ima_adpcm.h File Reference

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Classes
struct	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_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)

---

Detailed Description

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Enumeration Type Documentation

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

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Function Documentation

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
	ima_bytes

Returns:

The number of samples returned.

References ima_adpcm_state_t::bits, ima_adpcm_state_t::chunk_size, IMA_ADPCM_DVI4, IMA_ADPCM_IMA4, IMA_ADPCM_VDVI, ima_adpcm_state_t::last, ima_adpcm_state_t::step_index, and ima_adpcm_state_t::variant.

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_t::bits, ima_adpcm_state_t::chunk_size, IMA_ADPCM_DVI4, IMA_ADPCM_IMA4, IMA_ADPCM_VDVI, ima_adpcm_state_t::ima_byte, ima_adpcm_state_t::last, ima_adpcm_state_t::step_index, and ima_adpcm_state_t::variant.

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	???
	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.

Returns:

A pointer to the IMA ADPCM context, or NULL for error.

References ima_adpcm_state_t::chunk_size, and ima_adpcm_state_t::variant.

int ima_adpcm_release

(

ima_adpcm_state_t *

s

)

Free an IMA ADPCM encode or decode context.

Parameters:

s

The IMA ADPCM context.

Returns:

0 for OK.