FFmpeg
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  */
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 
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;
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 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
void(* mdct_end)(struct AC3EncodeContext *s)
Definition: ac3enc.h:257
av_cold void ff_kbd_window_init(float *window, float alpha, int n)
Generate a Kaiser-Bessel Derived Window.
Definition: kbdwin.c:26
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
static int allocate_sample_buffers(AC3EncodeContext *s)
const AVOption ff_ac3_enc_options[]
Definition: ac3enc.c:77
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
Definition: ac3enc_fixed.c:119
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
#define COEF_MIN
Definition: ac3enc.h:60
int(* mdct_init)(struct AC3EncodeContext *s)
Definition: ac3enc.h:258
AVCodec.
Definition: codec.h:197
static av_cold int ac3_fixed_mdct_init(AC3EncodeContext *s)
Initialize MDCT tables.
Definition: ac3enc_fixed.c:97
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
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
#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 av_cold
Definition: attributes.h:88
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
Finalize encoding and free any memory allocated by the encoder.
Definition: ac3enc.c:2115
AVFixedDSPContext * fdsp
Definition: ac3enc.h:163
#define lrintf(x)
Definition: libm_mips.h:70
const AVCodecDefault ff_ac3_enc_defaults[]
Definition: ac3enc.c:127
AC3DSPContext ac3dsp
AC-3 optimized functions.
Definition: ac3enc.h:166
#define ff_sqrt
Definition: mathops.h:206
int64_t CoefSumType
Definition: ac3enc.h:65
const uint64_t ff_ac3_channel_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:142
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:117
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:616
const char * name
Name of the codec implementation.
Definition: codec.h:204
int fixed_point
indicates if fixed-point encoder is being used
Definition: ac3enc.h:172
#define ff_mdct_init
Definition: fft.h:161
#define AC3_BLOCK_SIZE
Definition: ac3.h:35
static av_cold void ac3_fixed_mdct_end(AC3EncodeContext *s)
Finalize MDCT and free allocated memory.
Definition: ac3enc_fixed.c:86
#define AV_CODEC_FLAG_BITEXACT
Use only bitexact stuff (except (I)DCT).
Definition: avcodec.h:333
#define FFMIN(a, b)
Definition: common.h:105
AudioDSPContext adsp
Definition: ac3enc.h:159
signed 32 bits, planar
Definition: samplefmt.h:68
int32_t
#define s(width, name)
Definition: cbs_vp9.c:257
FFTContext mdct
FFT context for MDCT calculation.
Definition: ac3enc.h:167
const SampleType * mdct_window
MDCT window function array.
Definition: ac3enc.h:168
void(* sum_square_butterfly_int32)(int64_t sum[4], const int32_t *coef0, const int32_t *coef1, int len)
Definition: ac3dsp.h:96
static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef, unsigned int len)
Definition: ac3enc_fixed.c:55
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
Definition: ac3enc_fixed.c:65
main external API structure.
Definition: avcodec.h:536
int(* allocate_sample_buffers)(struct AC3EncodeContext *s)
Definition: ac3enc.h:261
Describe the class of an AVClass context structure.
Definition: log.h:67
int ff_ac3_fixed_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
AC-3 encoder private context.
Definition: ac3enc.h:154
AVFixedDSPContext * avpriv_alloc_fixed_dsp(int bit_exact)
Allocate and initialize a fixed DSP context.
Definition: fixed_dsp.c:149
#define COEF_MAX
Definition: ac3enc.h:61
AC-3 encoder float/fixed template.
common internal api header.
AVCodec ff_ac3_fixed_encoder
Definition: ac3enc_fixed.c:130
#define ff_mdct_end
Definition: fft.h:162
static const AVClass ac3enc_class
Definition: ac3enc_fixed.c:38
AVCodecContext * avctx
parent AVCodecContext
Definition: ac3enc.h:157
void * priv_data
Definition: avcodec.h:563
int len
AC-3 encoder & E-AC-3 encoder common header.
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:941
const int ff_ac3_sample_rate_tab[]
Definition: ac3tab.c:111
#define av_malloc_array(a, b)
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
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
int32_t CoefType
Definition: ac3enc.h:64
E-AC-3 encoder.
int i
Definition: input.c:407
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
Definition: ac3enc.c:2508