode (ima_adpcm_state_t *s, uint8_t ima_data[], const int16_t amp[], int len)
int	ima_adpcm_decode (ima_adpcm_state_t *s, int16_t amp[], const uint8_t ima_data[], int ima_bytes)

Typedef Documentation

◆ ima_adpcm_state_t

typedef struct ima_adpcm_state_s ima_adpcm_state_t

IMA (DVI/Intel) ADPCM conversion state descriptor. This defines the state of a single working instance of the IMA ADPCM converter. This is used for either linear to ADPCM or ADPCM to linear conversion.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

Enumerator
IMA_ADPCM_IMA4	IMA4 is the original IMA ADPCM variant
IMA_ADPCM_DVI4	DVI4 is the IMA ADPCM variant defined in RFC3551
IMA_ADPCM_VDVI	VDVI is the variable bit rate IMA ADPCM variant defined in RFC3551

Function Documentation

◆ ima_adpcm_decode()

int ima_adpcm_decode	(	ima_adpcm_state_t *	s,
		int16_t	amp[],
		const uint8_t	ima_data[],
		int	ima_bytes )

Decode a buffer of IMA ADPCM data to linear PCM.

Parameters

s	The IMA ADPCM context.
amp	The audio sample buffer.
ima_data	The IMA ADPCM data
ima_bytes	The number of bytes of IMA ADPCM data

Returns: The number of samples returned.

References ima_adpcm_state_s::chunk_size, ima_adpcm_decode(), IMA_ADPCM_DVI4, IMA_ADPCM_IMA4, IMA_ADPCM_VDVI, ima_adpcm_state_s::last, and ima_adpcm_state_s::step_index.

Referenced by ima_adpcm_decode().

◆ ima_adpcm_encode()

int ima_adpcm_encode	(	ima_adpcm_state_t *	s,
		uint8_t	ima_data[],
		const int16_t	amp[],
		int	len )

Encode a buffer of linear PCM data to IMA ADPCM.

Parameters

s	The IMA ADPCM context.
ima_data	The IMA ADPCM data produced.
amp	The audio sample buffer.
len	The number of samples in the buffer.

Returns: The number of bytes of IMA ADPCM data produced.

References ima_adpcm_state_s::chunk_size, IMA_ADPCM_DVI4, ima_adpcm_encode(), IMA_ADPCM_IMA4, IMA_ADPCM_VDVI, ima_adpcm_state_s::ima_byte, ima_adpcm_state_s::last, and ima_adpcm_state_s::step_index.

Referenced by ima_adpcm_encode().

◆ ima_adpcm_free()

int ima_adpcm_free ( ima_adpcm_state_t * s )

Free an IMA ADPCM encode or decode context.

Parameters

s	The IMA ADPCM context.

Returns: 0 for OK.

References ima_adpcm_free().

Referenced by ima_adpcm_free().

◆ ima_adpcm_init()

ima_adpcm_state_t * ima_adpcm_init	(	ima_adpcm_state_t *	s,
		int	variant,
		int	chunk_size )

Initialise an IMA ADPCM encode or decode context.

Parameters

s	The IMA ADPCM context.
variant	IMA_ADPCM_IMA4, IMA_ADPCM_DVI4, or IMA_ADPCM_VDVI.
chunk_size	The size of a chunk, in samples. A chunk size of zero sample samples means treat each encode or decode operation as a chunk.