1/*
2** Copyright (C) 2002-2011 Erik de Castro Lopo <erikd@mega-nerd.com>
3**
4** This program is free software; you can redistribute it and/or modify
5** it under the terms of the GNU General Public License as published by
6** the Free Software Foundation; either version 2 of the License, or
7** (at your option) any later version.
8**
9** This program is distributed in the hope that it will be useful,
10** but WITHOUT ANY WARRANTY; without even the implied warranty of
11** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12** GNU General Public License for more details.
13**
14** You should have received a copy of the GNU General Public License
15** along with this program; if not, write to the Free Software
16** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
17*/
18
19/*
20** This code is part of Secret Rabbit Code aka libsamplerate. A commercial
21** use license for this code is available, please see:
22** http://www.mega-nerd.com/SRC/procedure.html
23*/
24
25/*
26** API documentation is available here:
27** http://www.mega-nerd.com/SRC/api.html
28*/
29
30#ifndef SAMPLERATE_H
31#define SAMPLERATE_H
32
33#ifdef __cplusplus
34extern "C" {
35#endif /* __cplusplus */
36
37
38/* Opaque data type SRC_STATE. */
39typedef struct SRC_STATE_tag SRC_STATE ;
40
41/* SRC_DATA is used to pass data to src_simple() and src_process(). */
42typedef struct
43{ float *data_in, *data_out ;
44
45 long input_frames, output_frames ;
46 long input_frames_used, output_frames_gen ;
47
48 int end_of_input ;
49
50 double src_ratio ;
51} SRC_DATA ;
52
53/* SRC_CB_DATA is used with callback based API. */
54typedef struct
55{ long frames ;
56 float *data_in ;
57} SRC_CB_DATA ;
58
59/*
60** User supplied callback function type for use with src_callback_new()
61** and src_callback_read(). First parameter is the same pointer that was
62** passed into src_callback_new(). Second parameter is pointer to a
63** pointer. The user supplied callback function must modify *data to
64** point to the start of the user supplied float array. The user supplied
65** function must return the number of frames that **data points to.
66*/
67
68typedef long (*src_callback_t) (void *cb_data, float **data) ;
69
70/*
71** Standard initialisation function : return an anonymous pointer to the
72** internal state of the converter. Choose a converter from the enums below.
73** Error returned in *error.
74*/
75
76SRC_STATE* src_new (int converter_type, int channels, int *error) ;
77
78/*
79** Initilisation for callback based API : return an anonymous pointer to the
80** internal state of the converter. Choose a converter from the enums below.
81** The cb_data pointer can point to any data or be set to NULL. Whatever the
82** value, when processing, user supplied function "func" gets called with
83** cb_data as first parameter.
84*/
85
86SRC_STATE* src_callback_new (src_callback_t func, int converter_type, int channels,
87 int *error, void* cb_data) ;
88
89/*
90** Cleanup all internal allocations.
91** Always returns NULL.
92*/
93
94SRC_STATE* src_delete (SRC_STATE *state) ;
95
96/*
97** Standard processing function.
98** Returns non zero on error.
99*/
100
101int src_process (SRC_STATE *state, SRC_DATA *data) ;
102
103/*
104** Callback based processing function. Read up to frames worth of data from
105** the converter int *data and return frames read or -1 on error.
106*/
107long src_callback_read (SRC_STATE *state, double src_ratio, long frames, float *data) ;
108
109/*
110** Simple interface for performing a single conversion from input buffer to
111** output buffer at a fixed conversion ratio.
112** Simple interface does not require initialisation as it can only operate on
113** a single buffer worth of audio.
114*/
115
116int src_simple (SRC_DATA *data, int converter_type, int channels) ;
117
118/*
119** This library contains a number of different sample rate converters,
120** numbered 0 through N.
121**
122** Return a string giving either a name or a more full description of each
123** sample rate converter or NULL if no sample rate converter exists for
124** the given value. The converters are sequentially numbered from 0 to N.
125*/
126
127const char *src_get_name (int converter_type) ;
128const char *src_get_description (int converter_type) ;
129const char *src_get_version (void) ;
130
131/*
132** Set a new SRC ratio. This allows step responses
133** in the conversion ratio.
134** Returns non zero on error.
135*/
136
137int src_set_ratio (SRC_STATE *state, double new_ratio) ;
138
139/*
140** Reset the internal SRC state.
141** Does not modify the quality settings.
142** Does not free any memory allocations.
143** Returns non zero on error.
144*/
145
146int src_reset (SRC_STATE *state) ;
147
148/*
149** Return TRUE if ratio is a valid conversion ratio, FALSE
150** otherwise.
151*/
152
153int src_is_valid_ratio (double ratio) ;
154
155/*
156** Return an error number.
157*/
158
159int src_error (SRC_STATE *state) ;
160
161/*
162** Convert the error number into a string.
163*/
164const char* src_strerror (int error) ;
165
166/*
167** The following enums can be used to set the interpolator type
168** using the function src_set_converter().
169*/
170
171enum
172{
173 SRC_SINC_BEST_QUALITY = 0,
174 SRC_SINC_MEDIUM_QUALITY = 1,
175 SRC_SINC_FASTEST = 2,
176 SRC_ZERO_ORDER_HOLD = 3,
177 SRC_LINEAR = 4,
178} ;
179
180/*
181** Extra helper functions for converting from short to float and
182** back again.
183*/
184
185void src_short_to_float_array (const short *in, float *out, int len) ;
186void src_float_to_short_array (const float *in, short *out, int len) ;
187
188void src_int_to_float_array (const int *in, float *out, int len) ;
189void src_float_to_int_array (const float *in, int *out, int len) ;
190
191
192#ifdef __cplusplus
193} /* extern "C" */
194#endif /* __cplusplus */
195
196#endif /* SAMPLERATE_H */
197
198