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 Libav.
8  *
9  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
29 #define CONFIG_AC3ENC_FLOAT 1
30 #include "internal.h"
31 #include "ac3enc.h"
32 #include "eac3enc.h"
33 #include "kbdwin.h"
34 
35 
36 #if CONFIG_AC3_ENCODER
37 #define AC3ENC_TYPE AC3ENC_TYPE_AC3
38 #include "ac3enc_opts_template.c"
39 static const AVClass ac3enc_class = { "AC-3 Encoder", av_default_item_name,
41 #endif
42 
43 #include "ac3enc_template.c"
44 
45 
52 {
53  ff_mdct_end(&s->mdct);
54  av_freep(&s->mdct_window);
55 }
56 
57 
65 {
66  float *window;
67  int i, n, n2;
68 
69  n = 1 << 9;
70  n2 = n >> 1;
71 
72  window = av_malloc(n * sizeof(*window));
73  if (!window) {
74  av_log(s->avctx, AV_LOG_ERROR, "Cannot allocate memory.\n");
75  return AVERROR(ENOMEM);
76  }
77  ff_kbd_window_init(window, 5.0, n2);
78  for (i = 0; i < n2; i++)
79  window[n-1-i] = window[i];
80  s->mdct_window = window;
81 
82  return ff_mdct_init(&s->mdct, 9, 0, -2.0 / n);
83 }
84 
85 
86 /*
87  * Apply KBD window to input samples prior to MDCT.
88  */
89 static void apply_window(void *dsp, float *output,
90  const float *input, const float *window,
91  unsigned int len)
92 {
94  fdsp->vector_fmul(output, input, window, len);
95 }
96 
97 
98 /*
99  * Normalize the input samples.
100  * Not needed for the floating-point encoder.
101  */
103 {
104  return 0;
105 }
106 
107 
108 /*
109  * Scale MDCT coefficients from float to 24-bit fixed-point.
110  */
112 {
113  int chan_size = AC3_MAX_COEFS * s->num_blocks;
114  int cpl = s->cpl_on;
115  s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl),
116  s->mdct_coef_buffer + (chan_size * !cpl),
117  chan_size * (s->channels + cpl));
118 }
119 
120 
121 /*
122  * Clip MDCT coefficients to allowable range.
123  */
124 static void clip_coefficients(DSPContext *dsp, float *coef, unsigned int len)
125 {
126  dsp->vector_clipf(coef, coef, COEF_MIN, COEF_MAX, len);
127 }
128 
129 
130 /*
131  * Calculate a single coupling coordinate.
132  */
133 static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
134 {
135  float coord = 0.125;
136  if (energy_cpl > 0)
137  coord *= sqrtf(energy_ch / energy_cpl);
138  return FFMIN(coord, COEF_MAX);
139 }
140 
141 
142 #if CONFIG_AC3_ENCODER
143 AVCodec ff_ac3_encoder = {
144  .name = "ac3",
145  .type = AVMEDIA_TYPE_AUDIO,
146  .id = AV_CODEC_ID_AC3,
147  .priv_data_size = sizeof(AC3EncodeContext),
149  .encode2 = ff_ac3_float_encode_frame,
151  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
153  .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
154  .priv_class = &ac3enc_class,
155  .channel_layouts = ff_ac3_channel_layouts,
156  .defaults = ac3_defaults,
157 };
158 #endif
void * av_malloc(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:61
void(* float_to_fixed24)(int32_t *dst, const float *src, unsigned int len)
Convert an array of float in range [-1.0,1.0] to int32_t with range [-(1<<24),(1<<24)].
Definition: ac3dsp.h:89
struct AC3EncodeContext AC3EncodeContext
AC-3 encoder private context.
av_cold void ff_kbd_window_init(float *window, float alpha, int n)
Generate a Kaiser-Bessel Derived Window.
Definition: kbdwin.c:26
#define AC3_MAX_COEFS
Definition: ac3.h:34
#define COEF_MIN
Definition: ac3enc.h:64
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
Definition: ac3enc_float.c:133
AVCodec.
Definition: avcodec.h:2960
DSPContext dsp
Definition: ac3enc.h:162
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:151
int ff_ac3_float_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
Finalize encoding and free any memory allocated by the encoder.
Definition: ac3enc.c:2018
av_cold int ff_ac3_float_mdct_init(AC3EncodeContext *s)
Initialize MDCT tables.
Definition: ac3enc_float.c:64
AC3DSPContext ac3dsp
AC-3 optimized functions.
Definition: ac3enc.h:164
static int init(AVCodecParserContext *s)
Definition: h264_parser.c:335
float, planar
Definition: samplefmt.h:60
int64_t CoefSumType
Definition: ac3enc.h:69
static int normalize_samples(AC3EncodeContext *s)
Definition: ac3enc_float.c:102
const uint64_t ff_ac3_channel_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:79
void(* vector_fmul)(float *dst, const float *src0, const float *src1, int len)
Calculate the product of two vectors of floats and store the result in a vector of floats...
Definition: float_dsp.h:36
sample_fmts
Definition: avconv_filter.c:63
int channels
total number of channels (nchans)
Definition: ac3enc.h:188
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:88
int cpl_on
coupling turned on for this frame
Definition: ac3enc.h:208
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:146
const char * name
Name of the codec implementation.
Definition: avcodec.h:2967
#define ff_mdct_init
Definition: fft.h:146
static void scale_coefficients(AC3EncodeContext *s)
Definition: ac3enc_float.c:111
FFTContext mdct
FFT context for MDCT calculation.
Definition: ac3enc.h:165
LIBAVUTIL_VERSION_INT
Definition: eval.c:52
AVFloatDSPContext fdsp
Definition: ac3enc.h:163
const SampleType * mdct_window
MDCT window function array.
Definition: ac3enc.h:166
AV_SAMPLE_FMT_NONE
Definition: avconv_filter.c:63
av_default_item_name
Definition: dnxhdenc.c:43
void(* vector_clipf)(float *dst, const float *src, float min, float max, int len)
Definition: dsputil.h:360
CoefType * mdct_coef_buffer
Definition: ac3enc.h:234
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:326
Describe the class of an AVClass context structure.
Definition: log.h:33
static void clip_coefficients(DSPContext *dsp, float *coef, unsigned int len)
Definition: ac3enc_float.c:124
static const AVCodecDefault ac3_defaults[]
AC-3 encoder private context.
Definition: ac3enc.h:157
int num_blocks
number of blocks per frame
Definition: ac3enc.h:179
#define COEF_MAX
Definition: ac3enc.h:65
AC-3 encoder float/fixed template.
common internal api header.
#define ff_mdct_end
Definition: fft.h:147
static const AVClass ac3enc_class
Definition: ac3enc_fixed.c:37
AVSampleFormat
Audio Sample Formats.
Definition: samplefmt.h:49
static void apply_window(void *dsp, float *output, const float *input, const float *window, unsigned int len)
Definition: ac3enc_float.c:89
static const AVOption ac3_options[]
AVCodecContext * avctx
parent AVCodecContext
Definition: ac3enc.h:160
int len
AC-3 encoder & E-AC-3 encoder common header.
int32_t CoefType
Definition: ac3enc.h:68
E-AC-3 encoder.
av_cold void ff_ac3_float_mdct_end(AC3EncodeContext *s)
Finalize MDCT and free allocated memory.
Definition: ac3enc_float.c:51
int32_t * fixed_coef_buffer
Definition: ac3enc.h:235
DSPContext.
Definition: dsputil.h:194
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
Definition: ac3enc.c:2425