libcelt/celt.h

/* Copyright (c) 2007-2008 CSIRO
   Copyright (c) 2007-2009 Xiph.Org Foundation
   Copyright (c) 2008 Gregory Maxwell 
   Written by Jean-Marc Valin and Gregory Maxwell */
/**
  @file celt.h
  @brief Contains all the functions for encoding and decoding audio
 */

/*
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
   
   - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
   
   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
   
   - Neither the name of the Xiph.org Foundation nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.
   
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef CELT_H
#define CELT_H

#include "celt_types.h"

#ifdef __cplusplus
extern "C" {
#endif

#if defined(__GNUC__) && defined(CELT_BUILD)
#define EXPORT __attribute__ ((visibility ("default")))
#elif defined(WIN32)
#define EXPORT __declspec(dllexport)
#else
#define EXPORT
#endif

#define _celt_check_int(x) (((void)((x) == (celt_int32)0)), (celt_int32)(x))
#define _celt_check_mode_ptr_ptr(ptr) ((ptr) + ((ptr) - (CELTMode**)(ptr)))

/* Error codes */
/** No error */
#define CELT_OK                0
/** An (or more) invalid argument (e.g. out of range) */
#define CELT_BAD_ARG          -1
/** The mode struct passed is invalid */
#define CELT_INVALID_MODE     -2
/** An internal error was detected */
#define CELT_INTERNAL_ERROR   -3
/** The data passed (e.g. compressed data to decoder) is corrupted */
#define CELT_CORRUPTED_DATA   -4
/** Invalid/unsupported request number */
#define CELT_UNIMPLEMENTED    -5
/** An encoder or decoder structure is invalid or already freed */
#define CELT_INVALID_STATE    -6
/** Memory allocation has failed */
#define CELT_ALLOC_FAIL       -7

/* Requests */
#define CELT_GET_MODE_REQUEST    1
/** Get the CELTMode used by an encoder or decoder */
#define CELT_GET_MODE(x) CELT_GET_MODE_REQUEST, _celt_check_mode_ptr_ptr(x)
#define CELT_SET_COMPLEXITY_REQUEST    2
/** Controls the complexity from 0-10 (int) */
#define CELT_SET_COMPLEXITY(x) CELT_SET_COMPLEXITY_REQUEST, _celt_check_int(x)
#define CELT_SET_PREDICTION_REQUEST    4
/** Controls the use of interframe prediction.
    0=Independent frames
    1=Short term interframe prediction allowed
    2=Long term prediction allowed
 */
#define CELT_SET_PREDICTION(x) CELT_SET_PREDICTION_REQUEST, _celt_check_int(x)
#define CELT_SET_VBR_RATE_REQUEST    6
/** Set the target VBR rate in bits per second(int); 0=CBR (default) */
#define CELT_SET_VBR_RATE(x) CELT_SET_VBR_RATE_REQUEST, _celt_check_int(x)
/** Reset the encoder/decoder memories to zero*/
#define CELT_RESET_STATE_REQUEST        8
#define CELT_RESET_STATE       CELT_RESET_STATE_REQUEST

#define CELT_SET_START_BAND_REQUEST    10000
#define CELT_SET_START_BAND(x) CELT_SET_START_BAND_REQUEST, _celt_check_int(x)

#define CELT_SET_END_BAND_REQUEST    10001
#define CELT_SET_END_BAND(x) CELT_SET_END_BAND_REQUEST, _celt_check_int(x)

/** GET the lookahead used in the current mode */
#define CELT_GET_LOOKAHEAD    1001
/** GET the sample rate used in the current mode */
#define CELT_GET_SAMPLE_RATE  1003

/** GET the bit-stream version for compatibility check */
#define CELT_GET_BITSTREAM_VERSION 2000


/** Contains the state of an encoder. One encoder state is needed 
    for each stream. It is initialised once at the beginning of the
    stream. Do *not* re-initialise the state for every frame.
   @brief Encoder state
 */
typedef struct CELTEncoder CELTEncoder;

/** State of the decoder. One decoder state is needed for each stream.
    It is initialised once at the beginning of the stream. Do *not*
    re-initialise the state for every frame */
typedef struct CELTDecoder CELTDecoder;

/** The mode contains all the information necessary to create an
    encoder. Both the encoder and decoder need to be initialised
    with exactly the same mode, otherwise the quality will be very 
    bad */
typedef struct CELTMode CELTMode;


/** \defgroup codec Encoding and decoding */
/*  @{ */

/* Mode calls */

/** Creates a new mode struct. This will be passed to an encoder or 
    decoder. The mode MUST NOT BE DESTROYED until the encoders and 
    decoders that use it are destroyed as well.
 @param Fs Sampling rate (32000 to 96000 Hz)
 @param frame_size Number of samples (per channel) to encode in each 
                   packet (even values; 64 - 512)
 @param error Returned error code (if NULL, no error will be returned)
 @return A newly created mode
*/
EXPORT CELTMode *celt_mode_create(celt_int32 Fs, int frame_size, int *error);

/** Destroys a mode struct. Only call this after all encoders and 
    decoders using this mode are destroyed as well.
 @param mode Mode to be destroyed
*/
EXPORT void celt_mode_destroy(CELTMode *mode);

/** Query information from a mode */
EXPORT int celt_mode_info(const CELTMode *mode, int request, celt_int32 *value);

/* Encoder stuff */

EXPORT int celt_encoder_get_size(const CELTMode *mode, int channels);

/** Creates a new encoder state. Each stream needs its own encoder 
    state (can't be shared across simultaneous streams).
 @param mode Contains all the information about the characteristics of
 *  the stream (must be the same characteristics as used for the 
 *  decoder)
 @param channels Number of channels
 @param error Returns an error code
 @return Newly created encoder state.
*/
EXPORT CELTEncoder *celt_encoder_create(const CELTMode *mode, int channels, int *error);

EXPORT CELTEncoder *celt_encoder_init(CELTEncoder *st, const CELTMode *mode, int channels, int *error);

/** Destroys a an encoder state.
 @param st Encoder state to be destroyed
 */
EXPORT void celt_encoder_destroy(CELTEncoder *st);

/** Encodes a frame of audio.
 @param st Encoder state
 @param pcm PCM audio in float format, with a normal range of ±1.0. 
 *          Samples with a range beyond ±1.0 are supported but will 
 *          be clipped by decoders using the integer API and should 
 *          only be used if it is known that the far end supports 
 *          extended dynmaic range. There must be exactly
 *          frame_size samples per channel. 
 @param optional_resynthesis If not NULL, the encoder copies the audio signal that
 *          the decoder would decode. It is the same as calling the
 *          decoder on the compressed data, just faster.
 *          This may alias pcm. 
 @param compressed The compressed data is written here. This may not alias pcm or
 *                 optional_synthesis.
 @param nbCompressedBytes Maximum number of bytes to use for compressing the frame
 *          (can change from one frame to another)
 @return Number of bytes written to "compressed". Will be the same as 
 *       "nbCompressedBytes" unless the stream is VBR and will never be larger.
 *       If negative, an error has occurred (see error codes). It is IMPORTANT that
 *       the length returned be somehow transmitted to the decoder. Otherwise, no
 *       decoding is possible.
*/
EXPORT int celt_encode_resynthesis_float(CELTEncoder *st, const float *pcm, float *optional_resynthesis, int frame_size, unsigned char *compressed, int nbCompressedBytes);

/** Encodes a frame of audio.
 @param st Encoder state
 @param pcm PCM audio in float format, with a normal range of ±1.0.
 *          Samples with a range beyond ±1.0 are supported but will
 *          be clipped by decoders using the integer API and should
 *          only be used if it is known that the far end supports
 *          extended dynmaic range. There must be exactly
 *          frame_size samples per channel.
 @param compressed The compressed data is written here. This may not alias pcm or
 *                 optional_synthesis.
 @param nbCompressedBytes Maximum number of bytes to use for compressing the frame
 *          (can change from one frame to another)
 @return Number of bytes written to "compressed". Will be the same as
 *       "nbCompressedBytes" unless the stream is VBR and will never be larger.
 *       If negative, an error has occurred (see error codes). It is IMPORTANT that
 *       the length returned be somehow transmitted to the decoder. Otherwise, no
 *       decoding is possible.
*/
EXPORT int celt_encode_float(CELTEncoder *st, const float *pcm, int frame_size, unsigned char *compressed, int nbCompressedBytes);

/** Encodes a frame of audio.
 @param st Encoder state
 @param pcm PCM audio in signed 16-bit format (native endian). There must be 
 *          exactly frame_size samples per channel. 
 @param optional_resynthesis If not NULL, the encoder copies the audio signal that
 *                         the decoder would decode. It is the same as calling the
 *                         decoder on the compressed data, just faster.
 *                         This may alias pcm. 
 @param compressed The compressed data is written here. This may not alias pcm or
 *                         optional_synthesis.
 @param nbCompressedBytes Maximum number of bytes to use for compressing the frame
 *                        (can change from one frame to another)
 @return Number of bytes written to "compressed". Will be the same as 
 *       "nbCompressedBytes" unless the stream is VBR and will never be larger.
 *       If negative, an error has occurred (see error codes). It is IMPORTANT that
 *       the length returned be somehow transmitted to the decoder. Otherwise, no
 *       decoding is possible.
 */
EXPORT int celt_encode_resynthesis(CELTEncoder *st, const celt_int16 *pcm, celt_int16 *optional_resynthesis, int frame_size, unsigned char *compressed, int nbCompressedBytes);

/** Encodes a frame of audio.
 @param st Encoder state
 @param pcm PCM audio in signed 16-bit format (native endian). There must be
 *          exactly frame_size samples per channel.
 @param compressed The compressed data is written here. This may not alias pcm or
 *                         optional_synthesis.
 @param nbCompressedBytes Maximum number of bytes to use for compressing the frame
 *                        (can change from one frame to another)
 @return Number of bytes written to "compressed". Will be the same as
 *       "nbCompressedBytes" unless the stream is VBR and will never be larger.
 *       If negative, an error has occurred (see error codes). It is IMPORTANT that
 *       the length returned be somehow transmitted to the decoder. Otherwise, no
 *       decoding is possible.
 */
EXPORT int celt_encode(CELTEncoder *st, const celt_int16 *pcm, int frame_size, unsigned char *compressed, int nbCompressedBytes);

/** Query and set encoder parameters 
 @param st Encoder state
 @param request Parameter to change or query
 @param value Pointer to a 32-bit int value
 @return Error code
*/
EXPORT int celt_encoder_ctl(CELTEncoder * st, int request, ...);

/* Decoder stuff */

EXPORT int celt_decoder_get_size(const CELTMode *mode, int channels);

/** Creates a new decoder state. Each stream needs its own decoder state (can't
    be shared across simultaneous streams).
 @param mode Contains all the information about the characteristics of the
             stream (must be the same characteristics as used for the encoder)
 @param channels Number of channels
 @param error Returns an error code
 @return Newly created decoder state.
 */
EXPORT CELTDecoder *celt_decoder_create(const CELTMode *mode, int channels, int *error);

EXPORT CELTDecoder *celt_decoder_init(CELTDecoder *st, const CELTMode *mode, int channels, int *error);

/** Destroys a a decoder state.
 @param st Decoder state to be destroyed
 */
EXPORT void celt_decoder_destroy(CELTDecoder *st);

/** Decodes a frame of audio.
 @param st Decoder state
 @param data Compressed data produced by an encoder
 @param len Number of bytes to read from "data". This MUST be exactly the number
            of bytes returned by the encoder. Using a larger value WILL NOT WORK.
 @param pcm One frame (frame_size samples per channel) of decoded PCM will be
            returned here in float format. 
 @return Error code.
   */
EXPORT int celt_decode_float(CELTDecoder *st, const unsigned char *data, int len, float *pcm, int frame_size);

/** Decodes a frame of audio.
 @param st Decoder state
 @param data Compressed data produced by an encoder
 @param len Number of bytes to read from "data". This MUST be exactly the number
            of bytes returned by the encoder. Using a larger value WILL NOT WORK.
 @param pcm One frame (frame_size samples per channel) of decoded PCM will be
            returned here in 16-bit PCM format (native endian). 
 @return Error code.
 */
EXPORT int celt_decode(CELTDecoder *st, const unsigned char *data, int len, celt_int16 *pcm, int frame_size);

/** Query and set decoder parameters
   @param st Decoder state
   @param request Parameter to change or query
   @param value Pointer to a 32-bit int value
   @return Error code
 */
EXPORT int celt_decoder_ctl(CELTDecoder * st, int request, ...);


/** Returns the English string that corresponds to an error code
 * @param error Error code (negative for an error, 0 for success
 * @return Constant string (must NOT be freed)
 */
EXPORT const char *celt_strerror(int error);

/*  @} */


#ifdef __cplusplus
}
#endif

#endif /*CELT_H */