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# lib_ic API State Structure

group ic_state

  Enums

  enum adaption_config_e

    Values:

    enumerator IC_ADAPTION_AUTO
    enumerator IC_ADAPTION_FORCE_ON
    enumerator IC_ADAPTION_FORCE_OFF
  enum control_flag_e

    Values:

    enumerator HOLD
    enumerator ADAPT
    enumerator ADAPT_SLOW
    enumerator UNSTABLE
    enumerator FORCE_ADAPT
    enumerator FORCE_HOLD
  struct ic_config_params_t
    #include <ic_state.h>

    IC configuration structure.

    This structure contains configuration settings that can be changed to alter the behaviour of the IC instance. An instance of this structure is is automatically included as part of the IC state.

    It controls the behaviour of the main filter and normalisation thereof. The initial values for these configuration parameters are defined in ic_defines.h and are initialised by ic_init().

    Public Members

    uint8_t bypass

      Boolean to control bypassing of filter stage and adaption stage. When set the delayed y audio samples are passed unprocessed to the output. It is recommended to perform an initialisation of the instance after bypass is set as the room transfer function may have changed during that time.

    int32_t gamma_log2

      Up scaling factor for X energy calculation used for normalisation.

    uint32_t sigma_xx_shift

      Down scaling factor for X energy for used for normalisation.

    q2_30 ema_alpha_q30

      Alpha used for calculating error_ema_energy in adapt.

    float_s32_t delta

      Delta value used in denominator to avoid large values when calculating inverse X energy.

  struct ic_adaption_controller_config_t
    #include <ic_state.h>

    IC adaption controller configuration structure.

    This structure contains configuration settings that can be changed to alter the behaviour of the adaption controller. This includes processing of the raw VNR probability input and optional stability controller logic. It is automatically included as part of the IC state and initialised by ic_init().

    The initial values for these configuration parameters are defined in ic_defines.h.

    Public Members

    q2_30 energy_alpha_q30

      Alpha for EMA input/output energy calculation.

    float_s32_t fast_ratio_threshold

      Fast ratio threshold to detect instability.

    float_s32_t high_input_vnr_hold_leakage_alpha

      Setting of H_hat leakage which gets set if vnr detects high voice probability.

    float_s32_t instability_recovery_leakage_alpha

      Setting of H_hat leakage which gets set if fast ratio exceeds a threshold.

    float_s32_t input_vnr_threshold

      VNR input threshold which decides whether to hold or adapt the filter.

    float_s32_t input_vnr_threshold_high

      VNR high threshold to leak the filter is the speech level is high.

    float_s32_t input_vnr_threshold_low

      VNR low threshold to adapt faster when the speech level is low.

    uint32_t adapt_counter_limit

      Limits number of frames for which mu and leakage_alpha could be adapted.

    uint8_t enable_adaption

      Boolean which controls whether the IC adapts when ic_adapt() is called.

    adaption_config_e adaption_config

      Enum which controls the way mu and leakage_alpha are being adjusted.

  struct ic_adaption_controller_state_t
    #include <ic_state.h>

    IC adaption controller state structure.

    This structure contains state used for the instance of the adaption controller logic. It is automatically included as part of the IC state and initialised by ic_init().

    Public Members

    float_s32_t input_energy

      EMWA of input frame energy.

    float_s32_t output_energy

      EMWA of output frame energy.

    float_s32_t fast_ratio

      Ratio between output and input EMWA energies.

    uint32_t adapt_counter

      Adaption counter which counts number of frames has been adapted.

    control_flag_e control_flag

      Flag that represents the state of the filter.

    ic_adaption_controller_config_t adaption_controller_config

      Configuration parameters for the adaption controller.

  struct ic_state_t
    #include <ic_state.h>

    IC state structure.

    This is the main state structure for an instance of the Interference Canceller. Before use it must be initialised using the ic_init() function. It contains everything needed for the IC instance including configuration and internal state of both the filter, adaption logic and adaption controller.

    Public Members

    bfp_s32_t y_bfp[IC_Y_CHANNELS]

      BFP array pointing to the time domain y input signal.

    bfp_complex_s32_t Y_bfp[IC_Y_CHANNELS]

      BFP array pointing to the frequency domain Y input signal.

    int32_t y[IC_Y_CHANNELS][IC_FRAME_LENGTH + FFT_PADDING]

      Storage for y and Y mantissas. Note FFT is done in-place so the y storage is reused for Y.

    bfp_s32_t x_bfp[IC_X_CHANNELS]

      BFP array pointing to the time domain x input signal.

    bfp_complex_s32_t X_bfp[IC_X_CHANNELS]

      BFP array pointing to the frequency domain X input signal.

    int32_t x[IC_X_CHANNELS][IC_FRAME_LENGTH + FFT_PADDING]

      Storage for x and X mantissas. Note FFT is done in-place so the x storage is reused for X.

    bfp_s32_t prev_y_bfp[IC_Y_CHANNELS]

      BFP array pointing to previous y samples which are used for framing.

    int32_t y_prev_samples[IC_Y_CHANNELS][IC_FRAME_LENGTH - IC_FRAME_ADVANCE]

      Storage for previous y mantissas.

    bfp_s32_t prev_x_bfp[IC_X_CHANNELS]

      BFP array pointing to previous x samples which are used for framing.

    int32_t x_prev_samples[IC_X_CHANNELS][IC_FRAME_LENGTH - IC_FRAME_ADVANCE]

      Storage for previous x mantissas.

    bfp_complex_s32_t Y_hat_bfp[IC_Y_CHANNELS]

      BFP array pointing to the estimated frequency domain Y signal.

    complex_s32_t Y_hat[IC_Y_CHANNELS][IC_FD_FRAME_LENGTH]

      Storage for Y_hat mantissas.

    bfp_complex_s32_t Error_bfp[IC_Y_CHANNELS]

      BFP array pointing to the frequency domain Error output.

    bfp_s32_t error_bfp[IC_Y_CHANNELS]

      BFP array pointing to the time domain Error output.

    complex_s32_t Error[IC_Y_CHANNELS][IC_FD_FRAME_LENGTH]

      Storage for Error and error mantissas. Note IFFT is done in-place so the Error storage is reused for error.

    bfp_complex_s32_t H_hat_bfp[IC_Y_CHANNELS][IC_X_CHANNELS * IC_FILTER_PHASES]

      BFP array pointing to the frequency domain estimate of transfer function.

    complex_s32_t H_hat[IC_Y_CHANNELS][IC_FILTER_PHASES * IC_X_CHANNELS][IC_FD_FRAME_LENGTH]

      Storage for H_hat mantissas.

    bfp_complex_s32_t X_fifo_bfp[IC_X_CHANNELS][IC_FILTER_PHASES]

      BFP array pointing to the frequency domain X input history used for calculating normalisation.

    bfp_complex_s32_t X_fifo_1d_bfp[IC_X_CHANNELS * IC_FILTER_PHASES]

      1D alias of the frequency domain X input history used for calculating normalisation.

    complex_s32_t X_fifo[IC_X_CHANNELS][IC_FILTER_PHASES][IC_FD_FRAME_LENGTH]

      Storage for X_fifo mantissas.

    bfp_complex_s32_t T_bfp[IC_X_CHANNELS]

      BFP array pointing to the frequency domain T used for adapting the filter coefficients (H). Note there is no associated storage because we re-use the x input array as a memory optimisation.

    bfp_s32_t inv_X_energy_bfp[IC_X_CHANNELS]

      BFP array pointing to the inverse X energies used for normalisation.

    int32_t inv_X_energy[IC_X_CHANNELS][IC_FD_FRAME_LENGTH]

      Storage for inv_X_energy mantissas.

    bfp_s32_t X_energy_bfp[IC_X_CHANNELS]

      BFP array pointing to the X energies.

    int32_t X_energy[IC_X_CHANNELS][IC_FD_FRAME_LENGTH]

      Storage for X_energy mantissas.

    unsigned X_energy_recalc_bin

      Index state used for calculating energy across all X bins.

    bfp_s32_t overlap_bfp[IC_Y_CHANNELS]

      BFP array pointing to the overlap array used for windowing and overlap operations.

    int32_t overlap[IC_Y_CHANNELS][IC_FRAME_OVERLAP]

      Storage for overlap mantissas.

    int32_t y_input_delay[IC_Y_CHANNELS][IC_Y_CHANNEL_DELAY_SAMPS]

      FIFO for delaying y channel (w.r.t x) to enable adaptive filter to be effective.

    uint32_t y_delay_idx[IC_Y_CHANNELS]

      Index state used for keeping track of y delay FIFO.

    float_s32_t mu[IC_Y_CHANNELS][IC_X_CHANNELS]

      Mu value used for controlling adaption rate.

    float_s32_t leakage_alpha

      Alpha used for leaking away H_hat, allowing filter to slowly forget adaption.

    float_s32_t max_X_energy[IC_X_CHANNELS]

      Used to keep track of peak X energy.

    bfp_s32_t sigma_XX_bfp[IC_X_CHANNELS]

      BFP array pointing to the EMA filtered X input energy.

    int32_t sigma_XX[IC_X_CHANNELS][IC_FD_FRAME_LENGTH]

      Storage for sigma_XX mantissas.

    float_s32_t sum_X_energy[IC_X_CHANNELS]

      X energy sum used for maintaining the X FIFO.

    ic_config_params_t config_params

      Configuration parameters for the IC.

    ic_adaption_controller_state_t ic_adaption_controller_state

      State and configuration parameters for the IC adaption controller.

    vnr_pred_state_t vnr_pred_state

      Input and Output VNR Prediction related state