ref: aaf7c645525630b7e298c163b84b42cc89b8e2d8
parent: e0831a18c4ff69f2e676f1e9ce0775ffdaf4571b
author: menno <menno>
date: Wed Jan 5 16:40:18 EST 2000
Removed backward prediction
--- a/aac_back_pred.c
+++ /dev/null
@@ -1,295 +1,0 @@
-/**********************************************************************
-
-This software module was originally developed by
-and edited by Nokia in the course of
-development of the MPEG-2 NBC/MPEG-4 Audio standard
-ISO/IEC 13818-7, 14496-1,2 and 3. This software module is an
-implementation of a part of one or more MPEG-2 NBC/MPEG-4 Audio tools
-as specified by the MPEG-2 NBC/MPEG-4 Audio standard. ISO/IEC gives
-users of the MPEG-2 NBC/MPEG-4 Audio standards free license to this
-software module or modifications thereof for use in hardware or
-software products claiming conformance to the MPEG-2 NBC/ MPEG-4 Audio
-standards. Those intending to use this software module in hardware or
-software products are advised that this use may infringe existing
-patents. The original developer of this software module and his/her
-company, the subsequent editors and their companies, and ISO/IEC have
-no liability for use of this software module or modifications thereof
-in an implementation. Copyright is not released for non MPEG-2
-NBC/MPEG-4 Audio conforming products. The original developer retains
-full right to use the code for his/her own purpose, assign or donate
-the code to a third party and to inhibit third party from using the
-code for non MPEG-2 NBC/MPEG-4 Audio conforming products. This
-copyright notice must be included in all copies or derivative works.
-
-Copyright (c) 1997.
-**********************************************************************/
-/*********************************************************************
- *
- * aac_back_pred.c - AAC backward prediction subroutine
- *
- * Authors:
- * LY Lin Yin, Nokia Research Center
- * CL Chuck Lueck, TI <lueck@ti.com>
- * ADD Alberto Duenas, NDS <alberto@ndsuk.com)
- * JB Jeremy Bennett, NDS <jbennett@ndsuk.com>
- *
- * Changes:
- * 07-jun-97 LY Initial revision.
- * 14-sep-97 CL Made predicted samples array, sb_samples_pred, static.
- * Modified line 98 to add these predicted values to
- * the last spectrum prior to analysis.
- * 03-dec-97 ADD & JB Added prediction reset.
- *
-**********************************************************************/
-
-/**********************************************************************
-
-INPUT:
-act_spec[]: the current frame's spectral components to be encoded.
-last_spec[]: the previous frame's quantized spectral error components
-btype: the current frame's window type
-nsfb: the number of scalefactor bands
-isfb_width[]: scalefactor bandwidth
-
-OUTPUT:
-act_spec[]: the current frame's spectral error components to be encoded
-pred_global_flag: global prediction enable/disable flag
-pred_sbf_glag[]: enable/disable flag for each scalefactor band
-reset_group: number for the reset group => if -1, then no reset
-***********************************************************************/
-
-#include "aac_back_pred.h"
-
-
-int psy_init_mc[MAX_TIME_CHANNELS];
-double dr_mc[MAX_TIME_CHANNELS][LPC+1][FLEN_LONG/2],e_mc[MAX_TIME_CHANNELS][LPC+1+1][FLEN_LONG/2];
-double K_mc[MAX_TIME_CHANNELS][LPC+1][FLEN_LONG/2], R_mc[MAX_TIME_CHANNELS][LPC+1][FLEN_LONG/2];
-double VAR_mc[MAX_TIME_CHANNELS][LPC+1][FLEN_LONG/2], KOR_mc[MAX_TIME_CHANNELS][LPC+1][FLEN_LONG/2];
-double sb_samples_pred_mc[MAX_TIME_CHANNELS][FLEN_LONG/2];
-int thisLineNeedsResetting_mc[MAX_TIME_CHANNELS][FLEN_LONG/2];
-int reset_count_mc[MAX_TIME_CHANNELS];
-
-void PredInit(void)
-{- int i;
- for (i=0;i<MAX_TIME_CHANNELS;i++) {- psy_init_mc[i] = 0;
- reset_count_mc[i] = 0;
- }
-}
-
-void PredCalcPrediction( double *act_spec, double *last_spec, int btype,
- int nsfb, int *isfb_width, short *pred_global_flag,
- int *pred_sfb_flag, int *reset_group ,
- int chanNum)
-{- int i, k, j, cb_long;
- double num_bit, snr[SBMAX_L];
- double energy[FLEN_LONG/2], snr_p[FLEN_LONG/2], temp1, temp2;
-
- /* Set pointers for specified channel number */
- /* int psy_init; */
- int *psy_init;
- double (*dr)[FLEN_LONG/2],(*e)[FLEN_LONG/2];
- double (*K)[FLEN_LONG/2], (*R)[FLEN_LONG/2];
- double (*VAR)[FLEN_LONG/2], (*KOR)[FLEN_LONG/2];
- double *sb_samples_pred;
- int *thisLineNeedsResetting;
- /* int reset_count; */
- int *reset_count;
-
- /* psy_init = psy_init_mc[chanNum]; */
- psy_init = &psy_init_mc[chanNum];
- dr = &dr_mc[chanNum][0];
- e = &e_mc[chanNum][0];
- K = &K_mc[chanNum][0];
- R = &R_mc[chanNum][0];
- VAR = &VAR_mc[chanNum][0];
- KOR = &KOR_mc[chanNum][0];
- sb_samples_pred = &sb_samples_pred_mc[chanNum][0];
- thisLineNeedsResetting = &thisLineNeedsResetting_mc[chanNum][0];
- reset_count = &reset_count_mc[chanNum];
-
- *psy_init = (*psy_init && (btype!=2));
-
- if((*psy_init) == 0) {- for (j=0; j<FLEN_LONG/2; j++) {- thisLineNeedsResetting[j]=1;
- }
- *psy_init = 1;
- }
-
- if (btype==2) {- pred_global_flag[0]=0;
-
- /* As SHORT WINDOWS reset all the co-efficients, the count
- * must also be reset.
- */
- *reset_count = ((*reset_count) / RESET_FRAME) * RESET_FRAME;
- return;
- }
-
-
-
- /**************************************************/
- /* Compute state using last_spec */
- /**************************************************/
- for (i=0;i<FLEN_LONG/2;i++)
- {- /* e[0][i]=last_spec[i]; */
- e[0][i]=last_spec[i]+sb_samples_pred[i];
-
- for(j=1;j<=LPC;j++)
- e[j][i] = e[j-1][i]-K[j][i]*R[j-1][i];
-
- for(j=1;j<LPC;j++)
- dr[j][i] = K[j][i]*e[j-1][i];
-
- for(j=1;j<=LPC;j++) {- VAR[j][i] = ALPHA*VAR[j][i]+.5*(R[j-1][i]*R[j-1][i]+e[j-1][i]*e[j-1][i]);
- KOR[j][i] = ALPHA*KOR[j][i]+R[j-1][i]*e[j-1][i];
- }
-
- for(j=LPC-1;j>=1;j--)
- R[j][i] = A*(R[j-1][i]-dr[j][i]);
- R[0][i] = A*e[0][i];
- }
-
-
- /**************************************************/
- /* Reset state here if resets were sent */
- /**************************************************/
- for (i=0;i<FLEN_LONG/2;i++) {- if (thisLineNeedsResetting[i]) {- for (j = 0; j <= LPC; j++)
- {- K[j][i] = 0.0;
- dr[j][i] = 0.0;
- e[j][i] = 0.0;
- R[j][i] = 0.0;
- VAR[j][i] = 1.0;
- KOR[j][i] = 0.0;
- }
- }
- }
-
-
- /**************************************************/
- /* Compute predictor coefficients, predicted data */
- /**************************************************/
- for (i=0;i<FLEN_LONG/2;i++)
- {- for(j=1;j<=LPC;j++) {- if(VAR[j][i]>MINVAR)
- K[j][i] = KOR[j][i]/VAR[j][i]*B;
- else
- K[j][i] = 0;
- }
- }
-
-
- for (k=0; k<FLEN_LONG/2; k++)
- {- sb_samples_pred[k]=0.0;
- for (i=1; i<=LPC; i++)
- sb_samples_pred[k]+=K[i][k]*R[i-1][k];
- }
-
-
-
- /**************************************************/
- /* Determine whether to enable/disable prediction */
- /**************************************************/
-
- for (k=0; k<FLEN_LONG/2; k++)
- {- energy[k]=act_spec[k]*act_spec[k];
- snr_p[k]=(act_spec[k]-sb_samples_pred[k])*(act_spec[k]-sb_samples_pred[k]);
- }
-
- cb_long=0;
- for (i=0; i<nsfb; i++)
- {- pred_sfb_flag[i]=1;
- temp1=0.0;
- temp2=0.0;
- for (j=cb_long; j<cb_long+isfb_width[i]; j++)
- {- temp1+=energy[j];
- temp2+=snr_p[j];
- }
- if(temp2<1.e-20)
- temp2=1.e-20;
- if(temp1!=0.0) {- snr[i]=-10.*log10((double ) temp2/temp1);
- } else
- snr[i]=0.0;
- if(snr[i]<=0.0) {- pred_sfb_flag[i]=0;
- for (j=cb_long; j<cb_long+isfb_width[i]; j++)
- sb_samples_pred[j]=0.0;
- }
- cb_long+=isfb_width[i];
- }
-
- /* Disable prediction for bands nsfb through SBMAX_L */
- for (i=cb_long;i<FLEN_LONG/2;i++) {- sb_samples_pred[i]=0.0;
- }
- for (i=nsfb;i<SBMAX_L;i++) {- pred_sfb_flag[i]=0;
- }
-
- num_bit=0.0;
- for (i=0; i<nsfb; i++)
- if(snr[i]>0.0)
- num_bit+=snr[i]/6.*isfb_width[i];
-
- pred_global_flag[0]=1;
- if(num_bit < 50) {- pred_global_flag[0]=0; num_bit=0.0;
- for (j=0; j<FLEN_LONG/2; j++)
- sb_samples_pred[j]=0.0;
- }
- for (j=0; j<FLEN_LONG/2; j++)
- act_spec[j]-=sb_samples_pred[j];
-
- /* Code segment added by JB */
-
- /* Determine whether a prediction reset is required - if so, then
- * set reset flag for the appropriate group.
- */
- (*reset_count)++;
- /* Reset the frame counter */
- for (i=0;i<FLEN_LONG/2;i++) {- thisLineNeedsResetting[i]=0;
- }
- if (*reset_count >= 31 * RESET_FRAME)
- *reset_count = RESET_FRAME;
- if (*reset_count % RESET_FRAME == 0)
- { /* Send a reset in this frame */- *reset_group = *reset_count / 8;
-
- for (i = *reset_group - 1; i < FLEN_LONG / 2; i += 30)
- {- thisLineNeedsResetting[i]=1;
- }
- }
- else
- *reset_group = -1;
- /* End of code segment */
-
-
- /* Code segment added by JB */
-
- /* Ensure that prediction data is sent when there is a prediction
- * reset.
- */
- if (*reset_group != -1 && pred_global_flag[0] == 0)
- {- pred_global_flag[0] = 1;
- for (i = 0; i < nsfb; i++)
- pred_sfb_flag[i] = 0;
- }
- /* End of code segment */
-}
--- a/aac_back_pred.h
+++ /dev/null
@@ -1,74 +1,0 @@
-/**********************************************************************
-
-This software module was originally developed by
-and edited by Nokia in the course of
-development of the MPEG-2 NBC/MPEG-4 Audio standard
-ISO/IEC 13818-7, 14496-1,2 and 3. This software module is an
-implementation of a part of one or more MPEG-2 NBC/MPEG-4 Audio tools
-as specified by the MPEG-2 NBC/MPEG-4 Audio standard. ISO/IEC gives
-users of the MPEG-2 NBC/MPEG-4 Audio standards free license to this
-software module or modifications thereof for use in hardware or
-software products claiming conformance to the MPEG-2 NBC/ MPEG-4 Audio
-standards. Those intending to use this software module in hardware or
-software products are advised that this use may infringe existing
-patents. The original developer of this software module and his/her
-company, the subsequent editors and their companies, and ISO/IEC have
-no liability for use of this software module or modifications thereof
-in an implementation. Copyright is not released for non MPEG-2
-NBC/MPEG-4 Audio conforming products. The original developer retains
-full right to use the code for his/her own purpose, assign or donate
-the code to a third party and to inhibit third party from using the
-code for non MPEG-2 NBC/MPEG-4 Audio conforming products. This
-copyright notice must be included in all copies or derivative works.
-
-Copyright (c) 1997.
-**********************************************************************/
-/*********************************************************************
- *
- * aac_back_pred.c - AAC backward prediction subroutine
- *
- * Authors:
- * LY Lin Yin, Nokia Research Center
- * CL Chuck Lueck, TI <lueck@ti.com>
- * ADD Alberto Duenas, NDS <alberto@ndsuk.com>
- * JB Jeremy Bennett, NDS <jbennett@ndsuk.com>
- *
- * Changes:
- * 07-jun-97 LY Initial revision.
- * 14-sep-97 CL Updated ALPHA, A, and B coefficients.
- * 03-dec-97 ADD & JB Added prediction reset.
- *
-**********************************************************************/
-
-#ifndef _AAC_BACK_H_INCLUDED
-#define _AAC_BACK_H_INCLUDED
-
-#include <math.h>
-#include "interface.h"
-#include "all.h"
-
-#define FLEN_LONG 2048
-#define SBMAX_L 49
-#define LPC 2
-#define ALPHA PRED_ALPHA
-#define A PRED_A
-#define B PRED_B
-#define MINVAR 1.e-10
-
-/* Reset every RESET_FRAME frames. */
-#define RESET_FRAME 8
-
-void PredCalcPrediction( double *act_spec,
- double *last_spec,
- int btype,
- int nsfb,
- int *isfb_width,
- short *pred_global_flag,
- int *pred_sfb_flag,
- int *reset_group,
- int chanNum);
-
-void PredInit(void);
-
-#endif
-