FFmpeg
ac3enc_float.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  * floating-point AC-3 encoder.
27  */
28 
29 #define AC3ENC_FLOAT 1
30 #include "internal.h"
31 #include "audiodsp.h"
32 #include "ac3enc.h"
33 #include "eac3enc.h"
34 #include "kbdwin.h"
35 
36 
37 /*
38  * Scale MDCT coefficients from float to 24-bit fixed-point.
39  */
41 {
42  int chan_size = AC3_MAX_COEFS * s->num_blocks;
43  int cpl = s->cpl_on;
44  s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl),
45  s->mdct_coef_buffer + (chan_size * !cpl),
46  chan_size * (s->channels + cpl));
47 }
48 
49 
50 /*
51  * Clip MDCT coefficients to allowable range.
52  */
53 static void clip_coefficients(AudioDSPContext *adsp, float *coef,
54  unsigned int len)
55 {
56  adsp->vector_clipf(coef, coef, len, COEF_MIN, COEF_MAX);
57 }
58 
59 
60 /*
61  * Calculate a single coupling coordinate.
62  */
63 static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
64 {
65  float coord = 0.125;
66  if (energy_cpl > 0)
67  coord *= sqrtf(energy_ch / energy_cpl);
68  return FFMIN(coord, COEF_MAX);
69 }
70 
71 static void sum_square_butterfly(AC3EncodeContext *s, float sum[4],
72  const float *coef0, const float *coef1,
73  int len)
74 {
75  s->ac3dsp.sum_square_butterfly_float(sum, coef0, coef1, len);
76 }
77 
78 
79 #include "ac3enc_template.c"
80 
81 
82 /**
83  * Finalize MDCT and free allocated memory.
84  *
85  * @param s AC-3 encoder private context
86  */
88 {
89  ff_mdct_end(&s->mdct);
90 }
91 
92 
93 /**
94  * Initialize MDCT tables.
95  *
96  * @param s AC-3 encoder private context
97  * @return 0 on success, negative error code on failure
98  */
100 {
101  float *window = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*window));
102  if (!window) {
103  av_log(s->avctx, AV_LOG_ERROR, "Cannot allocate memory.\n");
104  return AVERROR(ENOMEM);
105  }
106 
108  s->mdct_window = window;
109 
110  return ff_mdct_init(&s->mdct, 9, 0, -2.0 / AC3_WINDOW_SIZE);
111 }
112 
113 
115 {
117  s->mdct_end = ac3_float_mdct_end;
118  s->mdct_init = ac3_float_mdct_init;
119  s->allocate_sample_buffers = allocate_sample_buffers;
121  if (!s->fdsp)
122  return AVERROR(ENOMEM);
123  return ff_ac3_encode_init(avctx);
124 }
125 
127  .name = "ac3",
128  .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
129  .type = AVMEDIA_TYPE_AUDIO,
130  .id = AV_CODEC_ID_AC3,
131  .capabilities = AV_CODEC_CAP_DR1,
132  .priv_data_size = sizeof(AC3EncodeContext),
134  .encode2 = ff_ac3_float_encode_frame,
135  .close = ff_ac3_encode_close,
136  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
138  .priv_class = &ff_ac3enc_class,
139  .supported_samplerates = ff_ac3_sample_rate_tab,
140  .channel_layouts = ff_ac3_channel_layouts,
141  .defaults = ff_ac3_enc_defaults,
143 };
AVCodec
AVCodec.
Definition: codec.h:197
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:69
FF_CODEC_CAP_INIT_THREADSAFE
#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:42
AudioDSPContext::vector_clipf
void(* vector_clipf)(float *dst, const float *src, int len, float min, float max)
Definition: audiodsp.h:49
AV_CODEC_ID_AC3
@ AV_CODEC_ID_AC3
Definition: codec_id.h:425
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
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
ff_ac3_enc_defaults
const AVCodecDefault ff_ac3_enc_defaults[]
Definition: ac3enc.c:135
COEF_MAX
#define COEF_MAX
Definition: ac3enc.h:62
sample_fmts
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:948
internal.h
AC3_MAX_COEFS
#define AC3_MAX_COEFS
Definition: ac3.h:37
ff_mdct_init
#define ff_mdct_init
Definition: fft.h:161
sum_square_butterfly
static void sum_square_butterfly(AC3EncodeContext *s, float sum[4], const float *coef0, const float *coef1, int len)
Definition: ac3enc_float.c:71
allocate_sample_buffers
static int allocate_sample_buffers(AC3EncodeContext *s)
Definition: ac3enc_template.c:41
ff_ac3_float_encode_frame
int ff_ac3_float_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
window
static SDL_Window * window
Definition: ffplay.c:364
AVCodecContext::flags
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:459
ac3_float_mdct_end
static av_cold void ac3_float_mdct_end(AC3EncodeContext *s)
Finalize MDCT and free allocated memory.
Definition: ac3enc_float.c:87
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:257
ff_ac3_channel_layouts
const uint64_t ff_ac3_channel_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:150
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
kbdwin.h
ac3enc.h
ff_ac3_encoder
const AVCodec ff_ac3_encoder
Definition: ac3enc_float.c:126
CoefSumType
int64_t CoefSumType
Definition: ac3enc.h:66
COEF_MIN
#define COEF_MIN
Definition: ac3enc.h:61
AC3EncodeContext
AC-3 encoder private context.
Definition: ac3enc.h:155
ff_ac3_float_encode_init
av_cold int ff_ac3_float_encode_init(AVCodecContext *avctx)
Definition: ac3enc_float.c:114
scale_coefficients
static void scale_coefficients(AC3EncodeContext *s)
Definition: ac3enc_float.c:40
AC3EncodeContext::adsp
AudioDSPContext adsp
Definition: ac3enc.h:160
ac3enc_template.c
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
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:116
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
ff_mdct_end
#define ff_mdct_end
Definition: fft.h:162
FFMIN
#define FFMIN(a, b)
Definition: common.h:105
eac3enc.h
ff_ac3_sample_rate_tab
const int ff_ac3_sample_rate_tab[]
Definition: ac3tab.c:110
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: internal.h:50
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:32
ac3_float_mdct_init
static av_cold int ac3_float_mdct_init(AC3EncodeContext *s)
Initialize MDCT tables.
Definition: ac3enc_float.c:99
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
len
int len
Definition: vorbis_enc_data.h:426
clip_coefficients
static void clip_coefficients(AudioDSPContext *adsp, float *coef, unsigned int len)
Definition: ac3enc_float.c:53
AVCodecContext
main external API structure.
Definition: avcodec.h:379
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:26
CoefType
int32_t CoefType
Definition: ac3enc.h:65
ff_ac3enc_class
const AVClass ff_ac3enc_class
Definition: ac3enc.c:128
ff_ac3_encode_init
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
Definition: ac3enc.c:2516
audiodsp.h
AV_CODEC_FLAG_BITEXACT
#define AV_CODEC_FLAG_BITEXACT
Use only bitexact stuff (except (I)DCT).
Definition: avcodec.h:268
AudioDSPContext
Definition: audiodsp.h:24
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:406
AC3EncodeContext::avctx
AVCodecContext * avctx
parent AVCodecContext
Definition: ac3enc.h:158
avpriv_float_dsp_alloc
av_cold AVFloatDSPContext * avpriv_float_dsp_alloc(int bit_exact)
Allocate a float DSP context.
Definition: float_dsp.c:135
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:2123
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AC3_WINDOW_SIZE
#define AC3_WINDOW_SIZE
Definition: ac3.h:41
calc_cpl_coord
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
Definition: ac3enc_float.c:63
AC3_BLOCK_SIZE
#define AC3_BLOCK_SIZE
Definition: ac3.h:38