FFmpeg  2.1.1
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 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 = {
40  .class_name = "AC-3 Encoder",
41  .item_name = av_default_item_name,
42  .option = ac3_options,
43  .version = LIBAVUTIL_VERSION_INT,
44 };
45 #endif
46 
47 #include "ac3enc_template.c"
48 
49 
50 /**
51  * Finalize MDCT and free allocated memory.
52  *
53  * @param s AC-3 encoder private context
54  */
56 {
57  ff_mdct_end(&s->mdct);
58  av_freep(&s->mdct_window);
59 }
60 
61 
62 /**
63  * Initialize MDCT tables.
64  *
65  * @param s AC-3 encoder private context
66  * @return 0 on success, negative error code on failure
67  */
69 {
70  float *window;
71  int i, n, n2;
72 
73  n = 1 << 9;
74  n2 = n >> 1;
75 
76  window = av_malloc(n * sizeof(*window));
77  if (!window) {
78  av_log(s->avctx, AV_LOG_ERROR, "Cannot allocate memory.\n");
79  return AVERROR(ENOMEM);
80  }
81  ff_kbd_window_init(window, 5.0, n2);
82  for (i = 0; i < n2; i++)
83  window[n-1-i] = window[i];
84  s->mdct_window = window;
85 
86  return ff_mdct_init(&s->mdct, 9, 0, -2.0 / n);
87 }
88 
89 
90 /*
91  * Apply KBD window to input samples prior to MDCT.
92  */
93 static void apply_window(void *dsp, float *output,
94  const float *input, const float *window,
95  unsigned int len)
96 {
98  fdsp->vector_fmul(output, input, window, len);
99 }
100 
101 
102 /*
103  * Normalize the input samples.
104  * Not needed for the floating-point encoder.
105  */
107 {
108  return 0;
109 }
110 
111 
112 /*
113  * Scale MDCT coefficients from float to 24-bit fixed-point.
114  */
116 {
117  int chan_size = AC3_MAX_COEFS * s->num_blocks;
118  int cpl = s->cpl_on;
119  s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl),
120  s->mdct_coef_buffer + (chan_size * !cpl),
121  chan_size * (s->channels + cpl));
122 }
123 
124 static void sum_square_butterfly(AC3EncodeContext *s, float sum[4],
125  const float *coef0, const float *coef1,
126  int len)
127 {
128  s->ac3dsp.sum_square_butterfly_float(sum, coef0, coef1, len);
129 }
130 
131 /*
132  * Clip MDCT coefficients to allowable range.
133  */
134 static void clip_coefficients(DSPContext *dsp, float *coef, unsigned int len)
135 {
136  dsp->vector_clipf(coef, coef, COEF_MIN, COEF_MAX, len);
137 }
138 
139 
140 /*
141  * Calculate a single coupling coordinate.
142  */
143 static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
144 {
145  float coord = 0.125;
146  if (energy_cpl > 0)
147  coord *= sqrtf(energy_ch / energy_cpl);
148  return FFMIN(coord, COEF_MAX);
149 }
150 
151 
152 #if CONFIG_AC3_ENCODER
153 AVCodec ff_ac3_encoder = {
154  .name = "ac3",
155  .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
156  .type = AVMEDIA_TYPE_AUDIO,
157  .id = AV_CODEC_ID_AC3,
158  .priv_data_size = sizeof(AC3EncodeContext),
160  .encode2 = ff_ac3_float_encode_frame,
162  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
164  .priv_class = &ac3enc_class,
165  .channel_layouts = ff_ac3_channel_layouts,
166  .defaults = ac3_defaults,
167 };
168 #endif
const char * s
Definition: avisynth_c.h:668
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&lt;&lt;24),(1&lt;&lt;24)].
Definition: ac3dsp.h:89
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: avcodec.h:820
#define AC3_MAX_COEFS
Definition: ac3.h:34
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
void(* sum_square_butterfly_float)(float sum[4], const float *coef0, const float *coef1, int len)
Definition: ac3dsp.h:132
#define COEF_MIN
Definition: ac3enc.h:64
void av_log(void *avcl, int level, const char *fmt,...) av_printf_format(3
Send the specified message to the log if the level is less than or equal to the current av_log_level...
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
Definition: ac3enc_float.c:143
AVCodec.
Definition: avcodec.h:2922
#define av_cold
Definition: avcodec.h:653
DSPContext dsp
Definition: ac3enc.h:162
void av_freep(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:234
int ff_ac3_float_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
static void sum_square_butterfly(AC3EncodeContext *s, float sum[4], const float *coef0, const float *coef1, int len)
Definition: ac3enc_float.c:124
const char * av_default_item_name(void *ctx)
Return the context name.
Definition: log.c:145
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:55
const char * name
Name of the codec implementation.
Definition: avcodec.h:2929
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
Finalize encoding and free any memory allocated by the encoder.
Definition: ac3enc.c:2014
AC3DSPContext ac3dsp
AC-3 optimized functions.
Definition: ac3enc.h:164
int64_t CoefSumType
Definition: ac3enc.h:69
static int normalize_samples(AC3EncodeContext *s)
Definition: ac3enc_float.c:106
const uint64_t ff_ac3_channel_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:78
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: avcodec.h:4147
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:38
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:151
int cpl_on
coupling turned on for this frame
Definition: ac3enc.h:208
#define ff_mdct_init
Definition: fft.h:160
static void scale_coefficients(AC3EncodeContext *s)
Definition: ac3enc_float.c:115
int ff_ac3_float_mdct_init(AC3EncodeContext *s)
Initialize MDCT tables.
Definition: ac3enc_float.c:68
void * av_malloc(size_t size) av_malloc_attrib 1(1)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:73
#define FFMIN(a, b)
Definition: avcodec.h:925
int n
Definition: avisynth_c.h:588
FFTContext mdct
FFT context for MDCT calculation.
Definition: ac3enc.h:165
AVFloatDSPContext fdsp
Definition: ac3enc.h:163
const SampleType * mdct_window
MDCT window function array.
Definition: ac3enc.h:166
AVSampleFormat
Audio Sample Formats.
Definition: samplefmt.h:49
void(* vector_clipf)(float *dst, const float *src, float min, float max, int len)
Definition: dsputil.h:212
CoefType * mdct_coef_buffer
Definition: ac3enc.h:234
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:538
Describe the class of an AVClass context structure.
Definition: log.h:50
static void clip_coefficients(DSPContext *dsp, float *coef, unsigned int len)
Definition: ac3enc_float.c:134
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:161
static const AVClass ac3enc_class
Definition: ac3enc_fixed.c:38
static void apply_window(void *dsp, float *output, const float *input, const float *window, unsigned int len)
Definition: ac3enc_float.c:93
static const AVOption ac3_options[]
AVCodecContext * avctx
parent AVCodecContext
Definition: ac3enc.h:160
int len
#define AVERROR(e)
float, planar
Definition: samplefmt.h:60
void ff_ac3_float_mdct_end(AC3EncodeContext *s)
Finalize MDCT and free allocated memory.
Definition: ac3enc_float.c:55
AC-3 encoder &amp; E-AC-3 encoder common header.
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:700
int32_t CoefType
Definition: ac3enc.h:68
E-AC-3 encoder.
int32_t * fixed_coef_buffer
Definition: ac3enc.h:235
DSPContext.
Definition: dsputil.h:124
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
Definition: ac3enc.c:2419