libxaac/decoder/drc_src/impd_drc_multiband.c

/******************************************************************************
 *
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *****************************************************************************
 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "impd_type_def.h"
#include "impd_error_standards.h"
#include "impd_drc_extr_delta_coded_info.h"
#include "impd_drc_common.h"
#include "impd_drc_struct.h"
#include "impd_drc_filter_bank.h"
#include "impd_drc_multi_band.h"
#include "impd_drc_rom.h"

IA_ERRORCODE impd_fcenter_norm_sb_init(WORD32 num_subbands,
                  FLOAT32* fcenter_norm_subband)
{
    WORD32 s;
    for (s=0; s<num_subbands; s++) {
        fcenter_norm_subband[s] = (s + 0.5f) / (2.0f * num_subbands);
    }
    return (0);
}

IA_ERRORCODE   impd_generate_slope (WORD32 num_sub_bands,
                        FLOAT32* fcenter_norm_subband,
                        FLOAT32 fcross_norm_lo,
                        FLOAT32 fcross_norm_hi,
                        FLOAT32* response)
{
    WORD32 i;
    FLOAT32 filter_slope =-24.0f;
    FLOAT32 inv_log10_2  =3.32192809f;
    FLOAT32 norm = 0.05f * filter_slope * inv_log10_2;

    for (i=0; i<num_sub_bands; i++)
    {
        if (fcenter_norm_subband[i] < fcross_norm_lo)
        {
            response[i] = (FLOAT32)pow (10.0, norm * log10(fcross_norm_lo / fcenter_norm_subband[i]));
        }
        else if (fcenter_norm_subband[i] < fcross_norm_hi)
        {
            response[i] = 1.0f;
        }
        else
        {
            response[i] = (FLOAT32)pow (10.0, norm * log10(fcenter_norm_subband[i] / fcross_norm_hi));
        }
    }
    return (0);
}


IA_ERRORCODE impd_generate_overlap_weights (WORD32 num_drc_bands,
                                      WORD32 drc_band_type,
                                       ia_gain_params_struct* gain_params,
                                      WORD32 dec_subband_count,
                                     ia_group_overlap_params_struct* pstr_group_overlap_params)
{
    FLOAT32 fcenter_norm_subband[AUDIO_CODEC_SUBBAND_COUNT_MAX];
    FLOAT32 w_norm[AUDIO_CODEC_SUBBAND_COUNT_MAX];
    FLOAT32 fcross_norm_lo, fcross_norm_hi;
    WORD32 err, b, s, start_subband_index = 0, stop_sub_band_index = 0;
    err = impd_fcenter_norm_sb_init(dec_subband_count, fcenter_norm_subband);

    if (drc_band_type == 1) {
        fcross_norm_lo = 0.0f;
        for (b=0; b<num_drc_bands; b++)
        {
            if (b<num_drc_bands - 1)
            {
                fcross_norm_hi = normal_cross_freq[gain_params[b+1].crossover_freq_idx].f_cross_norm;
            }
            else
            {
                fcross_norm_hi = 0.5f;
            }
            impd_generate_slope (dec_subband_count,
                           fcenter_norm_subband,
                           fcross_norm_lo,
                           fcross_norm_hi,
                           pstr_group_overlap_params->str_band_overlap_params[b].overlap_weight);

            fcross_norm_lo = fcross_norm_hi;
        }
        for (s=0; s<dec_subband_count; s++)
        {
            w_norm[s] = pstr_group_overlap_params->str_band_overlap_params[0].overlap_weight[s];
            for (b=1; b<num_drc_bands; b++)
            {
                w_norm[s] += pstr_group_overlap_params->str_band_overlap_params[b].overlap_weight[s];
            }
        }

        for (s=0; s<dec_subband_count; s++)
        {
            for (b=0; b<num_drc_bands; b++)
            {
                pstr_group_overlap_params->str_band_overlap_params[b].overlap_weight[s] /= w_norm[s];
            }
        }
    } else {
        start_subband_index = 0;
        for (b=0; b<num_drc_bands; b++)
        {
            if (b < num_drc_bands-1)
            {
                stop_sub_band_index = gain_params[b+1].start_subband_index-1;
            }
            else
            {
                stop_sub_band_index = dec_subband_count-1;
            }
            for (s=0; s<dec_subband_count; s++)
            {
                if (s >= start_subband_index && s <= stop_sub_band_index)
                {
                    pstr_group_overlap_params->str_band_overlap_params[b].overlap_weight[s] = 1.0;
                }
                else
                {
                    pstr_group_overlap_params->str_band_overlap_params[b].overlap_weight[s] = 0.0;
                }
            }
            start_subband_index = stop_sub_band_index+1;
        }
    }

    return (0);
}

IA_ERRORCODE impd_init_overlap_weight ( ia_uni_drc_coeffs_struct* str_p_loc_drc_coefficients_uni_drc,
                    ia_drc_instructions_struct* str_drc_instruction_str,
                   WORD32 sub_band_domain_mode,
                   ia_overlap_params_struct* pstr_overlap_params)
{
    WORD32 err = 0, g;
    WORD32 dec_subband_count = 0;
    switch (sub_band_domain_mode) {
        case SUBBAND_DOMAIN_MODE_QMF64:
            dec_subband_count              = AUDIO_CODEC_SUBBAND_COUNT_QMF64;
            break;
        case SUBBAND_DOMAIN_MODE_QMF71:
            dec_subband_count              = AUDIO_CODEC_SUBBAND_COUNT_QMF71;
            break;
        case SUBBAND_DOMAIN_MODE_STFT256:
            dec_subband_count              = AUDIO_CODEC_SUBBAND_COUNT_STFT256;
            break;
    }

    for (g=0; g<str_drc_instruction_str->num_drc_ch_groups; g++)
    {
        if (str_drc_instruction_str->band_count_of_ch_group[g] > 1)
        {
            err = impd_generate_overlap_weights(str_drc_instruction_str->band_count_of_ch_group[g],
                                         str_p_loc_drc_coefficients_uni_drc->gain_set_params[str_drc_instruction_str->gain_set_index_for_channel_group[g]].drc_band_type,
                                         str_p_loc_drc_coefficients_uni_drc->gain_set_params[str_drc_instruction_str->gain_set_index_for_channel_group[g]].gain_params,
                                         dec_subband_count,
                                         &(pstr_overlap_params->str_group_overlap_params[g]));
            if (err) return (err);
        }
    }

    return (0);
}