3 * MIPS Technologies, Inc., California.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
29 * Author: Stanislav Ocovaj (socovaj@mips.com)
31 * AC3 fixed-point decoder for MIPS platforms
33 * This file is part of FFmpeg.
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.
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.
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
52 #define FFT_FIXED_32 1
57 * Table for center mix levels
58 * reference: Section 5.4.2.4 cmixlev
60 static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
63 * Table for surround mix levels
64 * reference: Section 5.4.2.5 surmixlev
66 static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
68 int end_freq_inv_tab[8] =
70 50529027, 44278013, 39403370, 32292987, 27356480, 23729101, 20951060, 18755316
73 static void scale_coefs (
81 int temp, temp1, temp2, temp3, temp4, temp5, temp6, temp7;
83 mul = (dynrng & 0x1f) + 0x20;
84 shift = 4 - ((dynrng << 24) >> 29);
85 round = 1 << (shift-1);
86 for (i=0; i<len; i+=8) {
89 temp1 = src[i+1] * mul;
91 temp2 = src[i+2] * mul;
93 temp1 = temp1 + round;
94 dst[i] = temp >> shift;
95 temp3 = src[i+3] * mul;
96 temp2 = temp2 + round;
98 dst[i+1] = temp1 >> shift;
99 temp4 = src[i + 4] * mul;
100 temp3 = temp3 + round;
101 dst[i+2] = temp2 >> shift;
103 temp5 = src[i+5] * mul;
104 temp4 = temp4 + round;
105 dst[i+3] = temp3 >> shift;
106 temp6 = src[i+6] * mul;
108 dst[i+4] = temp4 >> shift;
109 temp5 = temp5 + round;
110 temp7 = src[i+7] * mul;
111 temp6 = temp6 + round;
113 dst[i+5] = temp5 >> shift;
114 temp7 = temp7 + round;
115 dst[i+6] = temp6 >> shift;
116 dst[i+7] = temp7 >> shift;
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).
125 static void ac3_downmix_c_fixed16(int16_t **samples, int16_t (*matrix)[2],
126 int out_ch, int in_ch, int len)
131 for (i = 0; i < len; i++) {
133 for (j = 0; j < in_ch; j++) {
134 v0 += samples[j][i] * matrix[j][0];
135 v1 += samples[j][i] * matrix[j][1];
137 samples[0][i] = (v0+2048)>>12;
138 samples[1][i] = (v1+2048)>>12;
140 } else if (out_ch == 1) {
141 for (i = 0; i < len; i++) {
143 for (j = 0; j < in_ch; j++)
144 v0 += samples[j][i] * matrix[j][0];
145 samples[0][i] = (v0+2048)>>12;
152 static const AVOption options[] = {
156 static const AVClass ac3_decoder_class = {
157 .class_name = "Fixed-Point AC-3 Decoder",
158 .item_name = av_default_item_name,
160 .version = LIBAVUTIL_VERSION_INT,
163 AVCodec ff_ac3_fixed_decoder = {
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,