2 * common functions for the ATRAC family of decoders
4 * Copyright (c) 2006-2013 Maxim Poliakovski
5 * Copyright (c) 2006-2008 Benjamin Larsson
7 * This file is part of FFmpeg.
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
36 float ff_atrac_sf_table
[64];
37 static float qmf_window
[48];
39 static const float qmf_48tap_half
[24] = {
40 -0.00001461907, -0.00009205479,-0.000056157569,0.00030117269,
41 0.0002422519, -0.00085293897,-0.0005205574, 0.0020340169,
42 0.00078333891, -0.0042153862, -0.00075614988, 0.0078402944,
43 -0.000061169922,-0.01344162, 0.0024626821, 0.021736089,
44 -0.007801671, -0.034090221, 0.01880949, 0.054326009,
45 -0.043596379, -0.099384367, 0.13207909, 0.46424159
48 av_cold
void ff_atrac_generate_tables(void)
53 /* Generate scale factors */
54 if (!ff_atrac_sf_table
[63])
55 for (i
=0 ; i
<64 ; i
++)
56 ff_atrac_sf_table
[i
] = pow(2.0, (i
- 15) / 3.0);
58 /* Generate the QMF window. */
60 for (i
=0 ; i
<24; i
++) {
61 s
= qmf_48tap_half
[i
] * 2.0;
62 qmf_window
[i
] = qmf_window
[47 - i
] = s
;
66 av_cold
void ff_atrac_init_gain_compensation(AtracGCContext
*gctx
, int id2exp_offset
,
71 gctx
->loc_scale
= loc_scale
;
72 gctx
->loc_size
= 1 << loc_scale
;
73 gctx
->id2exp_offset
= id2exp_offset
;
75 /* Generate gain level table. */
76 for (i
= 0; i
< 16; i
++)
77 gctx
->gain_tab1
[i
] = powf(2.0, id2exp_offset
- i
);
79 /* Generate gain interpolation table. */
80 for (i
= -15; i
< 16; i
++)
81 gctx
->gain_tab2
[i
+ 15] = powf(2.0, -1.0f
/ gctx
->loc_size
* i
);
84 void ff_atrac_gain_compensation(AtracGCContext
*gctx
, float *in
, float *prev
,
85 AtracGainInfo
*gc_now
, AtracGainInfo
*gc_next
,
86 int num_samples
, float *out
)
88 float lev
, gc_scale
, gain_inc
;
91 gc_scale
= gc_next
->num_points
? gctx
->gain_tab1
[gc_next
->lev_code
[0]]
94 if (!gc_now
->num_points
) {
95 for (pos
= 0; pos
< num_samples
; pos
++)
96 out
[pos
] = in
[pos
] * gc_scale
+ prev
[pos
];
100 for (i
= 0; i
< gc_now
->num_points
; i
++) {
101 lastpos
= gc_now
->loc_code
[i
] << gctx
->loc_scale
;
103 lev
= gctx
->gain_tab1
[gc_now
->lev_code
[i
]];
104 gain_inc
= gctx
->gain_tab2
[(i
+ 1 < gc_now
->num_points
? gc_now
->lev_code
[i
+ 1]
105 : gctx
->id2exp_offset
) -
106 gc_now
->lev_code
[i
] + 15];
108 /* apply constant gain level and overlap */
109 for (; pos
< lastpos
; pos
++)
110 out
[pos
] = (in
[pos
] * gc_scale
+ prev
[pos
]) * lev
;
112 /* interpolate between two different gain levels */
113 for (; pos
< lastpos
+ gctx
->loc_size
; pos
++) {
114 out
[pos
] = (in
[pos
] * gc_scale
+ prev
[pos
]) * lev
;
119 for (; pos
< num_samples
; pos
++)
120 out
[pos
] = in
[pos
] * gc_scale
+ prev
[pos
];
123 /* copy the overlapping part into the delay buffer */
124 memcpy(prev
, &in
[num_samples
], num_samples
* sizeof(float));
127 void ff_atrac_iqmf(float *inlo
, float *inhi
, unsigned int nIn
, float *pOut
,
128 float *delayBuf
, float *temp
)
133 memcpy(temp
, delayBuf
, 46*sizeof(float));
138 for(i
=0; i
<nIn
; i
+=2){
139 p3
[2*i
+0] = inlo
[i
] + inhi
[i
];
140 p3
[2*i
+1] = inlo
[i
] - inhi
[i
];
141 p3
[2*i
+2] = inlo
[i
+1] + inhi
[i
+1];
142 p3
[2*i
+3] = inlo
[i
+1] - inhi
[i
+1];
147 for (j
= nIn
; j
!= 0; j
--) {
151 for (i
= 0; i
< 48; i
+= 2) {
152 s1
+= p1
[i
] * qmf_window
[i
];
153 s2
+= p1
[i
+1] * qmf_window
[i
+1];
163 /* Update the delay buffer. */
164 memcpy(delayBuf
, temp
+ nIn
*2, 46*sizeof(float));