FFmpeg  4.4.5
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  ret = init_get_bits8(&gb, avpkt->data, avpkt->size);
104  if (ret < 0)
105  return ret;
106 
107  for (j = 0; j < avpkt->size; j++) {
108  int ilow, ihigh, rlow, rhigh, dhigh;
109  int xout[2];
110 
111  ihigh = get_bits(&gb, 2);
112  ilow = get_bits(&gb, 6 - skip);
113  skip_bits(&gb, skip);
114 
115  rlow = av_clip_intp2((c->band[0].scale_factor * quantizer_table[ilow] >> 10)
116  + c->band[0].s_predictor, 14);
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_intp2(dhigh + c->band[1].s_predictor, 14);
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  c->dsp.apply_qmf(c->prev_samples + c->prev_samples_pos - 24, xout);
128  *out_buf++ = av_clip_int16(xout[0] >> 11);
129  *out_buf++ = av_clip_int16(xout[1] >> 11);
130  if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) {
131  memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22,
132  22 * sizeof(c->prev_samples[0]));
133  c->prev_samples_pos = 22;
134  }
135  }
136 
137  *got_frame_ptr = 1;
138 
139  return avpkt->size;
140 }
141 
143  .name = "g722",
144  .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
145  .type = AVMEDIA_TYPE_AUDIO,
147  .priv_data_size = sizeof(G722Context),
151  .priv_class = &g722_decoder_class,
152 };
#define av_cold
Definition: attributes.h:88
Libavcodec external API header.
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
audio channel layout utility functions
#define av_clip_intp2
Definition: common.h:143
#define av_clip_int16
Definition: common.h:137
#define NULL
Definition: coverity.c:32
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1900
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
static AVFrame * frame
#define PREV_SAMPLES_BUF_SIZE
Definition: g722.h:32
static const AVClass g722_decoder_class
Definition: g722dec.c:51
static const int16_t *const low_inv_quants[3]
Definition: g722dec.c:82
static int g722_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: g722dec.c:86
static const int16_t low_inv_quant5[32]
Definition: g722dec.c:75
static const AVOption options[]
Definition: g722dec.c:46
static av_cold int g722_decode_init(AVCodecContext *avctx)
Definition: g722dec.c:58
AVCodec ff_adpcm_g722_decoder
Definition: g722dec.c:142
#define AD
Definition: g722dec.c:45
#define OFFSET(x)
Definition: g722dec.c:44
bitstream reader API header.
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:677
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
@ AV_OPT_TYPE_INT
Definition: opt.h:225
#define AV_CH_LAYOUT_MONO
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
#define AV_CODEC_CAP_CHANNEL_CONF
Codec should fill in channel configuration and samplerate instead of container.
Definition: codec.h:104
@ AV_CODEC_ID_ADPCM_G722
Definition: codec_id.h:381
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition: samplefmt.h:61
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
const int16_t ff_g722_low_inv_quant6[64]
Definition: g722.c:63
const int16_t ff_g722_low_inv_quant4[16]
Definition: g722.c:59
void ff_g722_update_high_predictor(struct G722Band *band, const int dhigh, const int ihigh)
Definition: g722.c:154
const int16_t ff_g722_high_inv_quant[4]
Definition: g722.c:51
void ff_g722_update_low_predictor(struct G722Band *band, const int ilow)
Definition: g722.c:143
av_cold void ff_g722dsp_init(G722DSPContext *c)
Definition: g722dsp.c:68
common internal API header
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
const char data[16]
Definition: mxf.c:142
AVOptions.
Describe the class of an AVClass context structure.
Definition: log.h:67
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
main external API structure.
Definition: avcodec.h:536
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1204
int channels
number of audio channels
Definition: avcodec.h:1197
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:1247
void * priv_data
Definition: avcodec.h:563
AVCodec.
Definition: codec.h:197
const char * name
Name of the codec implementation.
Definition: codec.h:204
This structure describes decoded (raw) audio or video data.
Definition: frame.h:318
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:384
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:332
AVOption.
Definition: opt.h:248
This structure stores compressed data.
Definition: packet.h:346
int size
Definition: packet.h:370
uint8_t * data
Definition: packet.h:369
static double c[64]