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 #include "audiodsp.h"
31 #include "ac3enc.h"
32 #include "codec_internal.h"
33 #include "eac3enc.h"
34 #include "kbdwin.h"
35 
36 static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4],
37  const int32_t *coef0, const int32_t *coef1,
38  int len)
39 {
40  s->ac3dsp.sum_square_butterfly_int32(sum, coef0, coef1, len);
41 }
42 
43 /*
44  * Clip MDCT coefficients to allowable range.
45  */
46 static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef,
47  unsigned int len)
48 {
49  adsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len);
50 }
51 
52 
53 /*
54  * Calculate a single coupling coordinate.
55  */
56 static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
57 {
58  if (energy_cpl <= COEF_MAX) {
59  return 1048576;
60  } else {
61  uint64_t coord = energy_ch / (energy_cpl >> 24);
62  uint32_t coord32 = FFMIN(coord, 1073741824);
63  coord32 = ff_sqrt(coord32) << 9;
64  return FFMIN(coord32, COEF_MAX);
65  }
66 }
67 
68 #include "ac3enc_template.c"
69 
70 /**
71  * Initialize MDCT tables.
72  *
73  * @param s AC-3 encoder private context
74  * @return 0 on success, negative error code on failure
75  */
77 {
78  float fwin[AC3_BLOCK_SIZE];
79  const float scale = -1.0f;
80 
81  int32_t *iwin = s->mdct_window_fixed;
82 
84  for (int i = 0; i < AC3_BLOCK_SIZE; i++)
85  iwin[i] = lrintf(fwin[i] * (1 << 22));
86 
88  if (!s->fdsp)
89  return AVERROR(ENOMEM);
90 
91  return av_tx_init(&s->tx, &s->tx_fn, AV_TX_INT32_MDCT, 0,
92  AC3_BLOCK_SIZE, &scale, 0);
93 }
94 
95 
97 {
98  AC3EncodeContext *s = avctx->priv_data;
99  int ret;
100 
101  s->fixed_point = 1;
102  s->encode_frame = encode_frame;
103 
104  ret = ac3_fixed_mdct_init(avctx, s);
105  if (ret < 0)
106  return ret;
107 
108  return ff_ac3_encode_init(avctx);
109 }
110 
111 
113  .p.name = "ac3_fixed",
114  CODEC_LONG_NAME("ATSC A/52A (AC-3)"),
115  .p.type = AVMEDIA_TYPE_AUDIO,
116  .p.id = AV_CODEC_ID_AC3,
118  .priv_data_size = sizeof(AC3EncodeContext),
121  .close = ff_ac3_encode_close,
122  .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32P,
124  .p.priv_class = &ff_ac3enc_class,
125  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
126  .p.supported_samplerates = ff_ac3_sample_rate_tab,
127  .p.ch_layouts = ff_ac3_ch_layouts,
128  .defaults = ff_ac3_enc_defaults,
129 };
AV_CODEC_ID_AC3
@ AV_CODEC_ID_AC3
Definition: codec_id.h:443
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: codec_internal.h:42
AVERROR
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
ac3_fixed_mdct_init
static av_cold int ac3_fixed_mdct_init(AVCodecContext *avctx, AC3EncodeContext *s)
Initialize MDCT tables.
Definition: ac3enc_fixed.c:76
COEF_MAX
#define COEF_MAX
Definition: ac3enc.h:63
AV_SAMPLE_FMT_S32P
@ AV_SAMPLE_FMT_S32P
signed 32 bits, planar
Definition: samplefmt.h:65
FFCodec
Definition: codec_internal.h:126
ff_ac3_encode_frame
int ff_ac3_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
Definition: ac3enc.c:1985
av_tx_init
av_cold int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type, int inv, int len, const void *scale, uint64_t flags)
Initialize a transform context with the given configuration (i)MDCTs with an odd length are currently...
Definition: tx.c:903
encode_frame
static int encode_frame(OutputFile *of, OutputStream *ost, AVFrame *frame, AVPacket *pkt)
Definition: ffmpeg_enc.c:607
AudioDSPContext::vector_clip_int32
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
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:130
AVCodecContext::flags
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:502
avpriv_alloc_fixed_dsp
AVFixedDSPContext * avpriv_alloc_fixed_dsp(int bit_exact)
Allocate and initialize a fixed DSP context.
Definition: fixed_dsp.c:151
FF_CODEC_ENCODE_CB
#define FF_CODEC_ENCODE_CB(func)
Definition: codec_internal.h:295
ff_sqrt
#define ff_sqrt
Definition: mathops.h:216
ac3_fixed_encode_init
static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
Definition: ac3enc_fixed.c:96
ff_ac3_ch_layouts
const AVChannelLayout ff_ac3_ch_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:156
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:198
AV_TX_INT32_MDCT
@ AV_TX_INT32_MDCT
Definition: tx.h:70
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE
#define AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE
This encoder can reorder user opaque values from input AVFrames and return them with corresponding ou...
Definition: codec.h:159
kbdwin.h
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:271
ff_ac3_fixed_encoder
const FFCodec ff_ac3_fixed_encoder
Definition: ac3enc_fixed.c:112
ac3enc.h
CoefSumType
int64_t CoefSumType
Definition: ac3enc.h:67
COEF_MIN
#define COEF_MIN
Definition: ac3enc.h:62
AC3EncodeContext
AC-3 encoder private context.
Definition: ac3enc.h:158
ac3enc_template.c
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:366
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
clip_coefficients
static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef, unsigned int len)
Definition: ac3enc_fixed.c:46
codec_internal.h
AC3_BLOCK_SIZE
#define AC3_BLOCK_SIZE
Definition: ac3defs.h:30
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:56
calc_cpl_coord
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
Definition: ac3enc_fixed.c:56
eac3enc.h
ff_ac3_sample_rate_tab
const int ff_ac3_sample_rate_tab[]
Definition: ac3tab.c:95
lrintf
#define lrintf(x)
Definition: libm_mips.h:72
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:55
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:194
len
int len
Definition: vorbis_enc_data.h:426
sum_square_butterfly
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:36
ret
ret
Definition: filter_design.txt:187
AVCodecContext
main external API structure.
Definition: avcodec.h:445
ff_kbd_window_init
av_cold void ff_kbd_window_init(float *window, float alpha, int n)
Generate a Kaiser-Bessel Derived Window.
Definition: kbdwin.c:54
CoefType
int32_t CoefType
Definition: ac3enc.h:66
ff_ac3enc_class
const AVClass ff_ac3enc_class
Definition: ac3enc.c:134
ff_ac3_enc_defaults
const FFCodecDefault ff_ac3_enc_defaults[]
Definition: ac3enc.c:141
ff_ac3_encode_init
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
Definition: ac3enc.c:2476
audiodsp.h
AV_CODEC_FLAG_BITEXACT
#define AV_CODEC_FLAG_BITEXACT
Use only bitexact stuff (except (I)DCT).
Definition: avcodec.h:342
AudioDSPContext
Definition: audiodsp.h:24
scale
static void scale(int *out, const int *in, const int w, const int h, const int shift)
Definition: intra.c:291
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:472
ff_ac3_encode_close
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
Finalize encoding and free any memory allocated by the encoder.
Definition: ac3enc.c:2158
int32_t
int32_t
Definition: audioconvert.c:56