lavc: add a wrapper for AVCodecContext.get_buffer().
[libav.git] / libavcodec / g722dec.c
1 /*
2 * Copyright (c) CMU 1993 Computer Science, Speech Group
3 * Chengxiang Lu and Alex Hauptmann
4 * Copyright (c) 2005 Steve Underwood <steveu at coppice.org>
5 * Copyright (c) 2009 Kenan Gillet
6 * Copyright (c) 2010 Martin Storsjo
7 *
8 * This file is part of Libav.
9 *
10 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 /**
26 * @file
27 * G.722 ADPCM audio decoder
28 *
29 * This G.722 decoder is a bit-exact implementation of the ITU G.722
30 * specification for all three specified bitrates - 64000bps, 56000bps
31 * and 48000bps. It passes the ITU tests.
32 *
33 * @note For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits
34 * respectively of each byte are ignored.
35 */
36
37 #include "libavutil/channel_layout.h"
38 #include "libavutil/opt.h"
39 #include "avcodec.h"
40 #include "get_bits.h"
41 #include "g722.h"
42 #include "internal.h"
43
44 #define OFFSET(x) offsetof(G722Context, x)
45 #define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM
46 static const AVOption options[] = {
47 { "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_FLAGS, { .i64 = 8 }, 6, 8, AD },
48 { NULL }
49 };
50
51 static const AVClass g722_decoder_class = {
52 .class_name = "g722 decoder",
53 .item_name = av_default_item_name,
54 .option = options,
55 .version = LIBAVUTIL_VERSION_INT,
56 };
57
58 static av_cold int g722_decode_init(AVCodecContext * avctx)
59 {
60 G722Context *c = avctx->priv_data;
61
62 avctx->channels = 1;
63 avctx->channel_layout = AV_CH_LAYOUT_MONO;
64 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
65
66 c->band[0].scale_factor = 8;
67 c->band[1].scale_factor = 2;
68 c->prev_samples_pos = 22;
69
70 avcodec_get_frame_defaults(&c->frame);
71 avctx->coded_frame = &c->frame;
72
73 return 0;
74 }
75
76 static const int16_t low_inv_quant5[32] = {
77 -35, -35, -2919, -2195, -1765, -1458, -1219, -1023,
78 -858, -714, -587, -473, -370, -276, -190, -110,
79 2919, 2195, 1765, 1458, 1219, 1023, 858, 714,
80 587, 473, 370, 276, 190, 110, 35, -35
81 };
82
83 static const int16_t *low_inv_quants[3] = { ff_g722_low_inv_quant6,
84 low_inv_quant5,
85 ff_g722_low_inv_quant4 };
86
87 static int g722_decode_frame(AVCodecContext *avctx, void *data,
88 int *got_frame_ptr, AVPacket *avpkt)
89 {
90 G722Context *c = avctx->priv_data;
91 int16_t *out_buf;
92 int j, ret;
93 const int skip = 8 - c->bits_per_codeword;
94 const int16_t *quantizer_table = low_inv_quants[skip];
95 GetBitContext gb;
96
97 /* get output buffer */
98 c->frame.nb_samples = avpkt->size * 2;
99 if ((ret = ff_get_buffer(avctx, &c->frame)) < 0) {
100 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
101 return ret;
102 }
103 out_buf = (int16_t *)c->frame.data[0];
104
105 init_get_bits(&gb, avpkt->data, avpkt->size * 8);
106
107 for (j = 0; j < avpkt->size; j++) {
108 int ilow, ihigh, rlow, rhigh, dhigh;
109 int xout1, xout2;
110
111 ihigh = get_bits(&gb, 2);
112 ilow = get_bits(&gb, 6 - skip);
113 skip_bits(&gb, skip);
114
115 rlow = av_clip((c->band[0].scale_factor * quantizer_table[ilow] >> 10)
116 + c->band[0].s_predictor, -16384, 16383);
117
118 ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip));
119
120 dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10;
121 rhigh = av_clip(dhigh + c->band[1].s_predictor, -16384, 16383);
122
123 ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh);
124
125 c->prev_samples[c->prev_samples_pos++] = rlow + rhigh;
126 c->prev_samples[c->prev_samples_pos++] = rlow - rhigh;
127 ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24,
128 &xout1, &xout2);
129 *out_buf++ = av_clip_int16(xout1 >> 11);
130 *out_buf++ = av_clip_int16(xout2 >> 11);
131 if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) {
132 memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22,
133 22 * sizeof(c->prev_samples[0]));
134 c->prev_samples_pos = 22;
135 }
136 }
137
138 *got_frame_ptr = 1;
139 *(AVFrame *)data = c->frame;
140
141 return avpkt->size;
142 }
143
144 AVCodec ff_adpcm_g722_decoder = {
145 .name = "g722",
146 .type = AVMEDIA_TYPE_AUDIO,
147 .id = AV_CODEC_ID_ADPCM_G722,
148 .priv_data_size = sizeof(G722Context),
149 .init = g722_decode_init,
150 .decode = g722_decode_frame,
151 .capabilities = CODEC_CAP_DR1,
152 .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
153 .priv_class = &g722_decoder_class,
154 };