Author: kmalaussene Date: Wed Mar 4 19:34:41 2009 New Revision: 4156 Log: Factor out gains decoding into decode_gains function, to make the main loop more readable and allow further simplifications. Modified: amr/amrnbfloatdec.c Modified: amr/amrnbfloatdec.c ============================================================================== --- amr/amrnbfloatdec.c Wed Mar 4 01:06:52 2009 (r4155) +++ amr/amrnbfloatdec.c Wed Mar 4 19:34:41 2009 (r4156) @@ -685,6 +685,51 @@ static float fixed_gain_prediction(float return powf(10.0, 0.05*(energy_pred + energy_mean[mode] - energy_fixed_mean)); } +/** + * Decode fixed and pitch gains. + * + * @param p the context + * @param amr_subframe unpacked amr subframe + * @param mode mode of the current frame + * @param subframe current subframe number + */ + +static void decode_gains(AMRContext *p, const AMRNBSubframe *amr_subframe, const enum Mode mode, const int subframe) +{ + static int gains_index_MODE_475; + + // decode pitch gain and fixed gain correction factor + if(mode == MODE_122 || mode == MODE_795) { + p->pitch_gain[4] = qua_gain_pit [amr_subframe->p_gain]; + p->fixed_gain_factor = qua_gain_code[amr_subframe->fixed_gain]; + }else if(mode >= MODE_67) { + p->pitch_gain[4] = gains_high[amr_subframe->p_gain][0]; + p->fixed_gain_factor = gains_high[amr_subframe->p_gain][1]; + }else if(mode >= MODE_515) { + p->pitch_gain[4] = gains_low[amr_subframe->p_gain][0]; + p->fixed_gain_factor = gains_low[amr_subframe->p_gain][1]; + }else { + // gain index is only coded in subframes 0,2 + if(!(subframe&1)) { + gains_index_MODE_475 = amr_subframe->p_gain<<1; + } + p->pitch_gain[4] = gains_MODE_475[gains_index_MODE_475 + (subframe&1)][0]; + p->fixed_gain_factor = gains_MODE_475[gains_index_MODE_475 + (subframe&1)][1]; + } + + // calculate the predicted fixed gain g_c' + p->fixed_gain[4] = fixed_gain_prediction(p->fixed_vector, p->prediction_error, mode); + + // ^g_c = g_c' * ^gamma_gc + p->fixed_gain[4] *= p->fixed_gain_factor; + + // update quantified prediction error energy history + p->prediction_error[0] = p->prediction_error[1]; + p->prediction_error[1] = p->prediction_error[2]; + p->prediction_error[2] = p->prediction_error[3]; + p->prediction_error[3] = 20.0*log10f(p->fixed_gain_factor); +} + /// @} @@ -835,12 +880,6 @@ static void update_state(AMRContext *p) memmove(&p->excitation_buf[0], &p->excitation_buf[AMR_SUBFRAME_SIZE], (PITCH_LAG_MAX + LP_FILTER_ORDER + 1)*sizeof(float)); - // update quantified prediction error energy history - p->prediction_error[0] = p->prediction_error[1]; - p->prediction_error[1] = p->prediction_error[2]; - p->prediction_error[2] = p->prediction_error[3]; - p->prediction_error[3] = 20.0*log10f(p->fixed_gain_factor); - // update gain history memmove(&p->pitch_gain[0], &p->pitch_gain[1], 4*sizeof(float)); memmove(&p->fixed_gain[0], &p->fixed_gain[1], 4*sizeof(float)); @@ -861,7 +900,6 @@ static int amrnb_decode_frame(AVCodecCon AMRContext *p = avctx->priv_data; // pointer to private data float *buf_out = data; // pointer to the output data buffer int i, subframe; // counters - int gains_index_MODE_475 = 0; // MODE_475 gains index coded every other subframe enum Mode speech_mode = MODE_475; // ??? // decode the bitstream to AMR parameters @@ -899,34 +937,7 @@ static int amrnb_decode_frame(AVCodecCon decode_fixed_vector(p->fixed_vector, amr_subframe->pulses, p->cur_frame_mode, subframe); -/*** gain decoding ***/ - - // calculate the predicted fixed gain g_c' - p->fixed_gain[4] = fixed_gain_prediction(p->fixed_vector, p->prediction_error, p->cur_frame_mode); - - // decode pitch gain and fixed gain correction factor - if(p->cur_frame_mode == MODE_122 || p->cur_frame_mode == MODE_795) { - p->pitch_gain[4] = qua_gain_pit [amr_subframe->p_gain]; - p->fixed_gain_factor = qua_gain_code[amr_subframe->fixed_gain]; - }else if(p->cur_frame_mode >= MODE_67) { - p->pitch_gain[4] = gains_high[amr_subframe->p_gain][0]; - p->fixed_gain_factor = gains_high[amr_subframe->p_gain][1]; - }else if(p->cur_frame_mode >= MODE_515) { - p->pitch_gain[4] = gains_low[amr_subframe->p_gain][0]; - p->fixed_gain_factor = gains_low[amr_subframe->p_gain][1]; - }else { - // gain index is only coded in subframes 0,2 - if(!(subframe&1)) { - gains_index_MODE_475 = amr_subframe->p_gain<<1; - } - p->pitch_gain[4] = gains_MODE_475[gains_index_MODE_475 + (subframe&1)][0]; - p->fixed_gain_factor = gains_MODE_475[gains_index_MODE_475 + (subframe&1)][1]; - } - - // ^g_c = g_c' * ^gamma_gc - p->fixed_gain[4] *= p->fixed_gain_factor; - -/*** end of gain decoding ***/ + decode_gains(p, amr_subframe, p->cur_frame_mode, subframe); /*** pre-processing ***/