Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 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 correspond 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 correspond 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 spx_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_int16_t *play, spx_int16_t *out, spx_int32_t *Yout); |
| 105 | |
| 106 | /** Perform echo cancellation using internal playback buffer, which is delayed by 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 |