| /* |
| ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding |
| ** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com |
| ** |
| ** This program is free software; you can redistribute it and/or modify |
| ** it under the terms of the GNU General Public License as published by |
| ** the Free Software Foundation; either version 2 of the License, or |
| ** (at your option) any later version. |
| ** |
| ** This program is distributed in the hope that it will be useful, |
| ** but WITHOUT ANY WARRANTY; without even the implied warranty of |
| ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| ** GNU General Public License for more details. |
| ** |
| ** You should have received a copy of the GNU General Public License |
| ** along with this program; if not, write to the Free Software |
| ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| ** |
| ** Any non-GPL usage of this software or parts of this software is strictly |
| ** forbidden. |
| ** |
| ** The "appropriate copyright message" mentioned in section 2c of the GPLv2 |
| ** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com" |
| ** |
| ** Commercial non-GPL licensing of this software is possible. |
| ** For more info contact Nero AG through Mpeg4AAClicense@nero.com. |
| ** |
| ** $Id: lt_predict.c,v 1.27 2007/11/01 12:33:31 menno Exp $ |
| **/ |
| |
| |
| #include "common.h" |
| #include "structs.h" |
| |
| #ifdef LTP_DEC |
| |
| #include "syntax.h" |
| #include "lt_predict.h" |
| #include "filtbank.h" |
| #include "tns.h" |
| |
| |
| /* static function declarations */ |
| static int16_t real_to_int16(real_t sig_in); |
| |
| |
| /* check if the object type is an object type that can have LTP */ |
| uint8_t is_ltp_ot(uint8_t object_type) |
| { |
| #ifdef LTP_DEC |
| if ((object_type == LTP) |
| #ifdef ERROR_RESILIENCE |
| || (object_type == ER_LTP) |
| #endif |
| #ifdef LD_DEC |
| || (object_type == LD) |
| #endif |
| ) { |
| return 1; |
| } |
| #endif |
| |
| return 0; |
| } |
| |
| ALIGN static const real_t codebook[8] = { |
| REAL_CONST(0.570829), |
| REAL_CONST(0.696616), |
| REAL_CONST(0.813004), |
| REAL_CONST(0.911304), |
| REAL_CONST(0.984900), |
| REAL_CONST(1.067894), |
| REAL_CONST(1.194601), |
| REAL_CONST(1.369533) |
| }; |
| |
| void lt_prediction(ic_stream *ics, ltp_info *ltp, real_t *spec, |
| int16_t *lt_pred_stat, fb_info *fb, uint8_t win_shape, |
| uint8_t win_shape_prev, uint8_t sr_index, |
| uint8_t object_type, uint16_t frame_len) |
| { |
| uint8_t sfb; |
| uint16_t bin, i, num_samples; |
| ALIGN static real_t x_est[2048]; |
| ALIGN static real_t X_est[2048]; |
| memset(x_est, 0, sizeof(x_est)); |
| memset(X_est, 0, sizeof(X_est)); |
| |
| if (ics->window_sequence != EIGHT_SHORT_SEQUENCE) { |
| if (ltp->data_present) { |
| num_samples = frame_len << 1; |
| |
| for (i = 0; i < num_samples; i++) { |
| /* The extra lookback M (N/2 for LD, 0 for LTP) is handled |
| in the buffer updating */ |
| |
| #if 0 |
| x_est[i] = MUL_R_C(lt_pred_stat[num_samples + i - ltp->lag], |
| codebook[ltp->coef]); |
| #else |
| /* lt_pred_stat is a 16 bit int, multiplied with the fixed point real |
| this gives a real for x_est |
| */ |
| x_est[i] = (real_t)lt_pred_stat[num_samples + i - ltp->lag] * codebook[ltp->coef]; |
| #endif |
| } |
| |
| filter_bank_ltp(fb, ics->window_sequence, win_shape, win_shape_prev, |
| x_est, X_est, object_type, frame_len); |
| |
| tns_encode_frame(ics, &(ics->tns), sr_index, object_type, X_est, |
| frame_len); |
| |
| for (sfb = 0; sfb < ltp->last_band; sfb++) { |
| if (ltp->long_used[sfb]) { |
| uint16_t low = ics->swb_offset[sfb]; |
| uint16_t high = min(ics->swb_offset[sfb + 1], ics->swb_offset_max); |
| |
| for (bin = low; bin < high; bin++) { |
| spec[bin] += X_est[bin]; |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| #ifdef FIXED_POINT |
| static INLINE int16_t real_to_int16(real_t sig_in) |
| { |
| if (sig_in >= 0) { |
| sig_in += (1 << (REAL_BITS - 1)); |
| if (sig_in >= REAL_CONST(32768)) { |
| return 32767; |
| } |
| } else { |
| sig_in += -(1 << (REAL_BITS - 1)); |
| if (sig_in <= REAL_CONST(-32768)) { |
| return -32768; |
| } |
| } |
| |
| return (sig_in >> REAL_BITS); |
| } |
| #else |
| static INLINE int16_t real_to_int16(real_t sig_in) |
| { |
| if (sig_in >= 0) { |
| #ifndef HAS_LRINTF |
| sig_in += 0.5f; |
| #endif |
| if (sig_in >= 32768.0f) { |
| return 32767; |
| } |
| } else { |
| #ifndef HAS_LRINTF |
| sig_in += -0.5f; |
| #endif |
| if (sig_in <= -32768.0f) { |
| return -32768; |
| } |
| } |
| |
| return lrintf(sig_in); |
| } |
| #endif |
| |
| void lt_update_state(int16_t *lt_pred_stat, real_t *time, real_t *overlap, |
| uint16_t frame_len, uint8_t object_type) |
| { |
| uint16_t i; |
| |
| /* |
| * The reference point for index i and the content of the buffer |
| * lt_pred_stat are arranged so that lt_pred_stat(0 ... N/2 - 1) contains the |
| * last aliased half window from the IMDCT, and lt_pred_stat(N/2 ... N-1) |
| * is always all zeros. The rest of lt_pred_stat (i<0) contains the previous |
| * fully reconstructed time domain samples, i.e., output of the decoder. |
| * |
| * These values are shifted up by N*2 to avoid (i<0) |
| * |
| * For the LD object type an extra 512 samples lookback is accomodated here. |
| */ |
| #ifdef LD_DEC |
| if (object_type == LD) { |
| for (i = 0; i < frame_len; i++) { |
| lt_pred_stat[i] /* extra 512 */ = lt_pred_stat[i + frame_len]; |
| lt_pred_stat[frame_len + i] = lt_pred_stat[i + (frame_len * 2)]; |
| lt_pred_stat[(frame_len * 2) + i] = real_to_int16(time[i]); |
| lt_pred_stat[(frame_len * 3) + i] = real_to_int16(overlap[i]); |
| } |
| } else { |
| #endif |
| for (i = 0; i < frame_len; i++) { |
| lt_pred_stat[i] = lt_pred_stat[i + frame_len]; |
| lt_pred_stat[frame_len + i] = real_to_int16(time[i]); |
| lt_pred_stat[(frame_len * 2) + i] = real_to_int16(overlap[i]); |
| #if 0 /* set to zero once upon initialisation */ |
| lt_pred_stat[(frame_len * 3) + i] = 0; |
| #endif |
| } |
| #ifdef LD_DEC |
| } |
| #endif |
| } |
| |
| #endif |