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| 1 /* Copyright (C) Jean-Marc Valin */ |
| 2 /** |
| 3 @file speex_echo.h |
| 4 @brief Echo cancellation |
| 5 */ |
| 6 /* |
| 7 Redistribution and use in source and binary forms, with or without |
| 8 modification, are permitted provided that the following conditions are |
| 9 met: |
| 10 |
| 11 1. Redistributions of source code must retain the above copyright notice, |
| 12 this list of conditions and the following disclaimer. |
| 13 |
| 14 2. Redistributions in binary form must reproduce the above copyright |
| 15 notice, this list of conditions and the following disclaimer in the |
| 16 documentation and/or other materials provided with the distribution. |
| 17 |
| 18 3. The name of the author may not be used to endorse or promote products |
| 19 derived from this software without specific prior written permission. |
| 20 |
| 21 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 22 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 23 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| 24 DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, |
| 25 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 26 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 27 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 29 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| 30 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 31 POSSIBILITY OF SUCH DAMAGE. |
| 32 */ |
| 33 |
| 34 #ifndef SPEEX_ECHO_H |
| 35 #define SPEEX_ECHO_H |
| 36 /** @defgroup SpeexEchoState SpeexEchoState: Acoustic echo canceller |
| 37 * This is the acoustic echo canceller module. |
| 38 * @{ |
| 39 */ |
| 40 #include "speex/speex_types.h" |
| 41 |
| 42 #ifdef __cplusplus |
| 43 extern "C" { |
| 44 #endif |
| 45 |
| 46 /** Obtain frame size used by the AEC */ |
| 47 #define SPEEX_ECHO_GET_FRAME_SIZE 3 |
| 48 |
| 49 /** Set sampling rate */ |
| 50 #define SPEEX_ECHO_SET_SAMPLING_RATE 24 |
| 51 /** Get sampling rate */ |
| 52 #define SPEEX_ECHO_GET_SAMPLING_RATE 25 |
| 53 |
| 54 /* Can't set window sizes */ |
| 55 /** Get size of impulse response (int32) */ |
| 56 #define SPEEX_ECHO_GET_IMPULSE_RESPONSE_SIZE 27 |
| 57 |
| 58 /* Can't set window content */ |
| 59 /** Get impulse response (int32[]) */ |
| 60 #define SPEEX_ECHO_GET_IMPULSE_RESPONSE 29 |
| 61 |
| 62 /** Internal echo canceller state. Should never be accessed directly. */ |
| 63 struct SpeexEchoState_; |
| 64 |
| 65 /** @class SpeexEchoState |
| 66 * This holds the state of the echo canceller. You need one per channel. |
| 67 */ |
| 68 |
| 69 /** Internal echo canceller state. Should never be accessed directly. */ |
| 70 typedef struct SpeexEchoState_ SpeexEchoState; |
| 71 |
| 72 /** Creates a new echo canceller state |
| 73 * @param frame_size Number of samples to process at one time (should correspond
to 10-20 ms) |
| 74 * @param filter_length Number of samples of echo to cancel (should generally co
rrespond to 100-500 ms) |
| 75 * @return Newly-created echo canceller state |
| 76 */ |
| 77 SpeexEchoState *speex_echo_state_init(int frame_size, int filter_length); |
| 78 |
| 79 /** Creates a new multi-channel echo canceller state |
| 80 * @param frame_size Number of samples to process at one time (should correspond
to 10-20 ms) |
| 81 * @param filter_length Number of samples of echo to cancel (should generally co
rrespond to 100-500 ms) |
| 82 * @param nb_mic Number of microphone channels |
| 83 * @param nb_speakers Number of speaker channels |
| 84 * @return Newly-created echo canceller state |
| 85 */ |
| 86 SpeexEchoState *speex_echo_state_init_mc(int frame_size, int filter_length, int
nb_mic, int nb_speakers); |
| 87 |
| 88 /** Destroys an echo canceller state |
| 89 * @param st Echo canceller state |
| 90 */ |
| 91 void speex_echo_state_destroy(SpeexEchoState *st); |
| 92 |
| 93 /** Performs echo cancellation a frame, based on the audio sent to the speaker (
no delay is added |
| 94 * to playback in this form) |
| 95 * |
| 96 * @param st Echo canceller state |
| 97 * @param rec Signal from the microphone (near end + far end echo) |
| 98 * @param play Signal played to the speaker (received from far end) |
| 99 * @param out Returns near-end signal with echo removed |
| 100 */ |
| 101 void speex_echo_cancellation(SpeexEchoState *st, const spx_int16_t *rec, const s
px_int16_t *play, spx_int16_t *out); |
| 102 |
| 103 /** Performs echo cancellation a frame (deprecated) */ |
| 104 void speex_echo_cancel(SpeexEchoState *st, const spx_int16_t *rec, const spx_int
16_t *play, spx_int16_t *out, spx_int32_t *Yout); |
| 105 |
| 106 /** Perform echo cancellation using internal playback buffer, which is delayed b
y two frames |
| 107 * to account for the delay introduced by most soundcards (but it could be off!) |
| 108 * @param st Echo canceller state |
| 109 * @param rec Signal from the microphone (near end + far end echo) |
| 110 * @param out Returns near-end signal with echo removed |
| 111 */ |
| 112 void speex_echo_capture(SpeexEchoState *st, const spx_int16_t *rec, spx_int16_t
*out); |
| 113 |
| 114 /** Let the echo canceller know that a frame was just queued to the soundcard |
| 115 * @param st Echo canceller state |
| 116 * @param play Signal played to the speaker (received from far end) |
| 117 */ |
| 118 void speex_echo_playback(SpeexEchoState *st, const spx_int16_t *play); |
| 119 |
| 120 /** Reset the echo canceller to its original state |
| 121 * @param st Echo canceller state |
| 122 */ |
| 123 void speex_echo_state_reset(SpeexEchoState *st); |
| 124 |
| 125 /** Used like the ioctl function to control the echo canceller parameters |
| 126 * |
| 127 * @param st Echo canceller state |
| 128 * @param request ioctl-type request (one of the SPEEX_ECHO_* macros) |
| 129 * @param ptr Data exchanged to-from function |
| 130 * @return 0 if no error, -1 if request in unknown |
| 131 */ |
| 132 int speex_echo_ctl(SpeexEchoState *st, int request, void *ptr); |
| 133 |
| 134 |
| 135 |
| 136 struct SpeexDecorrState_; |
| 137 |
| 138 typedef struct SpeexDecorrState_ SpeexDecorrState; |
| 139 |
| 140 |
| 141 /** Create a state for the channel decorrelation algorithm |
| 142 This is useful for multi-channel echo cancellation only |
| 143 * @param rate Sampling rate |
| 144 * @param channels Number of channels (it's a bit pointless if you don't have at
least 2) |
| 145 * @param frame_size Size of the frame to process at ones (counting samples *per
* channel) |
| 146 */ |
| 147 SpeexDecorrState *speex_decorrelate_new(int rate, int channels, int frame_size); |
| 148 |
| 149 /** Remove correlation between the channels by modifying the phase and possibly |
| 150 adding noise in a way that is not (or little) perceptible. |
| 151 * @param st Decorrelator state |
| 152 * @param in Input audio in interleaved format |
| 153 * @param out Result of the decorrelation (out *may* alias in) |
| 154 * @param strength How much alteration of the audio to apply from 0 to 100. |
| 155 */ |
| 156 void speex_decorrelate(SpeexDecorrState *st, const spx_int16_t *in, spx_int16_t
*out, int strength); |
| 157 |
| 158 /** Destroy a Decorrelation state |
| 159 * @param st State to destroy |
| 160 */ |
| 161 void speex_decorrelate_destroy(SpeexDecorrState *st); |
| 162 |
| 163 |
| 164 #ifdef __cplusplus |
| 165 } |
| 166 #endif |
| 167 |
| 168 |
| 169 /** @}*/ |
| 170 #endif |
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