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g722dec.c
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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 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 /**
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 
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_INT, { .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 
59 {
60  G722Context *c = avctx->priv_data;
61 
62  avctx->channels = 1;
65 
66  c->band[0].scale_factor = 8;
67  c->band[1].scale_factor = 2;
68  c->prev_samples_pos = 22;
69 
70  ff_g722dsp_init(&c->dsp);
71 
72  return 0;
73 }
74 
75 static const int16_t low_inv_quant5[32] = {
76  -35, -35, -2919, -2195, -1765, -1458, -1219, -1023,
77  -858, -714, -587, -473, -370, -276, -190, -110,
78  2919, 2195, 1765, 1458, 1219, 1023, 858, 714,
79  587, 473, 370, 276, 190, 110, 35, -35
80 };
81 
82 static const int16_t * const low_inv_quants[3] = { ff_g722_low_inv_quant6,
85 
86 static int g722_decode_frame(AVCodecContext *avctx, void *data,
87  int *got_frame_ptr, AVPacket *avpkt)
88 {
89  G722Context *c = avctx->priv_data;
90  AVFrame *frame = 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  frame->nb_samples = avpkt->size * 2;
99  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
100  return ret;
101  out_buf = (int16_t *)frame->data[0];
102 
103  init_get_bits(&gb, avpkt->data, avpkt->size * 8);
104 
105  for (j = 0; j < avpkt->size; j++) {
106  int ilow, ihigh, rlow, rhigh, dhigh;
107  int xout[2];
108 
109  ihigh = get_bits(&gb, 2);
110  ilow = get_bits(&gb, 6 - skip);
111  skip_bits(&gb, skip);
112 
113  rlow = av_clip_intp2((c->band[0].scale_factor * quantizer_table[ilow] >> 10)
114  + c->band[0].s_predictor, 14);
115 
116  ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip));
117 
118  dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10;
119  rhigh = av_clip_intp2(dhigh + c->band[1].s_predictor, 14);
120 
121  ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh);
122 
123  c->prev_samples[c->prev_samples_pos++] = rlow + rhigh;
124  c->prev_samples[c->prev_samples_pos++] = rlow - rhigh;
125  c->dsp.apply_qmf(c->prev_samples + c->prev_samples_pos - 24, xout);
126  *out_buf++ = av_clip_int16(xout[0] >> 11);
127  *out_buf++ = av_clip_int16(xout[1] >> 11);
129  memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22,
130  22 * sizeof(c->prev_samples[0]));
131  c->prev_samples_pos = 22;
132  }
133  }
134 
135  *got_frame_ptr = 1;
136 
137  return avpkt->size;
138 }
139 
141  .name = "g722",
142  .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
143  .type = AVMEDIA_TYPE_AUDIO,
145  .priv_data_size = sizeof(G722Context),
148  .capabilities = AV_CODEC_CAP_DR1,
149  .priv_class = &g722_decoder_class,
150 };
#define OFFSET(x)
Definition: g722dec.c:44
#define NULL
Definition: coverity.c:32
const int16_t ff_g722_low_inv_quant4[16]
Definition: g722.c:59
This structure describes decoded (raw) audio or video data.
Definition: frame.h:184
AVOption.
Definition: opt.h:245
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
void(* apply_qmf)(const int16_t *prev_samples, int xout[2])
Definition: g722dsp.h:27
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:247
#define LIBAVUTIL_VERSION_INT
Definition: version.h:70
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
AVCodec ff_adpcm_g722_decoder
Definition: g722dec.c:140
int size
Definition: avcodec.h:1580
static av_cold int g722_decode_init(AVCodecContext *avctx)
Definition: g722dec.c:58
AVCodec.
Definition: avcodec.h:3541
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:2417
#define av_cold
Definition: attributes.h:82
AVOptions.
#define PREV_SAMPLES_BUF_SIZE
Definition: g722.h:32
static AVFrame * frame
uint8_t * data
Definition: avcodec.h:1579
bitstream reader API header.
static const AVClass g722_decoder_class
Definition: g722dec.c:51
av_default_item_name
int bits_per_codeword
Definition: g722.h:36
const int16_t ff_g722_low_inv_quant6[64]
Definition: g722.c:63
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
int16_t prev_samples[PREV_SAMPLES_BUF_SIZE]
memory of past decoded samples
Definition: g722.h:37
const char * name
Name of the codec implementation.
Definition: avcodec.h:3548
av_cold void ff_g722dsp_init(G722DSPContext *c)
Definition: g722dsp.c:68
static const int16_t *const low_inv_quants[3]
Definition: g722dec.c:82
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2460
struct G722Context::G722Band band[2]
audio channel layout utility functions
static const AVOption options[]
Definition: g722dec.c:46
void ff_g722_update_low_predictor(struct G722Band *band, const int ilow)
Definition: g722.c:143
static const int16_t low_inv_quant5[32]
Definition: g722dec.c:75
G722DSPContext dsp
Definition: g722.h:66
Libavcodec external API header.
#define AD
Definition: g722dec.c:45
main external API structure.
Definition: avcodec.h:1648
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:928
Describe the class of an AVClass context structure.
Definition: log.h:67
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:292
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:406
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:198
static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt)
Definition: ccaption_dec.c:722
common internal api header.
signed 16 bits
Definition: samplefmt.h:61
static double c[64]
int prev_samples_pos
the number of values in prev_samples
Definition: g722.h:38
void * priv_data
Definition: avcodec.h:1690
static int g722_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: g722dec.c:86
const int16_t ff_g722_high_inv_quant[4]
Definition: g722.c:51
int channels
number of audio channels
Definition: avcodec.h:2410
int16_t s_predictor
predictor output value
Definition: g722.h:44
void ff_g722_update_high_predictor(struct G722Band *band, const int dhigh, const int ihigh)
Definition: g722.c:154
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1556
int16_t scale_factor
delayed quantizer scale factor
Definition: g722.h:52
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:241
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:955