SpeexEchoState: Acoustic echo canceller
Classes |
class | SpeexEchoState |
Defines |
#define | SPEEX_ECHO_GET_FRAME_SIZE 3 |
#define | SPEEX_ECHO_SET_SAMPLING_RATE 24 |
#define | SPEEX_ECHO_GET_SAMPLING_RATE 25 |
#define | SPEEX_ECHO_GET_IMPULSE_RESPONSE_SIZE 27 |
#define | SPEEX_ECHO_GET_IMPULSE_RESPONSE 29 |
Typedefs |
typedef struct SpeexEchoState_ | SpeexEchoState |
typedef struct SpeexDecorrState_ | SpeexDecorrState |
Functions |
SpeexEchoState * | speex_echo_state_init (int frame_size, int filter_length) |
SpeexEchoState * | speex_echo_state_init_mc (int frame_size, int filter_length, int nb_mic, int nb_speakers) |
void | speex_echo_state_destroy (SpeexEchoState *st) |
void | speex_echo_cancellation (SpeexEchoState *st, const spx_int16_t *rec, const spx_int16_t *play, spx_int16_t *out) |
void | speex_echo_cancel (SpeexEchoState *st, const spx_int16_t *rec, const spx_int16_t *play, spx_int16_t *out, spx_int32_t *Yout) |
void | speex_echo_capture (SpeexEchoState *st, const spx_int16_t *rec, spx_int16_t *out) |
void | speex_echo_playback (SpeexEchoState *st, const spx_int16_t *play) |
void | speex_echo_state_reset (SpeexEchoState *st) |
int | speex_echo_ctl (SpeexEchoState *st, int request, void *ptr) |
SpeexDecorrState * | speex_decorrelate_new (int rate, int channels, int frame_size) |
void | speex_decorrelate (SpeexDecorrState *st, const spx_int16_t *in, spx_int16_t *out, int strength) |
void | speex_decorrelate_destroy (SpeexDecorrState *st) |
Detailed Description
This is the acoustic echo canceller module.
Define Documentation
#define SPEEX_ECHO_GET_FRAME_SIZE 3 |
Obtain frame size used by the AEC
#define SPEEX_ECHO_GET_IMPULSE_RESPONSE 29 |
Get impulse response (int32[])
#define SPEEX_ECHO_GET_IMPULSE_RESPONSE_SIZE 27 |
Get size of impulse response (int32)
#define SPEEX_ECHO_GET_SAMPLING_RATE 25 |
#define SPEEX_ECHO_SET_SAMPLING_RATE 24 |
Typedef Documentation
Internal echo canceller state. Should never be accessed directly.
Function Documentation
void speex_decorrelate |
( |
SpeexDecorrState * |
st, |
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const spx_int16_t * |
in, |
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spx_int16_t * |
out, |
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int |
strength | |
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) |
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Remove correlation between the channels by modifying the phase and possibly adding noise in a way that is not (or little) perceptible.
- Parameters:
-
| st | Decorrelator state |
| in | Input audio in interleaved format |
| out | Result of the decorrelation (out *may* alias in) |
| strength | How much alteration of the audio to apply from 0 to 100. |
void speex_decorrelate_destroy |
( |
SpeexDecorrState * |
st |
) |
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Destroy a Decorrelation state
- Parameters:
-
SpeexDecorrState* speex_decorrelate_new |
( |
int |
rate, |
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int |
channels, |
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int |
frame_size | |
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) |
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Create a state for the channel decorrelation algorithm This is useful for multi-channel echo cancellation only
- Parameters:
-
| rate | Sampling rate |
| channels | Number of channels (it's a bit pointless if you don't have at least 2) |
| frame_size | Size of the frame to process at ones (counting samples *per* channel) |
void speex_echo_cancel |
( |
SpeexEchoState * |
st, |
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const spx_int16_t * |
rec, |
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const spx_int16_t * |
play, |
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spx_int16_t * |
out, |
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spx_int32_t * |
Yout | |
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) |
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Performs echo cancellation a frame (deprecated)
void speex_echo_cancellation |
( |
SpeexEchoState * |
st, |
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const spx_int16_t * |
rec, |
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const spx_int16_t * |
play, |
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spx_int16_t * |
out | |
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) |
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Performs echo cancellation a frame, based on the audio sent to the speaker (no delay is added to playback in this form)
- Parameters:
-
| st | Echo canceller state |
| rec | Signal from the microphone (near end + far end echo) |
| play | Signal played to the speaker (received from far end) |
| out | Returns near-end signal with echo removed |
void speex_echo_capture |
( |
SpeexEchoState * |
st, |
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const spx_int16_t * |
rec, |
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spx_int16_t * |
out | |
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) |
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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!)
- Parameters:
-
| st | Echo canceller state |
| rec | Signal from the microphone (near end + far end echo) |
| out | Returns near-end signal with echo removed |
Used like the ioctl function to control the echo canceller parameters
- Parameters:
-
| st | Echo canceller state |
| request | ioctl-type request (one of the SPEEX_ECHO_* macros) |
| ptr | Data exchanged to-from function |
- Returns:
- 0 if no error, -1 if request in unknown
void speex_echo_playback |
( |
SpeexEchoState * |
st, |
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const spx_int16_t * |
play | |
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) |
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Let the echo canceller know that a frame was just queued to the soundcard
- Parameters:
-
| st | Echo canceller state |
| play | Signal played to the speaker (received from far end) |
Destroys an echo canceller state
- Parameters:
-
SpeexEchoState* speex_echo_state_init |
( |
int |
frame_size, |
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int |
filter_length | |
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) |
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Creates a new echo canceller state
- Parameters:
-
| frame_size | Number of samples to process at one time (should correspond to 10-20 ms) |
| filter_length | Number of samples of echo to cancel (should generally correspond to 100-500 ms) |
- Returns:
- Newly-created echo canceller state
SpeexEchoState* speex_echo_state_init_mc |
( |
int |
frame_size, |
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int |
filter_length, |
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int |
nb_mic, |
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int |
nb_speakers | |
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) |
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Creates a new multi-channel echo canceller state
- Parameters:
-
| frame_size | Number of samples to process at one time (should correspond to 10-20 ms) |
| filter_length | Number of samples of echo to cancel (should generally correspond to 100-500 ms) |
| nb_mic | Number of microphone channels |
| nb_speakers | Number of speaker channels |
- Returns:
- Newly-created echo canceller state
Reset the echo canceller to its original state
- Parameters:
-