1/*
2 * Copyright (c) 2012
3 *      MIPS Technologies, Inc., California.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
14 *    contributors may be used to endorse or promote products derived from
15 *    this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * Author:  Stanislav Ocovaj (socovaj@mips.com)
30 *
31 * AC3 fixed-point decoder for MIPS platforms
32 *
33 * This file is part of FFmpeg.
34 *
35 * FFmpeg is free software; you can redistribute it and/or
36 * modify it under the terms of the GNU Lesser General Public
37 * License as published by the Free Software Foundation; either
38 * version 2.1 of the License, or (at your option) any later version.
39 *
40 * FFmpeg is distributed in the hope that it will be useful,
41 * but WITHOUT ANY WARRANTY; without even the implied warranty of
42 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
43 * Lesser General Public License for more details.
44 *
45 * You should have received a copy of the GNU Lesser General Public
46 * License along with FFmpeg; if not, write to the Free Software
47 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
48 */
49
50#define FFT_FLOAT 0
51#define USE_FIXED 1
52#define FFT_FIXED_32 1
53#include "ac3dec.h"
54
55
56/**
57 * Table for center mix levels
58 * reference: Section 5.4.2.4 cmixlev
59 */
60static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
61
62/**
63 * Table for surround mix levels
64 * reference: Section 5.4.2.5 surmixlev
65 */
66static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
67
68int end_freq_inv_tab[8] =
69{
70    50529027, 44278013, 39403370, 32292987, 27356480, 23729101, 20951060, 18755316
71};
72
73static void scale_coefs (
74    int32_t *dst,
75    const int32_t *src,
76    int dynrng,
77    int len)
78{
79    int i, shift, round;
80    int16_t mul;
81    int temp, temp1, temp2, temp3, temp4, temp5, temp6, temp7;
82
83    mul = (dynrng & 0x1f) + 0x20;
84    shift = 4 - ((dynrng << 24) >> 29);
85    round = 1 << (shift-1);
86    for (i=0; i<len; i+=8) {
87
88        temp = src[i] * mul;
89        temp1 = src[i+1] * mul;
90        temp = temp + round;
91        temp2 = src[i+2] * mul;
92
93        temp1 = temp1 + round;
94        dst[i] = temp >> shift;
95        temp3 = src[i+3] * mul;
96        temp2 = temp2 + round;
97
98        dst[i+1] = temp1 >> shift;
99        temp4 = src[i + 4] * mul;
100        temp3 = temp3 + round;
101        dst[i+2] = temp2 >> shift;
102
103        temp5 = src[i+5] * mul;
104        temp4 = temp4 + round;
105        dst[i+3] = temp3 >> shift;
106        temp6 = src[i+6] * mul;
107
108        dst[i+4] = temp4 >> shift;
109        temp5 = temp5 + round;
110        temp7 = src[i+7] * mul;
111        temp6 = temp6 + round;
112
113        dst[i+5] = temp5 >> shift;
114        temp7 = temp7 + round;
115        dst[i+6] = temp6 >> shift;
116        dst[i+7] = temp7 >> shift;
117
118    }
119}
120
121/**
122 * Downmix samples from original signal to stereo or mono (this is for 16-bit samples
123 * and fixed point decoder - original (for 32-bit samples) is in ac3dsp.c).
124 */
125static void ac3_downmix_c_fixed16(int16_t **samples, int16_t (*matrix)[2],
126                                  int out_ch, int in_ch, int len)
127{
128    int i, j;
129    int v0, v1;
130    if (out_ch == 2) {
131        for (i = 0; i < len; i++) {
132            v0 = v1 = 0;
133            for (j = 0; j < in_ch; j++) {
134                v0 += samples[j][i] * matrix[j][0];
135                v1 += samples[j][i] * matrix[j][1];
136            }
137            samples[0][i] = (v0+2048)>>12;
138            samples[1][i] = (v1+2048)>>12;
139        }
140    } else if (out_ch == 1) {
141        for (i = 0; i < len; i++) {
142            v0 = 0;
143            for (j = 0; j < in_ch; j++)
144                v0 += samples[j][i] * matrix[j][0];
145            samples[0][i] = (v0+2048)>>12;
146        }
147    }
148}
149
150#include "ac3dec.c"
151
152static const AVOption options[] = {
153    { NULL},
154};
155
156static const AVClass ac3_decoder_class = {
157    .class_name = "Fixed-Point AC-3 Decoder",
158    .item_name  = av_default_item_name,
159    .option     = options,
160    .version    = LIBAVUTIL_VERSION_INT,
161};
162
163AVCodec ff_ac3_fixed_decoder = {
164    .name           = "ac3_fixed",
165    .type           = AVMEDIA_TYPE_AUDIO,
166    .id             = AV_CODEC_ID_AC3,
167    .priv_data_size = sizeof (AC3DecodeContext),
168    .init           = ac3_decode_init,
169    .close          = ac3_decode_end,
170    .decode         = ac3_decode_frame,
171    .capabilities   = CODEC_CAP_DR1,
172    .long_name      = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
173    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
174                                                      AV_SAMPLE_FMT_NONE },
175    .priv_class     = &ac3_decoder_class,
176};
177