g722dec.c
Go to the documentation of this file.
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 
37 #include "avcodec.h"
38 #include "internal.h"
39 #include "get_bits.h"
40 #include "g722.h"
41 #include "libavutil/opt.h"
42 
43 #define OFFSET(x) offsetof(G722Context, x)
44 #define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM
45 static const AVOption options[] = {
46  { "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_FLAGS, { 8 }, 6, 8, AD },
47  { NULL }
48 };
49 
50 static const AVClass g722_decoder_class = {
51  .class_name = "g722 decoder",
52  .item_name = av_default_item_name,
53  .option = options,
54  .version = LIBAVUTIL_VERSION_INT,
55 };
56 
58 {
59  G722Context *c = avctx->priv_data;
60 
61  if (avctx->channels != 1) {
62  av_log(avctx, AV_LOG_ERROR, "Only mono tracks are allowed.\n");
63  return AVERROR_INVALIDDATA;
64  }
66 
67  c->band[0].scale_factor = 8;
68  c->band[1].scale_factor = 2;
69  c->prev_samples_pos = 22;
70 
72  avctx->coded_frame = &c->frame;
73 
74  return 0;
75 }
76 
77 static const int16_t low_inv_quant5[32] = {
78  -35, -35, -2919, -2195, -1765, -1458, -1219, -1023,
79  -858, -714, -587, -473, -370, -276, -190, -110,
80  2919, 2195, 1765, 1458, 1219, 1023, 858, 714,
81  587, 473, 370, 276, 190, 110, 35, -35
82 };
83 
84 static const int16_t *low_inv_quants[3] = { ff_g722_low_inv_quant6,
87 
88 static int g722_decode_frame(AVCodecContext *avctx, void *data,
89  int *got_frame_ptr, AVPacket *avpkt)
90 {
91  G722Context *c = avctx->priv_data;
92  int16_t *out_buf;
93  int j, ret;
94  const int skip = 8 - c->bits_per_codeword;
95  const int16_t *quantizer_table = low_inv_quants[skip];
96  GetBitContext gb;
97 
98  /* get output buffer */
99  c->frame.nb_samples = avpkt->size * 2;
100  if ((ret = ff_get_buffer(avctx, &c->frame)) < 0) {
101  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
102  return ret;
103  }
104  out_buf = (int16_t *)c->frame.data[0];
105 
106  init_get_bits(&gb, avpkt->data, avpkt->size * 8);
107 
108  for (j = 0; j < avpkt->size; j++) {
109  int ilow, ihigh, rlow, rhigh, dhigh;
110  int xout1, xout2;
111 
112  ihigh = get_bits(&gb, 2);
113  ilow = get_bits(&gb, 6 - skip);
114  skip_bits(&gb, skip);
115 
116  rlow = av_clip((c->band[0].scale_factor * quantizer_table[ilow] >> 10)
117  + c->band[0].s_predictor, -16384, 16383);
118 
119  ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip));
120 
121  dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10;
122  rhigh = av_clip(dhigh + c->band[1].s_predictor, -16384, 16383);
123 
124  ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh);
125 
126  c->prev_samples[c->prev_samples_pos++] = rlow + rhigh;
127  c->prev_samples[c->prev_samples_pos++] = rlow - rhigh;
129  &xout1, &xout2);
130  *out_buf++ = av_clip_int16(xout1 >> 11);
131  *out_buf++ = av_clip_int16(xout2 >> 11);
133  memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22,
134  22 * sizeof(c->prev_samples[0]));
135  c->prev_samples_pos = 22;
136  }
137  }
138 
139  *got_frame_ptr = 1;
140  *(AVFrame *)data = c->frame;
141 
142  return avpkt->size;
143 }
144 
146  .name = "g722",
147  .type = AVMEDIA_TYPE_AUDIO,
148  .id = CODEC_ID_ADPCM_G722,
149  .priv_data_size = sizeof(G722Context),
152  .capabilities = CODEC_CAP_DR1,
153  .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
154  .priv_class = &g722_decoder_class,
155 };