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
8 * This file is part of FFmpeg.
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.
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.
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
27 * G.722 ADPCM audio decoder
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.
33 * @note For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits
34 * respectively of each byte are ignored.
37 #include "libavutil/channel_layout.h"
38 #include "libavutil/opt.h"
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
},
51 static const AVClass g722_decoder_class
= {
52 .class_name
= "g722 decoder",
53 .item_name
= av_default_item_name
,
55 .version
= LIBAVUTIL_VERSION_INT
,
58 static av_cold
int g722_decode_init(AVCodecContext
* avctx
)
60 G722Context
*c
= avctx
->priv_data
;
63 avctx
->channel_layout
= AV_CH_LAYOUT_MONO
;
64 avctx
->sample_fmt
= AV_SAMPLE_FMT_S16
;
66 c
->band
[0].scale_factor
= 8;
67 c
->band
[1].scale_factor
= 2;
68 c
->prev_samples_pos
= 22;
73 static const int16_t low_inv_quant5
[32] = {
74 -35, -35, -2919, -2195, -1765, -1458, -1219, -1023,
75 -858, -714, -587, -473, -370, -276, -190, -110,
76 2919, 2195, 1765, 1458, 1219, 1023, 858, 714,
77 587, 473, 370, 276, 190, 110, 35, -35
80 static const int16_t * const low_inv_quants
[3] = { ff_g722_low_inv_quant6
,
82 ff_g722_low_inv_quant4
};
84 static int g722_decode_frame(AVCodecContext
*avctx
, void *data
,
85 int *got_frame_ptr
, AVPacket
*avpkt
)
87 G722Context
*c
= avctx
->priv_data
;
88 AVFrame
*frame
= data
;
91 const int skip
= 8 - c
->bits_per_codeword
;
92 const int16_t *quantizer_table
= low_inv_quants
[skip
];
95 /* get output buffer */
96 frame
->nb_samples
= avpkt
->size
* 2;
97 if ((ret
= ff_get_buffer(avctx
, frame
, 0)) < 0)
99 out_buf
= (int16_t *)frame
->data
[0];
101 init_get_bits(&gb
, avpkt
->data
, avpkt
->size
* 8);
103 for (j
= 0; j
< avpkt
->size
; j
++) {
104 int ilow
, ihigh
, rlow
, rhigh
, dhigh
;
107 ihigh
= get_bits(&gb
, 2);
108 ilow
= get_bits(&gb
, 6 - skip
);
109 skip_bits(&gb
, skip
);
111 rlow
= av_clip((c
->band
[0].scale_factor
* quantizer_table
[ilow
] >> 10)
112 + c
->band
[0].s_predictor
, -16384, 16383);
114 ff_g722_update_low_predictor(&c
->band
[0], ilow
>> (2 - skip
));
116 dhigh
= c
->band
[1].scale_factor
* ff_g722_high_inv_quant
[ihigh
] >> 10;
117 rhigh
= av_clip(dhigh
+ c
->band
[1].s_predictor
, -16384, 16383);
119 ff_g722_update_high_predictor(&c
->band
[1], dhigh
, ihigh
);
121 c
->prev_samples
[c
->prev_samples_pos
++] = rlow
+ rhigh
;
122 c
->prev_samples
[c
->prev_samples_pos
++] = rlow
- rhigh
;
123 ff_g722_apply_qmf(c
->prev_samples
+ c
->prev_samples_pos
- 24,
125 *out_buf
++ = av_clip_int16(xout1
>> 11);
126 *out_buf
++ = av_clip_int16(xout2
>> 11);
127 if (c
->prev_samples_pos
>= PREV_SAMPLES_BUF_SIZE
) {
128 memmove(c
->prev_samples
, c
->prev_samples
+ c
->prev_samples_pos
- 22,
129 22 * sizeof(c
->prev_samples
[0]));
130 c
->prev_samples_pos
= 22;
139 AVCodec ff_adpcm_g722_decoder
= {
141 .long_name
= NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
142 .type
= AVMEDIA_TYPE_AUDIO
,
143 .id
= AV_CODEC_ID_ADPCM_G722
,
144 .priv_data_size
= sizeof(G722Context
),
145 .init
= g722_decode_init
,
146 .decode
= g722_decode_frame
,
147 .capabilities
= CODEC_CAP_DR1
,
148 .priv_class
= &g722_decoder_class
,