3 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 #include "gsmdec_data.h"
30 static void apcm_dequant_add(GetBitContext *gb, int16_t *dst)
33 int maxidx = get_bits(gb, 6);
34 const int16_t *tab = ff_gsm_dequant_tab[maxidx];
35 for (i = 0; i < 13; i++)
36 dst[3*i] += tab[get_bits(gb, 3)];
39 static inline int gsm_mult(int a, int b)
41 return (a * b + (1 << 14)) >> 15;
44 static void long_term_synth(int16_t *dst, int lag, int gain_idx)
47 const int16_t *src = dst - lag;
48 uint16_t gain = ff_gsm_long_term_gain_tab[gain_idx];
49 for (i = 0; i < 40; i++)
50 dst[i] = gsm_mult(gain, src[i]);
53 static inline int decode_log_area(int coded, int factor, int offset)
57 return gsm_mult(coded, factor) << 1;
60 static av_noinline int get_rrp(int filtered)
62 int abs = FFABS(filtered);
63 if (abs < 11059) abs <<= 1;
64 else if (abs < 20070) abs += 11059;
65 else abs = (abs >> 2) + 26112;
66 return filtered < 0 ? -abs : abs;
69 static int filter_value(int in, int rrp[8], int v[9])
72 for (i = 7; i >= 0; i--) {
73 in -= gsm_mult(rrp[i], v[i]);
74 v[i + 1] = v[i] + gsm_mult(rrp[i], in);
80 static void short_term_synth(GSMContext *ctx, int16_t *dst, const int16_t *src)
84 int *lar = ctx->lar[ctx->lar_idx];
85 int *lar_prev = ctx->lar[ctx->lar_idx ^ 1];
86 for (i = 0; i < 8; i++)
87 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar_prev[i] >> 1) + (lar[i] >> 2));
88 for (i = 0; i < 13; i++)
89 dst[i] = filter_value(src[i], rrp, ctx->v);
91 for (i = 0; i < 8; i++)
92 rrp[i] = get_rrp((lar_prev[i] >> 1) + (lar [i] >> 1));
93 for (i = 13; i < 27; i++)
94 dst[i] = filter_value(src[i], rrp, ctx->v);
96 for (i = 0; i < 8; i++)
97 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar [i] >> 1) + (lar[i] >> 2));
98 for (i = 27; i < 40; i++)
99 dst[i] = filter_value(src[i], rrp, ctx->v);
101 for (i = 0; i < 8; i++)
102 rrp[i] = get_rrp(lar[i]);
103 for (i = 40; i < 160; i++)
104 dst[i] = filter_value(src[i], rrp, ctx->v);
109 static int postprocess(int16_t *data, int msr)
112 for (i = 0; i < 160; i++) {
113 msr = av_clip_int16(data[i] + gsm_mult(msr, 28180));
114 data[i] = av_clip_int16(msr << 1) & ~7;
119 static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples,
122 GSMContext *ctx = avctx->priv_data;
124 int16_t *ref_dst = ctx->ref_buf + 120;
125 int *lar = ctx->lar[ctx->lar_idx];
126 lar[0] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
127 lar[1] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
128 lar[2] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) + 2048*2);
129 lar[3] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) - 2560*2);
130 lar[4] = decode_log_area(get_bits(gb, 4), 19223, (1 << 13) + 94*2);
131 lar[5] = decode_log_area(get_bits(gb, 4), 17476, (1 << 13) - 1792*2);
132 lar[6] = decode_log_area(get_bits(gb, 3), 31454, (1 << 12) - 341*2);
133 lar[7] = decode_log_area(get_bits(gb, 3), 29708, (1 << 12) - 1144*2);
135 for (i = 0; i < 4; i++) {
136 int lag = get_bits(gb, 7);
137 int gain_idx = get_bits(gb, 2);
138 int offset = get_bits(gb, 2);
139 lag = av_clip(lag, 40, 120);
140 long_term_synth(ref_dst, lag, gain_idx);
141 apcm_dequant_add(gb, ref_dst + offset);
144 memcpy(ctx->ref_buf, ctx->ref_buf + 160, 120 * sizeof(*ctx->ref_buf));
145 short_term_synth(ctx, samples, ctx->ref_buf + 120);
146 // for optimal speed this could be merged with short_term_synth,
147 // not done yet because it is a bit ugly
148 ctx->msr = postprocess(samples, ctx->msr);