yading@10: /* yading@10: * gsm 06.10 decoder yading@10: * Copyright (c) 2010 Reimar Döffinger yading@10: * yading@10: * This file is part of FFmpeg. yading@10: * yading@10: * FFmpeg is free software; you can redistribute it and/or yading@10: * modify it under the terms of the GNU Lesser General Public yading@10: * License as published by the Free Software Foundation; either yading@10: * version 2.1 of the License, or (at your option) any later version. yading@10: * yading@10: * FFmpeg is distributed in the hope that it will be useful, yading@10: * but WITHOUT ANY WARRANTY; without even the implied warranty of yading@10: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU yading@10: * Lesser General Public License for more details. yading@10: * yading@10: * You should have received a copy of the GNU Lesser General Public yading@10: * License along with FFmpeg; if not, write to the Free Software yading@10: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA yading@10: */ yading@10: yading@10: /** yading@10: * @file yading@10: * GSM decoder yading@10: */ yading@10: yading@10: #include "get_bits.h" yading@10: #include "gsm.h" yading@10: #include "gsmdec_data.h" yading@10: yading@10: static void apcm_dequant_add(GetBitContext *gb, int16_t *dst) yading@10: { yading@10: int i; yading@10: int maxidx = get_bits(gb, 6); yading@10: const int16_t *tab = ff_gsm_dequant_tab[maxidx]; yading@10: for (i = 0; i < 13; i++) yading@10: dst[3*i] += tab[get_bits(gb, 3)]; yading@10: } yading@10: yading@10: static inline int gsm_mult(int a, int b) yading@10: { yading@10: return (a * b + (1 << 14)) >> 15; yading@10: } yading@10: yading@10: static void long_term_synth(int16_t *dst, int lag, int gain_idx) yading@10: { yading@10: int i; yading@10: const int16_t *src = dst - lag; yading@10: uint16_t gain = ff_gsm_long_term_gain_tab[gain_idx]; yading@10: for (i = 0; i < 40; i++) yading@10: dst[i] = gsm_mult(gain, src[i]); yading@10: } yading@10: yading@10: static inline int decode_log_area(int coded, int factor, int offset) yading@10: { yading@10: coded <<= 10; yading@10: coded -= offset; yading@10: return gsm_mult(coded, factor) << 1; yading@10: } yading@10: yading@10: static av_noinline int get_rrp(int filtered) yading@10: { yading@10: int abs = FFABS(filtered); yading@10: if (abs < 11059) abs <<= 1; yading@10: else if (abs < 20070) abs += 11059; yading@10: else abs = (abs >> 2) + 26112; yading@10: return filtered < 0 ? -abs : abs; yading@10: } yading@10: yading@10: static int filter_value(int in, int rrp[8], int v[9]) yading@10: { yading@10: int i; yading@10: for (i = 7; i >= 0; i--) { yading@10: in -= gsm_mult(rrp[i], v[i]); yading@10: v[i + 1] = v[i] + gsm_mult(rrp[i], in); yading@10: } yading@10: v[0] = in; yading@10: return in; yading@10: } yading@10: yading@10: static void short_term_synth(GSMContext *ctx, int16_t *dst, const int16_t *src) yading@10: { yading@10: int i; yading@10: int rrp[8]; yading@10: int *lar = ctx->lar[ctx->lar_idx]; yading@10: int *lar_prev = ctx->lar[ctx->lar_idx ^ 1]; yading@10: for (i = 0; i < 8; i++) yading@10: rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar_prev[i] >> 1) + (lar[i] >> 2)); yading@10: for (i = 0; i < 13; i++) yading@10: dst[i] = filter_value(src[i], rrp, ctx->v); yading@10: yading@10: for (i = 0; i < 8; i++) yading@10: rrp[i] = get_rrp((lar_prev[i] >> 1) + (lar [i] >> 1)); yading@10: for (i = 13; i < 27; i++) yading@10: dst[i] = filter_value(src[i], rrp, ctx->v); yading@10: yading@10: for (i = 0; i < 8; i++) yading@10: rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar [i] >> 1) + (lar[i] >> 2)); yading@10: for (i = 27; i < 40; i++) yading@10: dst[i] = filter_value(src[i], rrp, ctx->v); yading@10: yading@10: for (i = 0; i < 8; i++) yading@10: rrp[i] = get_rrp(lar[i]); yading@10: for (i = 40; i < 160; i++) yading@10: dst[i] = filter_value(src[i], rrp, ctx->v); yading@10: yading@10: ctx->lar_idx ^= 1; yading@10: } yading@10: yading@10: static int postprocess(int16_t *data, int msr) yading@10: { yading@10: int i; yading@10: for (i = 0; i < 160; i++) { yading@10: msr = av_clip_int16(data[i] + gsm_mult(msr, 28180)); yading@10: data[i] = av_clip_int16(msr << 1) & ~7; yading@10: } yading@10: return msr; yading@10: } yading@10: yading@10: static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples, yading@10: GetBitContext *gb) yading@10: { yading@10: GSMContext *ctx = avctx->priv_data; yading@10: int i; yading@10: int16_t *ref_dst = ctx->ref_buf + 120; yading@10: int *lar = ctx->lar[ctx->lar_idx]; yading@10: lar[0] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15); yading@10: lar[1] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15); yading@10: lar[2] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) + 2048*2); yading@10: lar[3] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) - 2560*2); yading@10: lar[4] = decode_log_area(get_bits(gb, 4), 19223, (1 << 13) + 94*2); yading@10: lar[5] = decode_log_area(get_bits(gb, 4), 17476, (1 << 13) - 1792*2); yading@10: lar[6] = decode_log_area(get_bits(gb, 3), 31454, (1 << 12) - 341*2); yading@10: lar[7] = decode_log_area(get_bits(gb, 3), 29708, (1 << 12) - 1144*2); yading@10: yading@10: for (i = 0; i < 4; i++) { yading@10: int lag = get_bits(gb, 7); yading@10: int gain_idx = get_bits(gb, 2); yading@10: int offset = get_bits(gb, 2); yading@10: lag = av_clip(lag, 40, 120); yading@10: long_term_synth(ref_dst, lag, gain_idx); yading@10: apcm_dequant_add(gb, ref_dst + offset); yading@10: ref_dst += 40; yading@10: } yading@10: memcpy(ctx->ref_buf, ctx->ref_buf + 160, 120 * sizeof(*ctx->ref_buf)); yading@10: short_term_synth(ctx, samples, ctx->ref_buf + 120); yading@10: // for optimal speed this could be merged with short_term_synth, yading@10: // not done yet because it is a bit ugly yading@10: ctx->msr = postprocess(samples, ctx->msr); yading@10: return 0; yading@10: }