1 /*
2 * Real Audio 1.0 (14.4K)
3 *
4 * Copyright (c) 2008 Vitor Sessak
5 * Copyright (c) 2003 Nick Kurshev
6 * Based on public domain decoder at http://www.honeypot.net/audio
7 *
8 * This file is part of FFmpeg.
9 *
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 #include "libavutil/channel_layout.h"
26 #include "avcodec.h"
27 #include "get_bits.h"
28 #include "internal.h"
29 #include "ra144.h"
30
31
ra144_decode_init(AVCodecContext * avctx)32 static av_cold int ra144_decode_init(AVCodecContext * avctx)
33 {
34 RA144Context *ractx = avctx->priv_data;
35
36 ractx->avctx = avctx;
37 ff_audiodsp_init(&ractx->adsp);
38
39 ractx->lpc_coef[0] = ractx->lpc_tables[0];
40 ractx->lpc_coef[1] = ractx->lpc_tables[1];
41
42 avctx->channels = 1;
43 avctx->channel_layout = AV_CH_LAYOUT_MONO;
44 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
45
46 return 0;
47 }
48
do_output_subblock(RA144Context * ractx,const int16_t * lpc_coefs,int gval,GetBitContext * gb)49 static void do_output_subblock(RA144Context *ractx, const int16_t *lpc_coefs,
50 int gval, GetBitContext *gb)
51 {
52 int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
53 int gain = get_bits(gb, 8);
54 int cb1_idx = get_bits(gb, 7);
55 int cb2_idx = get_bits(gb, 7);
56
57 ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval,
58 gain);
59 }
60
61 /** Uncompress one block (20 bytes -> 160*2 bytes). */
ra144_decode_frame(AVCodecContext * avctx,void * data,int * got_frame_ptr,AVPacket * avpkt)62 static int ra144_decode_frame(AVCodecContext * avctx, void *data,
63 int *got_frame_ptr, AVPacket *avpkt)
64 {
65 AVFrame *frame = data;
66 const uint8_t *buf = avpkt->data;
67 int buf_size = avpkt->size;
68 static const uint8_t sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
69 unsigned int refl_rms[NBLOCKS]; // RMS of the reflection coefficients
70 int16_t block_coefs[NBLOCKS][LPC_ORDER]; // LPC coefficients of each sub-block
71 unsigned int lpc_refl[LPC_ORDER]; // LPC reflection coefficients of the frame
72 int i, j;
73 int ret;
74 int16_t *samples;
75 unsigned int energy;
76
77 RA144Context *ractx = avctx->priv_data;
78 GetBitContext gb;
79
80 if (buf_size < FRAME_SIZE) {
81 av_log(avctx, AV_LOG_ERROR,
82 "Frame too small (%d bytes). Truncated file?\n", buf_size);
83 *got_frame_ptr = 0;
84 return AVERROR_INVALIDDATA;
85 }
86
87 /* get output buffer */
88 frame->nb_samples = NBLOCKS * BLOCKSIZE;
89 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
90 return ret;
91 samples = (int16_t *)frame->data[0];
92
93 init_get_bits8(&gb, buf, FRAME_SIZE);
94
95 for (i = 0; i < LPC_ORDER; i++)
96 lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])];
97
98 ff_eval_coefs(ractx->lpc_coef[0], lpc_refl);
99 ractx->lpc_refl_rms[0] = ff_rms(lpc_refl);
100
101 energy = ff_energy_tab[get_bits(&gb, 5)];
102
103 refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy);
104 refl_rms[1] = ff_interp(ractx, block_coefs[1], 2,
105 energy <= ractx->old_energy,
106 ff_t_sqrt(energy*ractx->old_energy) >> 12);
107 refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy);
108 refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy);
109
110 ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]);
111
112 for (i=0; i < NBLOCKS; i++) {
113 do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb);
114
115 for (j=0; j < BLOCKSIZE; j++)
116 *samples++ = av_clip_int16(ractx->curr_sblock[j + 10] * (1 << 2));
117 }
118
119 ractx->old_energy = energy;
120 ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0];
121
122 FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]);
123
124 *got_frame_ptr = 1;
125
126 return FRAME_SIZE;
127 }
128
129 AVCodec ff_ra_144_decoder = {
130 .name = "real_144",
131 .long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),
132 .type = AVMEDIA_TYPE_AUDIO,
133 .id = AV_CODEC_ID_RA_144,
134 .priv_data_size = sizeof(RA144Context),
135 .init = ra144_decode_init,
136 .decode = ra144_decode_frame,
137 .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
138 };
139