FFmpeg  4.4
fastaudio.c
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1 /*
2  * MOFLEX Fast Audio decoder
3  * Copyright (c) 2015-2016 Florian Nouwt
4  * Copyright (c) 2017 Adib Surani
5  * Copyright (c) 2020 Paul B Mahol
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 #include "libavutil/intreadwrite.h"
25 
26 #include "avcodec.h"
27 #include "bytestream.h"
28 #include "internal.h"
29 #include "mathops.h"
30 
31 typedef struct ChannelItems {
32  float f[8];
33  float last;
34 } ChannelItems;
35 
36 typedef struct FastAudioContext {
37  float table[8][64];
38 
41 
43 {
44  FastAudioContext *s = avctx->priv_data;
45 
47 
48  for (int i = 0; i < 8; i++)
49  s->table[0][i] = (i - 159.5f) / 160.f;
50  for (int i = 0; i < 11; i++)
51  s->table[0][i + 8] = (i - 37.5f) / 40.f;
52  for (int i = 0; i < 27; i++)
53  s->table[0][i + 8 + 11] = (i - 13.f) / 20.f;
54  for (int i = 0; i < 11; i++)
55  s->table[0][i + 8 + 11 + 27] = (i + 27.5f) / 40.f;
56  for (int i = 0; i < 7; i++)
57  s->table[0][i + 8 + 11 + 27 + 11] = (i + 152.5f) / 160.f;
58 
59  memcpy(s->table[1], s->table[0], sizeof(s->table[0]));
60 
61  for (int i = 0; i < 7; i++)
62  s->table[2][i] = (i - 33.5f) / 40.f;
63  for (int i = 0; i < 25; i++)
64  s->table[2][i + 7] = (i - 13.f) / 20.f;
65 
66  for (int i = 0; i < 32; i++)
67  s->table[3][i] = -s->table[2][31 - i];
68 
69  for (int i = 0; i < 16; i++)
70  s->table[4][i] = i * 0.22f / 3.f - 0.6f;
71 
72  for (int i = 0; i < 16; i++)
73  s->table[5][i] = i * 0.20f / 3.f - 0.3f;
74 
75  for (int i = 0; i < 8; i++)
76  s->table[6][i] = i * 0.36f / 3.f - 0.4f;
77 
78  for (int i = 0; i < 8; i++)
79  s->table[7][i] = i * 0.34f / 3.f - 0.2f;
80 
81  s->ch = av_calloc(avctx->channels, sizeof(*s->ch));
82  if (!s->ch)
83  return AVERROR(ENOMEM);
84 
85  return 0;
86 }
87 
88 static int read_bits(int bits, int *ppos, unsigned *src)
89 {
90  int r, pos;
91 
92  pos = *ppos;
93  pos += bits;
94  r = src[(pos - 1) / 32] >> ((-pos) & 31);
95  *ppos = pos;
96 
97  return r & ((1 << bits) - 1);
98 }
99 
100 static const uint8_t bits[8] = { 6, 6, 5, 5, 4, 0, 3, 3, };
101 
102 static void set_sample(int i, int j, int v, float *result, int *pads, float value)
103 {
104  result[i * 64 + pads[i] + j * 3] = value * (2 * v - 7);
105 }
106 
107 static int fastaudio_decode(AVCodecContext *avctx, void *data,
108  int *got_frame, AVPacket *pkt)
109 {
110  FastAudioContext *s = avctx->priv_data;
111  GetByteContext gb;
112  AVFrame *frame = data;
113  int subframes;
114  int ret;
115 
116  subframes = pkt->size / (40 * avctx->channels);
117  frame->nb_samples = subframes * 256;
118  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
119  return ret;
120 
121  bytestream2_init(&gb, pkt->data, pkt->size);
122 
123  for (int subframe = 0; subframe < subframes; subframe++) {
124  for (int channel = 0; channel < avctx->channels; channel++) {
125  ChannelItems *ch = &s->ch[channel];
126  float result[256] = { 0 };
127  unsigned src[10];
128  int inds[4], pads[4];
129  float m[8];
130  int pos = 0;
131 
132  for (int i = 0; i < 10; i++)
133  src[i] = bytestream2_get_le32(&gb);
134 
135  for (int i = 0; i < 8; i++)
136  m[7 - i] = s->table[i][read_bits(bits[i], &pos, src)];
137 
138  for (int i = 0; i < 4; i++)
139  inds[3 - i] = read_bits(6, &pos, src);
140 
141  for (int i = 0; i < 4; i++)
142  pads[3 - i] = read_bits(2, &pos, src);
143 
144  for (int i = 0, index5 = 0; i < 4; i++) {
145  float value = av_int2float((inds[i] + 1) << 20) * powf(2.f, 116.f);
146 
147  for (int j = 0, tmp = 0; j < 21; j++) {
148  set_sample(i, j, j == 20 ? tmp / 2 : read_bits(3, &pos, src), result, pads, value);
149  if (j % 10 == 9)
150  tmp = 4 * tmp + read_bits(2, &pos, src);
151  if (j == 20)
152  index5 = FFMIN(2 * index5 + tmp % 2, 63);
153  }
154 
155  m[2] = s->table[5][index5];
156  }
157 
158  for (int i = 0; i < 256; i++) {
159  float x = result[i];
160 
161  for (int j = 0; j < 8; j++) {
162  x -= m[j] * ch->f[j];
163  ch->f[j] += m[j] * x;
164  }
165 
166  memmove(&ch->f[0], &ch->f[1], sizeof(float) * 7);
167  ch->f[7] = x;
168  ch->last = x + ch->last * 0.86f;
169  result[i] = ch->last * 2.f;
170  }
171 
172  memcpy(frame->extended_data[channel] + 1024 * subframe, result, 256 * sizeof(float));
173  }
174  }
175 
176  *got_frame = 1;
177 
178  return pkt->size;
179 }
180 
182 {
183  FastAudioContext *s = avctx->priv_data;
184 
185  av_freep(&s->ch);
186 
187  return 0;
188 }
189 
191  .name = "fastaudio",
192  .long_name = NULL_IF_CONFIG_SMALL("MobiClip FastAudio"),
193  .type = AVMEDIA_TYPE_AUDIO,
194  .id = AV_CODEC_ID_FASTAUDIO,
195  .priv_data_size = sizeof(FastAudioContext),
196  .init = fastaudio_init,
198  .close = fastaudio_close,
199  .capabilities = AV_CODEC_CAP_DR1,
200  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
202 };
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:925
#define av_cold
Definition: attributes.h:88
uint8_t
Libavcodec external API header.
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
#define s(width, name)
Definition: cbs_vp9.c:257
#define FFMIN(a, b)
Definition: common.h:105
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1893
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
static AVFrame * frame
channel
Use these values when setting the channel map with ebur128_set_channel().
Definition: ebur128.h:39
double value
Definition: eval.c:98
static av_cold int fastaudio_init(AVCodecContext *avctx)
Definition: fastaudio.c:42
static void set_sample(int i, int j, int v, float *result, int *pads, float value)
Definition: fastaudio.c:102
AVCodec ff_fastaudio_decoder
Definition: fastaudio.c:190
static const uint8_t bits[8]
Definition: fastaudio.c:100
static int fastaudio_decode(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *pkt)
Definition: fastaudio.c:107
static int read_bits(int bits, int *ppos, unsigned *src)
Definition: fastaudio.c:88
static av_cold int fastaudio_close(AVCodecContext *avctx)
Definition: fastaudio.c:181
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
@ AV_CODEC_ID_FASTAUDIO
Definition: codec_id.h:519
#define AVERROR(e)
Definition: error.h:43
void * av_calloc(size_t nmemb, size_t size)
Non-inlined equivalent of av_mallocz_array().
Definition: mem.c:245
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:69
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
for(j=16;j >0;--j)
int i
Definition: input.c:407
static av_always_inline float av_int2float(uint32_t i)
Reinterpret a 32-bit integer as a float.
Definition: intfloat.h:40
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
#define powf(x, y)
Definition: libm.h:50
const char data[16]
Definition: mxf.c:142
unsigned int pos
Definition: spdifenc.c:412
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
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 ** extended_data
pointers to the data planes/channels.
Definition: frame.h:365
This structure stores compressed data.
Definition: packet.h:346
int size
Definition: packet.h:370
uint8_t * data
Definition: packet.h:369
float last
Definition: fastaudio.c:33
float f[8]
Definition: fastaudio.c:32
float table[8][64]
Definition: fastaudio.c:37
ChannelItems * ch
Definition: fastaudio.c:39
#define av_freep(p)
static uint8_t tmp[11]
Definition: aes_ctr.c:27
#define src
Definition: vp8dsp.c:255
AVPacket * pkt
Definition: movenc.c:59
const char * r
Definition: vf_curves.c:116