2 * copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "synth_filter.h"
24 static void synth_filter_float(FFTContext
*imdct
,
25 float *synth_buf_ptr
, int *synth_buf_offset
,
26 float synth_buf2
[32], const float window
[512],
27 float out
[32], const float in
[32], float scale
)
29 float *synth_buf
= synth_buf_ptr
+ *synth_buf_offset
;
32 imdct
->imdct_half(imdct
, synth_buf
, in
);
34 for (i
= 0; i
< 16; i
++){
35 float a
= synth_buf2
[i
];
36 float b
= synth_buf2
[i
+ 16];
39 for (j
= 0; j
< 512 - *synth_buf_offset
; j
+= 64){
40 a
+= window
[i
+ j
]*(-synth_buf
[15 - i
+ j
]);
41 b
+= window
[i
+ j
+ 16]*( synth_buf
[ i
+ j
]);
42 c
+= window
[i
+ j
+ 32]*( synth_buf
[16 + i
+ j
]);
43 d
+= window
[i
+ j
+ 48]*( synth_buf
[31 - i
+ j
]);
45 for ( ; j
< 512; j
+= 64){
46 a
+= window
[i
+ j
]*(-synth_buf
[15 - i
+ j
- 512]);
47 b
+= window
[i
+ j
+ 16]*( synth_buf
[ i
+ j
- 512]);
48 c
+= window
[i
+ j
+ 32]*( synth_buf
[16 + i
+ j
- 512]);
49 d
+= window
[i
+ j
+ 48]*( synth_buf
[31 - i
+ j
- 512]);
52 out
[i
+ 16] = b
*scale
;
54 synth_buf2
[i
+ 16] = d
;
56 *synth_buf_offset
= (*synth_buf_offset
- 32)&511;
59 av_cold
void ff_synth_filter_init(SynthFilterContext
*c
)
61 c
->synth_filter_float
= synth_filter_float
;
63 if (ARCH_ARM
) ff_synth_filter_init_arm(c
);
64 if (ARCH_X86
) ff_synth_filter_init_x86(c
);