2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
3 ** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
5 ** This program is free software; you can redistribute it and/or modify
6 ** it under the terms of the GNU General Public License as published by
7 ** the Free Software Foundation; either version 2 of the License, or
8 ** (at your option) any later version.
10 ** This program is distributed in the hope that it will be useful,
11 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
12 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 ** GNU General Public License for more details.
15 ** You should have received a copy of the GNU General Public License
16 ** along with this program; if not, write to the Free Software
17 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 ** Any non-GPL usage of this software or parts of this software is strictly
22 ** Commercial non-GPL licensing of this software is possible.
23 ** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
25 ** $Id: tns.c,v 1.35 2004/09/04 14:56:29 menno Exp $
35 /* static function declarations */
36 static void tns_decode_coef(uint8_t order
, uint8_t coef_res_bits
, uint8_t coef_compress
,
37 uint8_t *coef
, real_t
*a
);
38 static void tns_ar_filter(real_t
*spectrum
, uint16_t size
, int8_t inc
, real_t
*lpc
,
40 static void tns_ma_filter(real_t
*spectrum
, uint16_t size
, int8_t inc
, real_t
*lpc
,
45 #pragma warning(disable:4305)
46 #pragma warning(disable:4244)
48 static real_t tns_coef_0_3
[] =
50 COEF_CONST(0.0), COEF_CONST(0.4338837391), COEF_CONST(0.7818314825), COEF_CONST(0.9749279122),
51 COEF_CONST(-0.9848077530), COEF_CONST(-0.8660254038), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
52 COEF_CONST(-0.4338837391), COEF_CONST(-0.7818314825), COEF_CONST(-0.9749279122), COEF_CONST(-0.9749279122),
53 COEF_CONST(-0.9848077530), COEF_CONST(-0.8660254038), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433)
55 static real_t tns_coef_0_4
[] =
57 COEF_CONST(0.0), COEF_CONST(0.2079116908), COEF_CONST(0.4067366431), COEF_CONST(0.5877852523),
58 COEF_CONST(0.7431448255), COEF_CONST(0.8660254038), COEF_CONST(0.9510565163), COEF_CONST(0.9945218954),
59 COEF_CONST(-0.9957341763), COEF_CONST(-0.9618256432), COEF_CONST(-0.8951632914), COEF_CONST(-0.7980172273),
60 COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178)
62 static real_t tns_coef_1_3
[] =
64 COEF_CONST(0.0), COEF_CONST(0.4338837391), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
65 COEF_CONST(0.9749279122), COEF_CONST(0.7818314825), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
66 COEF_CONST(-0.4338837391), COEF_CONST(-0.7818314825), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
67 COEF_CONST(-0.7818314825), COEF_CONST(-0.4338837391), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433)
69 static real_t tns_coef_1_4
[] =
71 COEF_CONST(0.0), COEF_CONST(0.2079116908), COEF_CONST(0.4067366431), COEF_CONST(0.5877852523),
72 COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178),
73 COEF_CONST(0.9945218954), COEF_CONST(0.9510565163), COEF_CONST(0.8660254038), COEF_CONST(0.7431448255),
74 COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178)
78 /* TNS decoding for one channel and frame */
79 void tns_decode_frame(ic_stream
*ics
, tns_info
*tns
, uint8_t sr_index
,
80 uint8_t object_type
, real_t
*spec
, uint16_t frame_len
)
82 uint8_t w
, f
, tns_order
;
85 uint16_t bottom
, top
, start
, end
;
86 uint16_t nshort
= frame_len
/8;
87 real_t lpc
[TNS_MAX_ORDER
+1];
89 if (!ics
->tns_data_present
)
92 for (w
= 0; w
< ics
->num_windows
; w
++)
94 bottom
= ics
->num_swb
;
96 for (f
= 0; f
< tns
->n_filt
[w
]; f
++)
99 bottom
= max(top
- tns
->length
[w
][f
], 0);
100 tns_order
= min(tns
->order
[w
][f
], TNS_MAX_ORDER
);
104 tns_decode_coef(tns_order
, tns
->coef_res
[w
]+3,
105 tns
->coef_compress
[w
][f
], tns
->coef
[w
][f
], lpc
);
107 start
= min(bottom
, max_tns_sfb(sr_index
, object_type
, (ics
->window_sequence
== EIGHT_SHORT_SEQUENCE
)));
108 start
= min(start
, ics
->max_sfb
);
109 start
= ics
->swb_offset
[start
];
111 end
= min(top
, max_tns_sfb(sr_index
, object_type
, (ics
->window_sequence
== EIGHT_SHORT_SEQUENCE
)));
112 end
= min(end
, ics
->max_sfb
);
113 end
= ics
->swb_offset
[end
];
119 if (tns
->direction
[w
][f
])
127 tns_ar_filter(&spec
[(w
*nshort
)+start
], size
, inc
, lpc
, tns_order
);
132 /* TNS encoding for one channel and frame */
133 void tns_encode_frame(ic_stream
*ics
, tns_info
*tns
, uint8_t sr_index
,
134 uint8_t object_type
, real_t
*spec
, uint16_t frame_len
)
136 uint8_t w
, f
, tns_order
;
139 uint16_t bottom
, top
, start
, end
;
140 uint16_t nshort
= frame_len
/8;
141 real_t lpc
[TNS_MAX_ORDER
+1];
143 if (!ics
->tns_data_present
)
146 for (w
= 0; w
< ics
->num_windows
; w
++)
148 bottom
= ics
->num_swb
;
150 for (f
= 0; f
< tns
->n_filt
[w
]; f
++)
153 bottom
= max(top
- tns
->length
[w
][f
], 0);
154 tns_order
= min(tns
->order
[w
][f
], TNS_MAX_ORDER
);
158 tns_decode_coef(tns_order
, tns
->coef_res
[w
]+3,
159 tns
->coef_compress
[w
][f
], tns
->coef
[w
][f
], lpc
);
161 start
= min(bottom
, max_tns_sfb(sr_index
, object_type
, (ics
->window_sequence
== EIGHT_SHORT_SEQUENCE
)));
162 start
= min(start
, ics
->max_sfb
);
163 start
= ics
->swb_offset
[start
];
165 end
= min(top
, max_tns_sfb(sr_index
, object_type
, (ics
->window_sequence
== EIGHT_SHORT_SEQUENCE
)));
166 end
= min(end
, ics
->max_sfb
);
167 end
= ics
->swb_offset
[end
];
173 if (tns
->direction
[w
][f
])
181 tns_ma_filter(&spec
[(w
*nshort
)+start
], size
, inc
, lpc
, tns_order
);
186 /* Decoder transmitted coefficients for one TNS filter */
187 static void tns_decode_coef(uint8_t order
, uint8_t coef_res_bits
, uint8_t coef_compress
,
188 uint8_t *coef
, real_t
*a
)
191 real_t tmp2
[TNS_MAX_ORDER
+1], b
[TNS_MAX_ORDER
+1];
193 /* Conversion to signed integer */
194 for (i
= 0; i
< order
; i
++)
196 if (coef_compress
== 0)
198 if (coef_res_bits
== 3)
200 tmp2
[i
] = tns_coef_0_3
[coef
[i
]];
202 tmp2
[i
] = tns_coef_0_4
[coef
[i
]];
205 if (coef_res_bits
== 3)
207 tmp2
[i
] = tns_coef_1_3
[coef
[i
]];
209 tmp2
[i
] = tns_coef_1_4
[coef
[i
]];
214 /* Conversion to LPC coefficients */
215 a
[0] = COEF_CONST(1.0);
216 for (m
= 1; m
<= order
; m
++)
218 for (i
= 1; i
< m
; i
++) /* loop only while i<m */
219 b
[i
] = a
[i
] + MUL_C(tmp2
[m
-1], a
[m
-i
]);
221 for (i
= 1; i
< m
; i
++) /* loop only while i<m */
224 a
[m
] = tmp2
[m
-1]; /* changed */
228 static void tns_ar_filter(real_t
*spectrum
, uint16_t size
, int8_t inc
, real_t
*lpc
,
232 - Simple all-pole filter of order "order" defined by
233 y(n) = x(n) - lpc[1]*y(n-1) - ... - lpc[order]*y(n-order)
234 - The state variables of the filter are initialized to zero every time
235 - The output data is written over the input data ("in-place operation")
236 - An input vector of "size" samples is processed and the index increment
237 to the next data sample is given by "inc"
243 /* state is stored as a double ringbuffer */
244 real_t state
[2*TNS_MAX_ORDER
] = {0};
245 int8_t state_index
= 0;
247 for (i
= 0; i
< size
; i
++)
251 for (j
= 0; j
< order
; j
++)
252 y
-= MUL_C(state
[state_index
+j
], lpc
[j
+1]);
254 /* double ringbuffer state */
257 state_index
= order
-1;
258 state
[state_index
] = state
[state_index
+ order
] = y
;
266 printf("0x%.8X\n", y
);
271 static void tns_ma_filter(real_t
*spectrum
, uint16_t size
, int8_t inc
, real_t
*lpc
,
275 - Simple all-zero filter of order "order" defined by
276 y(n) = x(n) + a(2)*x(n-1) + ... + a(order+1)*x(n-order)
277 - The state variables of the filter are initialized to zero every time
278 - The output data is written over the input data ("in-place operation")
279 - An input vector of "size" samples is processed and the index increment
280 to the next data sample is given by "inc"
286 /* state is stored as a double ringbuffer */
287 real_t state
[2*TNS_MAX_ORDER
] = {0};
288 int8_t state_index
= 0;
290 for (i
= 0; i
< size
; i
++)
294 for (j
= 0; j
< order
; j
++)
295 y
+= MUL_C(state
[j
], lpc
[j
+1]);
297 /* double ringbuffer state */
300 state_index
= order
-1;
301 state
[state_index
] = state
[state_index
+ order
] = *spectrum
;