Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [diff] [blame] | 1 | /* $Id$ */ |
| 2 | /* |
| 3 | * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| 4 | * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | */ |
| 20 | #ifndef __PJMEDIA_RESAMPLE_H__ |
| 21 | #define __PJMEDIA_RESAMPLE_H__ |
| 22 | |
| 23 | |
| 24 | |
| 25 | /** |
| 26 | * @file resample.h |
| 27 | * @brief Sample rate converter. |
| 28 | */ |
| 29 | #include <pjmedia/types.h> |
| 30 | #include <pjmedia/port.h> |
| 31 | |
| 32 | /** |
| 33 | * @defgroup PJMEDIA_RESAMPLE Resampling Algorithm |
| 34 | * @ingroup PJMEDIA_FRAME_OP |
| 35 | * @brief Sample rate conversion algorithm |
| 36 | * @{ |
| 37 | * |
| 38 | * This section describes the base resampling functions. In addition to this, |
| 39 | * application can use the @ref PJMEDIA_RESAMPLE_PORT which provides |
| 40 | * media port abstraction for the base resampling algorithm. |
| 41 | */ |
| 42 | |
| 43 | PJ_BEGIN_DECL |
| 44 | |
| 45 | /* |
| 46 | * This file declares two types of API: |
| 47 | * |
| 48 | * Application can use #pjmedia_resample_create() and #pjmedia_resample_run() |
| 49 | * to convert a frame from source rate to destination rate. The inpuit frame |
| 50 | * must have a constant length. |
| 51 | * |
| 52 | * Alternatively, application can create a resampling port with |
| 53 | * #pjmedia_resample_port_create() and connect the port to other ports to |
| 54 | * change the sampling rate of the samples. |
| 55 | */ |
| 56 | |
| 57 | |
| 58 | /** |
| 59 | * Opaque resample session. |
| 60 | */ |
| 61 | typedef struct pjmedia_resample pjmedia_resample; |
| 62 | |
| 63 | /** |
| 64 | * Create a frame based resample session. |
| 65 | * |
| 66 | * @param pool Pool to allocate the structure and buffers. |
| 67 | * @param high_quality If true, then high quality conversion will be |
| 68 | * used, at the expense of more CPU and memory, |
| 69 | * because temporary buffer needs to be created. |
| 70 | * @param large_filter If true, large filter size will be used. |
| 71 | * @param channel_count Number of channels. |
| 72 | * @param rate_in Clock rate of the input samples. |
| 73 | * @param rate_out Clock rate of the output samples. |
| 74 | * @param samples_per_frame Number of samples per frame in the input. |
| 75 | * @param p_resample Pointer to receive the resample session. |
| 76 | * |
| 77 | * @return PJ_SUCCESS on success. |
| 78 | */ |
| 79 | PJ_DECL(pj_status_t) pjmedia_resample_create(pj_pool_t *pool, |
| 80 | pj_bool_t high_quality, |
| 81 | pj_bool_t large_filter, |
| 82 | unsigned channel_count, |
| 83 | unsigned rate_in, |
| 84 | unsigned rate_out, |
| 85 | unsigned samples_per_frame, |
| 86 | pjmedia_resample **p_resample); |
| 87 | |
| 88 | |
| 89 | /** |
| 90 | * Use the resample session to resample a frame. The frame must have the |
| 91 | * same size and settings as the resample session, or otherwise the |
| 92 | * behavior is undefined. |
| 93 | * |
| 94 | * @param resample The resample session. |
| 95 | * @param input Buffer containing the input samples. |
| 96 | * @param output Buffer to store the output samples. |
| 97 | */ |
| 98 | PJ_DECL(void) pjmedia_resample_run( pjmedia_resample *resample, |
| 99 | const pj_int16_t *input, |
| 100 | pj_int16_t *output ); |
| 101 | |
| 102 | |
| 103 | /** |
| 104 | * Get the input frame size of a resample session. |
| 105 | * |
| 106 | * @param resample The resample session. |
| 107 | * |
| 108 | * @return The frame size, in number of samples. |
| 109 | */ |
| 110 | PJ_DECL(unsigned) pjmedia_resample_get_input_size(pjmedia_resample *resample); |
| 111 | |
| 112 | |
| 113 | /** |
| 114 | * Destroy the resample. |
| 115 | * |
| 116 | * @param resample The resample session. |
| 117 | */ |
| 118 | PJ_DECL(void) pjmedia_resample_destroy(pjmedia_resample *resample); |
| 119 | |
| 120 | /** |
| 121 | * @} |
| 122 | */ |
| 123 | |
| 124 | /** |
| 125 | * @defgroup PJMEDIA_RESAMPLE_PORT Resample Port |
| 126 | * @ingroup PJMEDIA_PORT |
| 127 | * @brief Audio sample rate conversion |
| 128 | * @{ |
| 129 | * |
| 130 | * This section describes media port abstraction for @ref PJMEDIA_RESAMPLE. |
| 131 | */ |
| 132 | |
| 133 | |
| 134 | /** |
| 135 | * Option flags that can be specified when creating resample port. |
| 136 | */ |
| 137 | enum pjmedia_resample_port_options |
| 138 | { |
| 139 | /** |
| 140 | * Do not use high quality resampling algorithm, but use linear |
| 141 | * algorithm instead. |
| 142 | */ |
| 143 | PJMEDIA_RESAMPLE_USE_LINEAR = 1, |
| 144 | |
| 145 | /** |
| 146 | * Use small filter workspace when high quality resampling is |
| 147 | * used. |
| 148 | */ |
| 149 | PJMEDIA_RESAMPLE_USE_SMALL_FILTER = 2, |
| 150 | |
| 151 | /** |
| 152 | * Do not destroy downstream port when resample port is destroyed. |
| 153 | */ |
| 154 | PJMEDIA_RESAMPLE_DONT_DESTROY_DN = 4 |
| 155 | }; |
| 156 | |
| 157 | |
| 158 | |
| 159 | /** |
| 160 | * Create a resample port. This creates a bidirectional resample session, |
| 161 | * which will resample frames when the port's get_frame() and put_frame() |
| 162 | * is called. |
| 163 | * |
| 164 | * When the resample port's get_frame() is called, this port will get |
| 165 | * a frame from the downstream port and resample the frame to the target |
| 166 | * clock rate before returning it to the caller. |
| 167 | * |
| 168 | * When the resample port's put_frame() is called, this port will resample |
| 169 | * the frame to the downstream port's clock rate before giving the frame |
| 170 | * to the downstream port. |
| 171 | * |
| 172 | * @param pool Pool to allocate the structure and buffers. |
| 173 | * @param dn_port The downstream port, which clock rate is to |
| 174 | * be converted to the target clock rate. |
| 175 | * @param clock_rate Target clock rate. |
| 176 | * @param options Flags from #pjmedia_resample_port_options. |
| 177 | * When this flag is zero, the default behavior |
| 178 | * is to use high quality resampling with |
| 179 | * large filter, and to destroy downstream port |
| 180 | * when resample port is destroyed. |
| 181 | * @param p_port Pointer to receive the resample port instance. |
| 182 | * |
| 183 | * @return PJ_SUCCESS on success. |
| 184 | */ |
| 185 | PJ_DECL(pj_status_t) pjmedia_resample_port_create( pj_pool_t *pool, |
| 186 | pjmedia_port *dn_port, |
| 187 | unsigned clock_rate, |
| 188 | unsigned options, |
| 189 | pjmedia_port **p_port ); |
| 190 | |
| 191 | |
| 192 | PJ_END_DECL |
| 193 | |
| 194 | /** |
| 195 | * @} |
| 196 | */ |
| 197 | |
| 198 | |
| 199 | #endif /* __PJMEDIA_RESAMPLE_H__ */ |
| 200 | |