FFmpeg  4.4.4
ac3enc_fixed.c
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1 /*
2  * The simplest AC-3 encoder
3  * Copyright (c) 2000 Fabrice Bellard
4  * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
5  * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
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 /**
25  * @file
26  * fixed-point AC-3 encoder.
27  */
28 
29 #define AC3ENC_FLOAT 0
30 #define FFT_FLOAT 0
31 #define FFT_FIXED_32 1
32 #include "internal.h"
33 #include "audiodsp.h"
34 #include "ac3enc.h"
35 #include "eac3enc.h"
36 #include "kbdwin.h"
37 
38 static const AVClass ac3enc_class = {
39  .class_name = "Fixed-Point AC-3 Encoder",
40  .item_name = av_default_item_name,
41  .option = ff_ac3_enc_options,
42  .version = LIBAVUTIL_VERSION_INT,
43 };
44 
45 static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4],
46  const int32_t *coef0, const int32_t *coef1,
47  int len)
48 {
49  s->ac3dsp.sum_square_butterfly_int32(sum, coef0, coef1, len);
50 }
51 
52 /*
53  * Clip MDCT coefficients to allowable range.
54  */
55 static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef,
56  unsigned int len)
57 {
58  adsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len);
59 }
60 
61 
62 /*
63  * Calculate a single coupling coordinate.
64  */
65 static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
66 {
67  if (energy_cpl <= COEF_MAX) {
68  return 1048576;
69  } else {
70  uint64_t coord = energy_ch / (energy_cpl >> 24);
71  uint32_t coord32 = FFMIN(coord, 1073741824);
72  coord32 = ff_sqrt(coord32) << 9;
73  return FFMIN(coord32, COEF_MAX);
74  }
75 }
76 
77 
78 #include "ac3enc_template.c"
79 
80 
81 /**
82  * Finalize MDCT and free allocated memory.
83  *
84  * @param s AC-3 encoder private context
85  */
87 {
88  ff_mdct_end(&s->mdct);
89 }
90 
91 /**
92  * Initialize MDCT tables.
93  *
94  * @param s AC-3 encoder private context
95  * @return 0 on success, negative error code on failure
96  */
98 {
99  float fwin[AC3_BLOCK_SIZE];
100 
101  int32_t *iwin = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*iwin));
102  if (!iwin)
103  return AVERROR(ENOMEM);
104 
106  for (int i = 0; i < AC3_BLOCK_SIZE; i++)
107  iwin[i] = lrintf(fwin[i] * (1 << 22));
108 
109  s->mdct_window = iwin;
110 
111  s->fdsp = avpriv_alloc_fixed_dsp(s->avctx->flags & AV_CODEC_FLAG_BITEXACT);
112  if (!s->fdsp)
113  return AVERROR(ENOMEM);
114 
115  return ff_mdct_init(&s->mdct, 9, 0, -1.0);
116 }
117 
118 
120 {
121  AC3EncodeContext *s = avctx->priv_data;
122  s->fixed_point = 1;
123  s->mdct_end = ac3_fixed_mdct_end;
124  s->mdct_init = ac3_fixed_mdct_init;
125  s->allocate_sample_buffers = allocate_sample_buffers;
126  return ff_ac3_encode_init(avctx);
127 }
128 
129 
131  .name = "ac3_fixed",
132  .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
133  .type = AVMEDIA_TYPE_AUDIO,
134  .id = AV_CODEC_ID_AC3,
135  .priv_data_size = sizeof(AC3EncodeContext),
137  .encode2 = ff_ac3_fixed_encode_frame,
138  .close = ff_ac3_encode_close,
139  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32P,
141  .priv_class = &ac3enc_class,
143  .supported_samplerates = ff_ac3_sample_rate_tab,
144  .channel_layouts = ff_ac3_channel_layouts,
145  .defaults = ff_ac3_enc_defaults,
146 };
#define AC3_BLOCK_SIZE
Definition: ac3.h:35
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
Finalize encoding and free any memory allocated by the encoder.
Definition: ac3enc.c:2113
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
Definition: ac3enc.c:2506
const AVCodecDefault ff_ac3_enc_defaults[]
Definition: ac3enc.c:127
const AVOption ff_ac3_enc_options[]
Definition: ac3enc.c:77
const uint64_t ff_ac3_channel_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:142
AC-3 encoder & E-AC-3 encoder common header.
int ff_ac3_fixed_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
#define COEF_MAX
Definition: ac3enc.h:61
#define COEF_MIN
Definition: ac3enc.h:60
int64_t CoefSumType
Definition: ac3enc.h:65
int32_t CoefType
Definition: ac3enc.h:64
static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
Definition: ac3enc_fixed.c:119
static av_cold void ac3_fixed_mdct_end(AC3EncodeContext *s)
Finalize MDCT and free allocated memory.
Definition: ac3enc_fixed.c:86
AVCodec ff_ac3_fixed_encoder
Definition: ac3enc_fixed.c:130
static const AVClass ac3enc_class
Definition: ac3enc_fixed.c:38
static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef, unsigned int len)
Definition: ac3enc_fixed.c:55
static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4], const int32_t *coef0, const int32_t *coef1, int len)
Definition: ac3enc_fixed.c:45
static av_cold int ac3_fixed_mdct_init(AC3EncodeContext *s)
Initialize MDCT tables.
Definition: ac3enc_fixed.c:97
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
Definition: ac3enc_fixed.c:65
AC-3 encoder float/fixed template.
static int allocate_sample_buffers(AC3EncodeContext *s)
const int ff_ac3_sample_rate_tab[]
Definition: ac3tab.c:111
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:925
#define av_cold
Definition: attributes.h:88
int32_t
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
#define s(width, name)
Definition: cbs_vp9.c:257
#define FFMIN(a, b)
Definition: common.h:105
E-AC-3 encoder.
#define ff_mdct_init
Definition: fft.h:161
#define ff_mdct_end
Definition: fft.h:162
#define AV_CODEC_FLAG_BITEXACT
Use only bitexact stuff (except (I)DCT).
Definition: avcodec.h:333
@ AV_CODEC_ID_AC3
Definition: codec_id.h:427
#define AVERROR(e)
Definition: error.h:43
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
@ AV_SAMPLE_FMT_S32P
signed 32 bits, planar
Definition: samplefmt.h:68
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
int i
Definition: input.c:407
av_cold void ff_kbd_window_init(float *window, float alpha, int n)
Generate a Kaiser-Bessel Derived Window.
Definition: kbdwin.c:26
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:41
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: internal.h:49
AVFixedDSPContext * avpriv_alloc_fixed_dsp(int bit_exact)
Allocate and initialize a fixed DSP context.
Definition: fixed_dsp.c:149
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 lrintf(x)
Definition: libm_mips.h:70
#define ff_sqrt
Definition: mathops.h:206
AC-3 encoder private context.
Definition: ac3enc.h:154
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
void * priv_data
Definition: avcodec.h:563
AVCodec.
Definition: codec.h:197
const char * name
Name of the codec implementation.
Definition: codec.h:204
void(* vector_clip_int32)(int32_t *dst, const int32_t *src, int32_t min, int32_t max, unsigned int len)
Clip each element in an array of int32_t to a given minimum and maximum value.
Definition: audiodsp.h:46
#define av_malloc_array(a, b)
int len