| /* Copyright (C) Jean-Marc Valin */ |
| /** |
| @file speex_echo.h |
| @brief Echo cancellation |
| */ |
| /* |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are |
| met: |
| |
| 1. Redistributions of source code must retain the above copyright notice, |
| this list of conditions and the following disclaimer. |
| |
| 2. Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| |
| 3. The name of the author may not be used to endorse or promote products |
| derived from this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, |
| INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #ifndef SPEEX_ECHO_H |
| #define SPEEX_ECHO_H |
| /** @defgroup SpeexEchoState SpeexEchoState: Acoustic echo canceller |
| * This is the acoustic echo canceller module. |
| * @{ |
| */ |
| #include "speex/speex_types.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** Obtain frame size used by the AEC */ |
| #define SPEEX_ECHO_GET_FRAME_SIZE 3 |
| |
| /** Set sampling rate */ |
| #define SPEEX_ECHO_SET_SAMPLING_RATE 24 |
| /** Get sampling rate */ |
| #define SPEEX_ECHO_GET_SAMPLING_RATE 25 |
| |
| /* Can't set window sizes */ |
| /** Get size of impulse response (int32) */ |
| #define SPEEX_ECHO_GET_IMPULSE_RESPONSE_SIZE 27 |
| |
| /* Can't set window content */ |
| /** Get impulse response (int32[]) */ |
| #define SPEEX_ECHO_GET_IMPULSE_RESPONSE 29 |
| |
| /** Internal echo canceller state. Should never be accessed directly. */ |
| struct SpeexEchoState_; |
| |
| /** @class SpeexEchoState |
| * This holds the state of the echo canceller. You need one per channel. |
| */ |
| |
| /** Internal echo canceller state. Should never be accessed directly. */ |
| typedef struct SpeexEchoState_ SpeexEchoState; |
| |
| /** Creates a new echo canceller state |
| * @param frame_size Number of samples to process at one time (should correspond to 10-20 ms) |
| * @param filter_length Number of samples of echo to cancel (should generally correspond to 100-500 ms) |
| * @return Newly-created echo canceller state |
| */ |
| SpeexEchoState *speex_echo_state_init(int frame_size, int filter_length); |
| |
| /** Creates a new multi-channel echo canceller state |
| * @param frame_size Number of samples to process at one time (should correspond to 10-20 ms) |
| * @param filter_length Number of samples of echo to cancel (should generally correspond to 100-500 ms) |
| * @param nb_mic Number of microphone channels |
| * @param nb_speakers Number of speaker channels |
| * @return Newly-created echo canceller state |
| */ |
| SpeexEchoState *speex_echo_state_init_mc(int frame_size, int filter_length, int nb_mic, int nb_speakers); |
| |
| /** Destroys an echo canceller state |
| * @param st Echo canceller state |
| */ |
| void speex_echo_state_destroy(SpeexEchoState *st); |
| |
| /** Performs echo cancellation a frame, based on the audio sent to the speaker (no delay is added |
| * to playback in this form) |
| * |
| * @param st Echo canceller state |
| * @param rec Signal from the microphone (near end + far end echo) |
| * @param play Signal played to the speaker (received from far end) |
| * @param out Returns near-end signal with echo removed |
| */ |
| void speex_echo_cancellation(SpeexEchoState *st, const spx_int16_t *rec, const spx_int16_t *play, spx_int16_t *out); |
| |
| /** Performs echo cancellation a frame (deprecated) */ |
| void speex_echo_cancel(SpeexEchoState *st, const spx_int16_t *rec, const spx_int16_t *play, spx_int16_t *out, spx_int32_t *Yout); |
| |
| /** Perform echo cancellation using internal playback buffer, which is delayed by two frames |
| * to account for the delay introduced by most soundcards (but it could be off!) |
| * @param st Echo canceller state |
| * @param rec Signal from the microphone (near end + far end echo) |
| * @param out Returns near-end signal with echo removed |
| */ |
| void speex_echo_capture(SpeexEchoState *st, const spx_int16_t *rec, spx_int16_t *out); |
| |
| /** Let the echo canceller know that a frame was just queued to the soundcard |
| * @param st Echo canceller state |
| * @param play Signal played to the speaker (received from far end) |
| */ |
| void speex_echo_playback(SpeexEchoState *st, const spx_int16_t *play); |
| |
| /** Reset the echo canceller to its original state |
| * @param st Echo canceller state |
| */ |
| void speex_echo_state_reset(SpeexEchoState *st); |
| |
| /** Used like the ioctl function to control the echo canceller parameters |
| * |
| * @param st Echo canceller state |
| * @param request ioctl-type request (one of the SPEEX_ECHO_* macros) |
| * @param ptr Data exchanged to-from function |
| * @return 0 if no error, -1 if request in unknown |
| */ |
| int speex_echo_ctl(SpeexEchoState *st, int request, void *ptr); |
| |
| |
| |
| struct SpeexDecorrState_; |
| |
| typedef struct SpeexDecorrState_ SpeexDecorrState; |
| |
| |
| /** Create a state for the channel decorrelation algorithm |
| This is useful for multi-channel echo cancellation only |
| * @param rate Sampling rate |
| * @param channels Number of channels (it's a bit pointless if you don't have at least 2) |
| * @param frame_size Size of the frame to process at ones (counting samples *per* channel) |
| */ |
| SpeexDecorrState *speex_decorrelate_new(int rate, int channels, int frame_size); |
| |
| /** Remove correlation between the channels by modifying the phase and possibly |
| adding noise in a way that is not (or little) perceptible. |
| * @param st Decorrelator state |
| * @param in Input audio in interleaved format |
| * @param out Result of the decorrelation (out *may* alias in) |
| * @param strength How much alteration of the audio to apply from 0 to 100. |
| */ |
| void speex_decorrelate(SpeexDecorrState *st, const spx_int16_t *in, spx_int16_t *out, int strength); |
| |
| /** Destroy a Decorrelation state |
| * @param st State to destroy |
| */ |
| void speex_decorrelate_destroy(SpeexDecorrState *st); |
| |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| |
| /** @}*/ |
| #endif |