{* ** 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; {$IFDEF FPC} {$IFNDEF win32} {$LINKLIB libsamplerate} {$ENDIF} {$PACKRECORDS C} (* GCC/Visual C/C++ compatible record packing *) {$MODE DELPHI} {$ENDIF} interface const {$IFDEF WIN32} LibName = 'libsamplerate.dll'; {$ENDIF} {$IFDEF LINUX} LibName = 'samplerate'; {$ENDIF} {$IFDEF MACOS} {LibName = 'unknown';} {$ENDIF} { Opaque data type SRC_STATE. } type PSRC_STATE = ^SRC_STATE; SRC_STATE = record end; { SRC_DATA is used to pass data to src_simple() and src_process(). } type PSRC_DATA = ^SRC_DATA; SRC_DATA = record data_in: Pdouble; data_out: Pdouble; input_frames: longint; output_frames: longint; input_frames_used: longint; output_frames_gen: longint; end_of_input: integer; src_ratio: double; end; { SRC_CB_DATA is used with callback based API. } type SRC_CB_DATA = record frames: longint; data_in: Psingle; end; type PPsingle = ^Psingle; {* ** 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; data: PPsingle): longint; 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: integer; channels: integer; error: Pinteger): 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: integer; channels: integer; 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): integer; 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: double; frames: longint; data: Psingle): longint; 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: integer; channels: integer): integer; 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. *} (* Const before type ignored *) function src_get_name(converter_type: integer): Pchar; cdecl; external LibName; (* Const before type ignored *) function src_get_description(converter_type: integer): Pchar; cdecl; external LibName; (* Const before type ignored *) function src_get_version(): 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: double): integer; 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): integer; cdecl; external LibName; {* ** Return TRUE if ratio is a valid conversion ratio, FALSE ** otherwise. *} function src_is_valid_ratio(ratio: double): integer; cdecl; external LibName; {* ** Return an error number. *} function src_error(state: PSRC_STATE): integer; cdecl; external LibName; {* ** Convert the error number into a string. *} (* Const before type ignored *) function src_strerror(error: integer): Pchar; cdecl; external LibName; {* ** The following enums can be used to set the interpolator type ** using the function src_set_converter(). *} type TConverterType = {enum}integer; const {enum_begin TConverterType} SRC_SINC_BEST_QUALITY = 0; SRC_SINC_MEDIUM_QUALITY = 1; SRC_SINC_FASTEST = 2; SRC_ZERO_ORDER_HOLD = 3; SRC_LINEAR = 4; {enum_end TConverterType} {* ** Extra helper functions for converting from short to float and ** back again. *} (* Const before type ignored *) procedure src_short_to_float_array(input: Psmallint; output: Psingle; len: integer); cdecl; external LibName; (* Const before type ignored *) procedure src_float_to_short_array(input: Psingle; output: Psmallint; len: integer); cdecl; external LibName; implementation end.