Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [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_STEREO_H__ |
| 21 | #define __PJMEDIA_STEREO_H__ |
| 22 | |
| 23 | /** |
| 24 | * @file stereo.h |
| 25 | * @brief Monochannel and multichannel converter. |
| 26 | */ |
| 27 | |
| 28 | #include <pjmedia/errno.h> |
| 29 | #include <pjmedia/port.h> |
| 30 | #include <pjmedia/types.h> |
| 31 | #include <pj/assert.h> |
| 32 | |
| 33 | |
| 34 | /** |
| 35 | * @defgroup PJMEDIA_STEREO Monochannel and multichannel audio frame converter |
| 36 | * @ingroup PJMEDIA_FRAME_OP |
| 37 | * @brief Mono - multi-channels audio conversion |
| 38 | * @{ |
| 39 | * |
| 40 | */ |
| 41 | |
| 42 | PJ_BEGIN_DECL |
| 43 | |
| 44 | |
| 45 | /** |
| 46 | * Multichannel to monochannel conversion mixes samples from all channels |
| 47 | * into the monochannel. |
| 48 | */ |
| 49 | #define PJMEDIA_STEREO_MIX PJ_TRUE |
| 50 | |
| 51 | |
| 52 | |
| 53 | /** |
| 54 | * Multichannel to monochannel conversion, it has two operation mode specified |
| 55 | * by param options, @see pjmedia_stereo_options. This function can work safely |
| 56 | * using the same buffer (in place conversion). |
| 57 | * |
| 58 | * @param mono Output buffer to store the mono frame extracted |
| 59 | * from the multichannels frame. |
| 60 | * @param multi Input frame containing multichannels audio. |
| 61 | * @param channel_count Number of channels in the input frame. |
| 62 | * @param samples_per_frame Number of samples in the input frame. |
| 63 | * @param mix If the value is PJ_TRUE then the input channels |
| 64 | * will be mixed to produce output frame, otherwise |
| 65 | * only frame from channel_src will be copied to the |
| 66 | * output frame. |
| 67 | * @param channel_src When mixing is disabled, the mono output frame |
| 68 | * will be copied from this channel number. |
| 69 | * |
| 70 | * @return PJ_SUCCESS on success; |
| 71 | */ |
| 72 | PJ_INLINE(pj_status_t) pjmedia_convert_channel_nto1(pj_int16_t mono[], |
| 73 | const pj_int16_t multi[], |
| 74 | unsigned channel_count, |
| 75 | unsigned samples_per_frame, |
| 76 | pj_bool_t mix, |
| 77 | unsigned channel_src) |
| 78 | { |
| 79 | unsigned i; |
| 80 | |
| 81 | PJ_ASSERT_RETURN(mono && multi && channel_count && samples_per_frame && |
| 82 | channel_src < channel_count, PJ_EINVAL); |
| 83 | |
| 84 | if (mix==PJ_FALSE) { |
| 85 | for (i = channel_src; i < samples_per_frame; i += channel_count) { |
| 86 | *mono = multi[i]; |
| 87 | ++mono; |
| 88 | } |
| 89 | } else { |
| 90 | unsigned j; |
| 91 | for (i = 0; i < samples_per_frame; i += channel_count) { |
| 92 | int tmp = 0; |
| 93 | for(j = 0; j < channel_count; ++j) |
| 94 | tmp += multi[i+j]; |
| 95 | |
| 96 | if (tmp > 32767) tmp = 32767; |
| 97 | else if (tmp < -32768) tmp = -32768; |
| 98 | *mono = (pj_int16_t) tmp; |
| 99 | ++mono; |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | return PJ_SUCCESS; |
| 104 | } |
| 105 | |
| 106 | |
| 107 | /** |
| 108 | * Monochannel to multichannel conversion, it will just duplicate the samples |
| 109 | * from monochannel frame to all channels in the multichannel frame. |
| 110 | * This function can work safely using the same buffer (in place conversion) |
| 111 | * as long as the buffer is big enough for the multichannel samples. |
| 112 | * |
| 113 | * @param multi Output buffer to store the multichannels frame |
| 114 | * mixed from the mono frame. |
| 115 | * @param mono The input monochannel audio frame. |
| 116 | * @param channel_count Desired number of channels in the output frame. |
| 117 | * @param samples_per_frame Number of samples in the input frame. |
| 118 | * @param options Options for conversion, currently must be zero. |
| 119 | * |
| 120 | * @return PJ_SUCCESS on success; |
| 121 | */ |
| 122 | PJ_INLINE(pj_status_t) pjmedia_convert_channel_1ton(pj_int16_t multi[], |
| 123 | const pj_int16_t mono[], |
| 124 | unsigned channel_count, |
| 125 | unsigned samples_per_frame, |
| 126 | unsigned options) |
| 127 | { |
| 128 | const pj_int16_t *src; |
| 129 | |
| 130 | PJ_ASSERT_RETURN(mono && multi && channel_count && samples_per_frame, |
| 131 | PJ_EINVAL); |
| 132 | PJ_ASSERT_RETURN(options == 0, PJ_EINVAL); |
| 133 | |
| 134 | PJ_UNUSED_ARG(options); |
| 135 | |
| 136 | src = mono + samples_per_frame - 1; |
| 137 | samples_per_frame *= channel_count; |
| 138 | while (samples_per_frame) { |
| 139 | unsigned i; |
| 140 | for (i=1; i<=channel_count; ++i) |
| 141 | multi[samples_per_frame-i] = *src; |
| 142 | samples_per_frame -= channel_count; |
| 143 | --src; |
| 144 | } |
| 145 | |
| 146 | return PJ_SUCCESS; |
| 147 | } |
| 148 | |
| 149 | |
| 150 | /** |
| 151 | * Options for channel converter port. The #pjmedia_stereo_options is also |
| 152 | * valid for this port options. |
| 153 | */ |
| 154 | typedef enum pjmedia_stereo_port_options |
| 155 | { |
| 156 | /** |
| 157 | * Specifies whether this port should not destroy downstream port when |
| 158 | * this port is destroyed. |
| 159 | */ |
| 160 | PJMEDIA_STEREO_DONT_DESTROY_DN = 4 |
| 161 | } pjmedia_stereo_port_options; |
| 162 | |
| 163 | |
| 164 | /** |
| 165 | * Create a mono-multi channel converter port. This creates a converter session, |
| 166 | * which will adjust the samples of audio frame to a different channel count |
| 167 | * when the port's get_frame() and put_frame() is called. |
| 168 | * |
| 169 | * When the port's get_frame() is called, this port will get a frame from |
| 170 | * the downstream port and convert the frame to the target channel count before |
| 171 | * returning it to the caller. |
| 172 | * |
| 173 | * When the port's put_frame() is called, this port will convert the frame |
| 174 | * to the downstream port's channel count before giving the frame to the |
| 175 | * downstream port. |
| 176 | * |
| 177 | * @param pool Pool to allocate the structure and buffers. |
| 178 | * @param dn_port The downstream port, which channel count is to |
| 179 | * be converted to the target channel count. |
| 180 | * @param channel_count This port channel count. |
| 181 | * @param options Bitmask flags from #pjmedia_stereo_port_options |
| 182 | * and also application may add PJMEDIA_STEREO_MIX |
| 183 | * to mix channels. |
| 184 | * When this flag is zero, the default behavior |
| 185 | * is to use simple N-to-1 channel converter and |
| 186 | * to destroy downstream port when this port is |
| 187 | * destroyed. |
| 188 | * @param p_port Pointer to receive the stereo port instance. |
| 189 | * |
| 190 | * @return PJ_SUCCESS on success. |
| 191 | */ |
| 192 | PJ_DECL(pj_status_t) pjmedia_stereo_port_create( pj_pool_t *pool, |
| 193 | pjmedia_port *dn_port, |
| 194 | unsigned channel_count, |
| 195 | unsigned options, |
| 196 | pjmedia_port **p_port ); |
| 197 | |
| 198 | PJ_END_DECL |
| 199 | |
| 200 | /** |
| 201 | * @} |
| 202 | */ |
| 203 | |
| 204 | |
| 205 | #endif /* __PJMEDIA_STEREO_H__ */ |
| 206 | |