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{*
** Copyright (C) 2002-2004 Erik de Castro Lopo <erikd@mega-nerd.com>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*}
{*
** API documentation is available here:
** http://www.mega-nerd.com/SRC/api.html
*}
unit samplerate;
{$IFDEF FPC}
{$MODE DELPHI}
{$PACKENUM 4} (* use 4-byte enums *)
{$PACKRECORDS C} (* GCC/Visual C/C++ compatible record packing *)
{$ELSE}
{$MINENUMSIZE 4} (* use 4-byte enums *)
{$ENDIF}
interface
uses
ctypes,
UConfig;
const
{$IFDEF MSWINDOWS}
LibName = 'libsamplerate-0.dll';
{$ENDIF}
{$IFDEF UNIX}
LibName = 'samplerate';
{$IFDEF DARWIN}
{$LINKLIB libsamplerate}
{$ENDIF}
{$ENDIF}
{ Opaque data type SRC_STATE. }
type
PSRC_STATE = ^SRC_STATE;
SRC_STATE = record
// opaque
end;
{ SRC_DATA is used to pass data to src_simple() and src_process(). }
type
PSRC_DATA = ^SRC_DATA;
SRC_DATA = record
data_in, data_out: PCfloat;
input_frames, output_frames: clong;
input_frames_used, output_frames_gen: clong;
end_of_input: cint;
src_ratio: cdouble;
end;
{ SRC_CB_DATA is used with callback based API. }
type
SRC_CB_DATA = record
frames: clong;
data_in: PCfloat;
end;
{*
** User supplied callback function type for use with src_callback_new()
** and src_callback_read(). First parameter is the same pointer that was
** passed into src_callback_new(). Second parameter is pointer to a
** pointer. The user supplied callback function must modify *data to
** point to the start of the user supplied float array. The user supplied
** function must return the number of frames that **data points to.
*}
src_callback_t = function (cb_data: pointer; var data: PCfloat): clong; cdecl;
{*
** Standard initialisation function : return an anonymous pointer to the
** internal state of the converter. Choose a converter from the enums below.
** Error returned in *error.
*}
function src_new(converter_type: cint; channels: cint; error: PCint): PSRC_STATE; cdecl; external LibName;
{*
** Initilisation for callback based API : return an anonymous pointer to the
** internal state of the converter. Choose a converter from the enums below.
** The cb_data pointer can point to any data or be set to NULL. Whatever the
** value, when processing, user supplied function "func" gets called with
** cb_data as first parameter.
*}
function src_callback_new(func: src_callback_t; converter_type: cint; channels: cint;
error: Pinteger; cb_data: pointer): PSRC_STATE; cdecl; external LibName;
{*
** Cleanup all internal allocations.
** Always returns NULL.
*}
function src_delete(state: PSRC_STATE): PSRC_STATE; cdecl; external LibName;
{*
** Standard processing function.
** Returns non zero on error.
*}
function src_process(state: PSRC_STATE; data: PSRC_DATA): cint; cdecl; external LibName;
{*
** Callback based processing function. Read up to frames worth of data from
** the converter int *data and return frames read or -1 on error.
*}
function src_callback_read(state: PSRC_STATE; src_ratio: cdouble;
frames: clong; data: PCfloat): clong; cdecl; external LibName;
{*
** Simple interface for performing a single conversion from input buffer to
** output buffer at a fixed conversion ratio.
** Simple interface does not require initialisation as it can only operate on
** a single buffer worth of audio.
*}
function src_simple(data: PSRC_DATA; converter_type: cint; channels: cint): cint; cdecl; external LibName;
{*
** This library contains a number of different sample rate converters,
** numbered 0 through N.
**
** Return a string giving either a name or a more full description of each
** sample rate converter or NULL if no sample rate converter exists for
** the given value. The converters are sequentially numbered from 0 to N.
*}
function src_get_name(converter_type: cint): {const} Pchar; cdecl; external LibName;
function src_get_description(converter_type: cint): {const} Pchar; cdecl; external LibName;
function src_get_version(): {const} Pchar; cdecl; external LibName;
{*
** Set a new SRC ratio. This allows step responses
** in the conversion ratio.
** Returns non zero on error.
*}
function src_set_ratio(state: PSRC_STATE; new_ratio: cdouble): cint; cdecl; external LibName;
{*
** Reset the internal SRC state.
** Does not modify the quality settings.
** Does not free any memory allocations.
** Returns non zero on error.
*}
function src_reset(state: PSRC_STATE): cint; cdecl; external LibName;
{*
** Return TRUE if ratio is a valid conversion ratio, FALSE
** otherwise.
*}
function src_is_valid_ratio(ratio: cdouble): cint; cdecl; external LibName;
{*
** Return an error number.
*}
function src_error(state: PSRC_STATE): cint; cdecl; external LibName;
{*
** Convert the error number into a string.
*}
function src_strerror(error: cint): {const} Pchar; cdecl; external LibName;
{*
** The following enums can be used to set the interpolator type
** using the function src_set_converter().
*}
const
SRC_SINC_BEST_QUALITY = 0;
SRC_SINC_MEDIUM_QUALITY = 1;
SRC_SINC_FASTEST = 2;
SRC_ZERO_ORDER_HOLD = 3;
SRC_LINEAR = 4;
{*
** Extra helper functions for converting from short to float and
** back again.
*}
procedure src_short_to_float_array(input: {const} PCshort; output: PCfloat; len: cint); cdecl; external LibName;
procedure src_float_to_short_array(input: {const} PCfloat; output: PCshort; len: cint); cdecl; external LibName;
{$IF LIBSAMPLERATE_VERSION >= 1003} // 0.1.3
procedure src_int_to_float_array(input: {const} PCint; output: PCfloat; len: cint); cdecl; external LibName;
procedure src_float_to_int_array(input: {const} PCfloat; output: PCint; len: cint); cdecl; external LibName;
{$IFEND}
implementation
end.
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