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 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_FFT_FLOAT 0
30 #undef CONFIG_AC3ENC_FLOAT
31 #include "internal.h"
32 #include "ac3enc.h"
33 #include "eac3enc.h"
34 
35 #define AC3ENC_TYPE AC3ENC_TYPE_AC3_FIXED
36 #include "ac3enc_opts_template.c"
37 static const AVClass ac3enc_class = { "Fixed-Point AC-3 Encoder", av_default_item_name,
39 
40 #include "ac3enc_template.c"
41 
42 
49 {
50  ff_mdct_end(&s->mdct);
51 }
52 
53 
61 {
62  int ret = ff_mdct_init(&s->mdct, 9, 0, -1.0);
63  s->mdct_window = ff_ac3_window;
64  return ret;
65 }
66 
67 
68 /*
69  * Apply KBD window to input samples prior to MDCT.
70  */
71 static void apply_window(void *dsp, int16_t *output, const int16_t *input,
72  const int16_t *window, unsigned int len)
73 {
74  DSPContext *dsp0 = dsp;
75  dsp0->apply_window_int16(output, input, window, len);
76 }
77 
78 
79 /*
80  * Normalize the input samples to use the maximum available precision.
81  * This assumes signed 16-bit input samples.
82  */
84 {
86  v = 14 - av_log2(v);
87  if (v > 0)
89  /* +6 to right-shift from 31-bit to 25-bit */
90  return v + 6;
91 }
92 
93 
94 /*
95  * Scale MDCT coefficients to 25-bit signed fixed-point.
96  */
98 {
99  int blk, ch;
100 
101  for (blk = 0; blk < s->num_blocks; blk++) {
102  AC3Block *block = &s->blocks[blk];
103  for (ch = 1; ch <= s->channels; ch++) {
105  block->coeff_shift[ch]);
106  }
107  }
108 }
109 
110 
111 /*
112  * Clip MDCT coefficients to allowable range.
113  */
114 static void clip_coefficients(DSPContext *dsp, int32_t *coef, unsigned int len)
115 {
116  dsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len);
117 }
118 
119 
120 /*
121  * Calculate a single coupling coordinate.
122  */
123 static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
124 {
125  if (energy_cpl <= COEF_MAX) {
126  return 1048576;
127  } else {
128  uint64_t coord = energy_ch / (energy_cpl >> 24);
129  uint32_t coord32 = FFMIN(coord, 1073741824);
130  coord32 = ff_sqrt(coord32) << 9;
131  return FFMIN(coord32, COEF_MAX);
132  }
133 }
134 
135 
137 {
138  AC3EncodeContext *s = avctx->priv_data;
139  s->fixed_point = 1;
140  return ff_ac3_encode_init(avctx);
141 }
142 
143 
145  .name = "ac3_fixed",
146  .type = AVMEDIA_TYPE_AUDIO,
147  .id = AV_CODEC_ID_AC3,
148  .priv_data_size = sizeof(AC3EncodeContext),
150  .encode2 = ff_ac3_fixed_encode_frame,
152  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16P,
154  .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
155  .priv_class = &ac3enc_class,
156  .channel_layouts = ff_ac3_channel_layouts,
157  .defaults = ac3_defaults,
158 };
void(* ac3_rshift_int32)(int32_t *src, unsigned int len, unsigned int shift)
Right-shift each value in an array of int32_t by a specified amount.
Definition: ac3dsp.h:76
struct AC3EncodeContext AC3EncodeContext
AC-3 encoder private context.
#define AC3_MAX_COEFS
Definition: ac3.h:34
static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
Definition: ac3enc_fixed.c:136
#define AC3_WINDOW_SIZE
Definition: ac3.h:38
#define COEF_MIN
Definition: ac3enc.h:64
void(* apply_window_int16)(int16_t *output, const int16_t *input, const int16_t *window, unsigned int len)
Apply symmetric window in 16-bit fixed-point.
Definition: dsputil.h:470
#define blk(i)
Definition: sha.c:171
AVCodec.
Definition: avcodec.h:2960
DSPContext dsp
Definition: ac3enc.h:162
av_cold int AC3_NAME() mdct_init(AC3EncodeContext *s)
Initialize MDCT tables.
Definition: ac3enc_fixed.c:60
int(* ac3_max_msb_abs_int16)(const int16_t *src, int len)
Calculate the maximum MSB of the absolute value of each element in an array of int16_t.
Definition: ac3dsp.h:54
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
Finalize encoding and free any memory allocated by the encoder.
Definition: ac3enc.c:2018
const int16_t ff_ac3_window[AC3_WINDOW_SIZE/2]
Definition: ac3tab.c:151
AC3DSPContext ac3dsp
AC-3 optimized functions.
Definition: ac3enc.h:164
av_cold void AC3_NAME() mdct_end(AC3EncodeContext *s)
Finalize MDCT and free allocated memory.
Definition: ac3enc_fixed.c:48
static int init(AVCodecParserContext *s)
Definition: h264_parser.c:335
int64_t CoefSumType
Definition: ac3enc.h:69
CoefType ** mdct_coef
MDCT coefficients.
Definition: ac3enc.h:129
const uint64_t ff_ac3_channel_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:79
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
#define AC3_NAME(x)
Definition: ac3enc.h:62
const char * name
Name of the codec implementation.
Definition: avcodec.h:2967
int fixed_point
indicates if fixed-point encoder is being used
Definition: ac3enc.h:170
#define ff_mdct_init
Definition: fft.h:146
Data for a single audio block.
Definition: ac3enc.h:128
static DCTELEM block[64]
Definition: dct-test.c:169
int32_t
LIBAVUTIL_VERSION_INT
Definition: eval.c:52
static void scale_coefficients(AC3EncodeContext *s)
Definition: ac3enc_fixed.c:97
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
Definition: ac3enc_fixed.c:123
static av_const unsigned int ff_sqrt(unsigned int a)
Definition: mathops.h:198
AV_SAMPLE_FMT_NONE
Definition: avconv_filter.c:63
av_default_item_name
Definition: dnxhdenc.c:43
main external API structure.
Definition: avcodec.h:1339
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:326
Describe the class of an AVClass context structure.
Definition: log.h:33
int ff_ac3_fixed_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
static const AVCodecDefault ac3_defaults[]
AC-3 encoder private context.
Definition: ac3enc.h:157
AC3Block blocks[AC3_MAX_BLOCKS]
per-block info
Definition: ac3enc.h:168
SampleType * windowed_samples
Definition: ac3enc.h:230
static void apply_window(void *dsp, int16_t *output, const int16_t *input, const int16_t *window, unsigned int len)
Definition: ac3enc_fixed.c:71
int num_blocks
number of blocks per frame
Definition: ac3enc.h:179
uint8_t coeff_shift[AC3_MAX_CHANNELS]
fixed-point coefficient shift values
Definition: ac3enc.h:139
static void clip_coefficients(DSPContext *dsp, int32_t *coef, unsigned int len)
Definition: ac3enc_fixed.c:114
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: dsputil.h:486
#define COEF_MAX
Definition: ac3enc.h:65
AC-3 encoder float/fixed template.
common internal api header.
AVCodec ff_ac3_fixed_encoder
Definition: ac3enc_fixed.c:144
#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
void(* ac3_lshift_int16)(int16_t *src, unsigned int len, unsigned int shift)
Left-shift each value in an array of int16_t by a specified amount.
Definition: ac3dsp.h:65
static const AVOption ac3_options[]
AVCodecContext * avctx
parent AVCodecContext
Definition: ac3enc.h:160
void * priv_data
Definition: avcodec.h:1382
int len
#define av_log2
Definition: intmath.h:85
signed 16 bits, planar
Definition: samplefmt.h:58
static int normalize_samples(AC3EncodeContext *s)
Definition: ac3enc_fixed.c:83
AC-3 encoder & E-AC-3 encoder common header.
int32_t CoefType
Definition: ac3enc.h:68
E-AC-3 encoder.
DSPContext.
Definition: dsputil.h:194
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
Definition: ac3enc.c:2425