3 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
5 * This file is part of Libav.
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
29 #include "gsmdec_data.h"
31 static void apcm_dequant_add(GetBitContext *gb, int16_t *dst)
34 int maxidx = get_bits(gb, 6);
35 const int16_t *tab = ff_gsm_dequant_tab[maxidx];
36 for (i = 0; i < 13; i++)
37 dst[3*i] += tab[get_bits(gb, 3)];
40 static inline int gsm_mult(int a, int b)
42 return (a * b + (1 << 14)) >> 15;
45 static void long_term_synth(int16_t *dst, int lag, int gain_idx)
48 const int16_t *src = dst - lag;
49 uint16_t gain = ff_gsm_long_term_gain_tab[gain_idx];
50 for (i = 0; i < 40; i++)
51 dst[i] = gsm_mult(gain, src[i]);
54 static inline int decode_log_area(int coded, int factor, int offset)
58 return gsm_mult(coded, factor) << 1;
61 static av_noinline int get_rrp(int filtered)
63 int abs = FFABS(filtered);
64 if (abs < 11059) abs <<= 1;
65 else if (abs < 20070) abs += 11059;
66 else abs = (abs >> 2) + 26112;
67 return filtered < 0 ? -abs : abs;
70 static int filter_value(int in, int rrp[8], int v[9])
73 for (i = 7; i >= 0; i--) {
74 in -= gsm_mult(rrp[i], v[i]);
75 v[i + 1] = v[i] + gsm_mult(rrp[i], in);
81 static void short_term_synth(GSMContext *ctx, int16_t *dst, const int16_t *src)
85 int *lar = ctx->lar[ctx->lar_idx];
86 int *lar_prev = ctx->lar[ctx->lar_idx ^ 1];
87 for (i = 0; i < 8; i++)
88 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar_prev[i] >> 1) + (lar[i] >> 2));
89 for (i = 0; i < 13; i++)
90 dst[i] = filter_value(src[i], rrp, ctx->v);
92 for (i = 0; i < 8; i++)
93 rrp[i] = get_rrp((lar_prev[i] >> 1) + (lar [i] >> 1));
94 for (i = 13; i < 27; i++)
95 dst[i] = filter_value(src[i], rrp, ctx->v);
97 for (i = 0; i < 8; i++)
98 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar [i] >> 1) + (lar[i] >> 2));
99 for (i = 27; i < 40; i++)
100 dst[i] = filter_value(src[i], rrp, ctx->v);
102 for (i = 0; i < 8; i++)
103 rrp[i] = get_rrp(lar[i]);
104 for (i = 40; i < 160; i++)
105 dst[i] = filter_value(src[i], rrp, ctx->v);
110 static int postprocess(int16_t *data, int msr)
113 for (i = 0; i < 160; i++) {
114 msr = av_clip_int16(data[i] + gsm_mult(msr, 28180));
115 data[i] = av_clip_int16(msr << 1) & ~7;
120 static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples,
123 GSMContext *ctx = avctx->priv_data;
125 int16_t *ref_dst = ctx->ref_buf + 120;
126 int *lar = ctx->lar[ctx->lar_idx];
127 lar[0] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
128 lar[1] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
129 lar[2] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) + 2048*2);
130 lar[3] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) - 2560*2);
131 lar[4] = decode_log_area(get_bits(gb, 4), 19223, (1 << 13) + 94*2);
132 lar[5] = decode_log_area(get_bits(gb, 4), 17476, (1 << 13) - 1792*2);
133 lar[6] = decode_log_area(get_bits(gb, 3), 31454, (1 << 12) - 341*2);
134 lar[7] = decode_log_area(get_bits(gb, 3), 29708, (1 << 12) - 1144*2);
136 for (i = 0; i < 4; i++) {
137 int lag = get_bits(gb, 7);
138 int gain_idx = get_bits(gb, 2);
139 int offset = get_bits(gb, 2);
140 lag = av_clip(lag, 40, 120);
141 long_term_synth(ref_dst, lag, gain_idx);
142 apcm_dequant_add(gb, ref_dst + offset);
145 memcpy(ctx->ref_buf, ctx->ref_buf + 160, 120 * sizeof(*ctx->ref_buf));
146 short_term_synth(ctx, samples, ctx->ref_buf + 120);
147 // for optimal speed this could be merged with short_term_synth,
148 // not done yet because it is a bit ugly
149 ctx->msr = postprocess(samples, ctx->msr);