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openaptx.h(3)

openaptx.h(3) Library Functions Manual openaptx.h(3)

NAME

openaptx.h - Reverse-engineered apt-X header file.

SYNOPSIS

#include <stddef.h>
#include <stdint.h>

Macros


#define OPENAPTX_API_WEAK __attribute__((weak))

Typedefs


typedef void * APTXENC
typedef void * APTXDEC

Functions


int aptxbtenc_init (APTXENC enc, short endian)
int aptxhdbtenc_init (APTXENC enc, short endian)
int aptxbtdec_init (APTXDEC dec, short endian)
int aptxhdbtdec_init (APTXDEC dec, short endian)
void aptxbtenc_destroy (APTXENC enc) OPENAPTX_API_WEAK
void aptxhdbtenc_destroy (APTXENC enc) OPENAPTX_API_WEAK
void aptxbtdec_destroy (APTXDEC dec)
void aptxhdbtdec_destroy (APTXDEC dec)
int aptxbtenc_encodestereo (APTXENC enc, const int32_t pcmL[4], const int32_t pcmR[4], uint16_t code[2])
int aptxhdbtenc_encodestereo (APTXENC enc, const int32_t pcmL[4], const int32_t pcmR[4], uint32_t code[2])
int aptxbtdec_decodestereo (APTXDEC dec, int32_t pcmL[4], int32_t pcmR[4], const uint16_t code[2])
int aptxhdbtdec_decodestereo (APTXDEC dec, int32_t pcmL[4], int32_t pcmR[4], const uint32_t code[2])
const char * aptxbtenc_build (void)
const char * aptxhdbtenc_build (void)
const char * aptxbtdec_build (void)
const char * aptxhdbtdec_build (void)
const char * aptxbtenc_version (void)
const char * aptxhdbtenc_version (void)
const char * aptxbtdec_version (void)
const char * aptxhdbtdec_version (void)
size_t SizeofAptxbtenc (void)
size_t SizeofAptxhdbtenc (void)
size_t SizeofAptxbtdec (void)
size_t SizeofAptxhdbtdec (void)
APTXENC NewAptxEnc (short endian) __attribute__((deprecated))
APTXENC NewAptxhdEnc (short endian) __attribute__((deprecated))

Detailed Description

Reverse-engineered apt-X header file.

This file is a part of [open]aptx.

Copyright

This project is licensed under the terms of the MIT license.

Note

The [open]aptx header file is based on the reverse-engineered proprietary library, which is currently owned by Qualcomm. The apt-X library itself is copyrighted under the terms of the Qualcomm Technologies, Inc.

Typedef Documentation

typedef void* APTXENC

Encoder handler.

typedef void* APTXDEC

Decoder handler.

Function Documentation

int aptxbtenc_init (APTXENC enc, short endian)

Initialize encoder structure.

Encoder handler shall be properly allocated before passing it to this function. To do so, one should use malloc(SizeofAptxbtenc()).

The apt-X stream shall contain codewords in the big-endian byte order. On the little-endian hosts one can set the swap parameter to true in order to obtain stream-ready codewords. Otherwise, swapping shall be done in the client code.

Parameters

enc Apt-X encoder handler.
endian Endianess of the output data, where 0 is for little-endian and big-endian otherwise.

Returns

On success 0 is returned.

int aptxhdbtenc_init (APTXENC enc, short endian)

Initialize encoder structure (HD variant).

Warning

Due to library bug, always set swap parameter to false.

Parameters

enc Apt-X encoder handler.
endian Endianess of the output data, where 0 is for little-endian and big-endian otherwise. DO NOT use it! It seems that there is a bug in the library which messes up the output if big-endian is enabled.

Returns

On success 0 is returned.

int aptxbtdec_init (APTXDEC dec, short endian)

Initialize decoder structure.

Decoder handler shall be properly allocated before passing it to this function. To do so, one should use malloc(SizeofAptxbtdec()).

The apt-X stream contains codewords in the big-endian byte order. However, the library expects codewords to be in the host native byte order. On the little-endian hosts one can set the swap parameter to true in order to perform swapping in the library code.

Parameters

dec Apt-X decoder handler.
endian Endianess of the input data, where 0 is for little-endian and big-endian otherwise.

Returns

On success 0 is returned.

int aptxhdbtdec_init (APTXDEC dec, short endian)

Initialize decoder structure (HD variant).

Parameters

dec Apt-X decoder handler.
endian Endianess of the input data, where 0 is for little-endian and big-endian otherwise.

Returns

On success 0 is returned.

void aptxbtenc_destroy (APTXENC enc)

Destroy encoder structure.

Since

This function is available since apt-X Adaptive library.

Parameters

enc Initialized encoder handler or NULL.

void aptxhdbtenc_destroy (APTXENC enc)

Destroy encoder structure (HD variant).

Since

This function is available since apt-X Adaptive library.

Parameters

enc Initialized encoder handler or NULL.

void aptxbtdec_destroy (APTXDEC dec)

Destroy decoder structure.

Parameters

dec Initialized decoder handler or NULL.

void aptxhdbtdec_destroy (APTXDEC dec)

Destroy decoder structure (HD variant).

Parameters

dec Initialized decoder handler or NULL.

int aptxbtenc_encodestereo (APTXENC enc, const int32_t pcmL[4], const int32_t pcmR[4], uint16_t code[2])

Encode stereo PCM data.

Parameters

enc Initialized encoder handler.
pcmL Four 16-bit audio samples for left channel.
pcmR Four 16-bit audio samples for right channel.
code Two 16-bit codewords with auto-sync inserted.

Returns

On success 0 is returned.

int aptxhdbtenc_encodestereo (APTXENC enc, const int32_t pcmL[4], const int32_t pcmR[4], uint32_t code[2])

Encode stereo PCM data (HD variant).

The 24-bit codeword will be placed in the lower bytes of the 32-bit output parameter. Note, that the apt-X stream assumes big-endian byte ordering. In order to safely extract data, one can use shift operation, e.g.:

uint8_t stream[] = { code[0] >> 16, code[0] >> 8, code[0], code[1] >> 16, code[1] >> 8, code[1] };

Parameters

enc Initialized encoder handler.
pcmL Four 24-bit audio samples for left channel.
pcmR Four 24-bit audio samples for right channel.
code Two 24-bit codewords with auto-sync inserted.

Returns

On success 0 is returned.

int aptxbtdec_decodestereo (APTXDEC dec, int32_t pcmL[4], int32_t pcmR[4], const uint16_t code[2])

Decode stereo PCM data.

Parameters

dec Initialized decoder handler.
pcmL Four 16-bit audio samples for left channel.
pcmR Four 16-bit audio samples for right channel.
code Two 16-bit codewords.

Returns

On success 0 is returned.

int aptxhdbtdec_decodestereo (APTXDEC dec, int32_t pcmL[4], int32_t pcmR[4], const uint32_t code[2])

Decode stereo PCM data (HD variant).

The 24-bit codeword shall be placed in the lower bytes of the 32-bit input parameter. Note, that the apt-X stream contains codewords in the big-endian byte ordering. Assuming that the swap parameter for aptxhdbtdec_init() was set to false, in order to safely pass data one can use shift operation like follows:

uint32_t code[2] = { (stream[0] << 16) || (stream[1] << 8) || stream[2], (stream[3] << 16) || (stream[4] << 8) || stream[5] };

Parameters

dec Initialized decoder handler.
pcmL Four 24-bit audio samples for left channel.
pcmR Four 24-bit audio samples for right channel.
code Two 24-bit codewords.

Returns

On success 0 is returned.

const char * aptxbtenc_build (void )

Encoder library build name.

const char * aptxhdbtenc_build (void )

Encoder library build name (HD variant).

const char * aptxbtdec_build (void )

Decoder library build name.

const char * aptxhdbtdec_build (void )

Decoder library build name (HD variant).

const char * aptxbtenc_version (void )

Encoder library version number.

const char * aptxhdbtenc_version (void )

Encoder library version number (HD variant).

const char * aptxbtdec_version (void )

Decoder library version number.

const char * aptxhdbtdec_version (void )

Decoder library version number (HD variant).

size_t SizeofAptxbtenc (void )

Get the size of the encoder structure.

size_t SizeofAptxhdbtenc (void )

Get the size of the encoder structure (HD variant).

size_t SizeofAptxbtdec (void )

Get the size of the decoder structure.

size_t SizeofAptxhdbtdec (void )

Get the size of the decoder structure (HD variant).

APTXENC NewAptxEnc (short endian)

Get initialized encoder structure.

Note

This function is NOT thread-safe.

Deprecated

Please use aptxbtenc_init() instead.

Parameters

endian Endianess of the input data, where 0 is for little-endian and big-endian otherwise.

Returns

This function returns an address to the statically allocated encoder structure. Do not pass this handler to the free() function.

APTXENC NewAptxhdEnc (short endian)

Get initialized encoder structure (HD variant).

Note

This function is NOT thread-safe.

Deprecated

Please use aptxhdbtenc_init() instead.

Parameters

endian Endianess of the input data, where 0 is for little-endian and big-endian otherwise.

Returns

This function returns an address to the statically allocated encoder structure. Do not pass this handler to the free() function.

Author

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Version 2.0.0 [open]aptx