FFmpeg
aaccoder_trellis.h
Go to the documentation of this file.
1 /*
2  * AAC encoder trellis codebook selector
3  * Copyright (C) 2008-2009 Konstantin Shishkov
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * AAC encoder trellis codebook selector
25  * @author Konstantin Shishkov
26  */
27 
28 /**
29  * This file contains a template for the codebook_trellis_rate selector function.
30  * It needs to be provided, externally, as an already included declaration,
31  * the following functions from aacenc_quantization/util.h. They're not included
32  * explicitly here to make it possible to provide alternative implementations:
33  * - quantize_band_cost_bits
34  * - abs_pow34_v
35  */
36 
37 #ifndef AVCODEC_AACCODER_TRELLIS_H
38 #define AVCODEC_AACCODER_TRELLIS_H
39 
40 #include <float.h>
41 #include "libavutil/mathematics.h"
42 #include "avcodec.h"
43 #include "put_bits.h"
44 #include "aac.h"
45 #include "aacenc.h"
46 #include "aactab.h"
47 #include "aacenctab.h"
48 
49 /**
50  * structure used in optimal codebook search
51  */
52 typedef struct TrellisBandCodingPath {
53  int prev_idx; ///< pointer to the previous path point
54  float cost; ///< path cost
55  int run;
56 } TrellisBandCodingPath;
57 
58 
59 static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
60  int win, int group_len, const float lambda)
61 {
62  TrellisBandCodingPath path[120][CB_TOT_ALL];
63  int w, swb, cb, start, size;
64  int i, j;
65  const int max_sfb = sce->ics.max_sfb;
66  const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
67  const int run_esc = (1 << run_bits) - 1;
68  int idx, ppos, count;
69  int stackrun[120], stackcb[120], stack_len;
70  float next_minbits = INFINITY;
71  int next_mincb = 0;
72 
73  s->abs_pow34(s->scoefs, sce->coeffs, 1024);
74  start = win*128;
75  for (cb = 0; cb < CB_TOT_ALL; cb++) {
76  path[0][cb].cost = run_bits+4;
77  path[0][cb].prev_idx = -1;
78  path[0][cb].run = 0;
79  }
80  for (swb = 0; swb < max_sfb; swb++) {
81  size = sce->ics.swb_sizes[swb];
82  if (sce->zeroes[win*16 + swb]) {
83  float cost_stay_here = path[swb][0].cost;
84  float cost_get_here = next_minbits + run_bits + 4;
85  if ( run_value_bits[sce->ics.num_windows == 8][path[swb][0].run]
86  != run_value_bits[sce->ics.num_windows == 8][path[swb][0].run+1])
87  cost_stay_here += run_bits;
88  if (cost_get_here < cost_stay_here) {
89  path[swb+1][0].prev_idx = next_mincb;
90  path[swb+1][0].cost = cost_get_here;
91  path[swb+1][0].run = 1;
92  } else {
93  path[swb+1][0].prev_idx = 0;
94  path[swb+1][0].cost = cost_stay_here;
95  path[swb+1][0].run = path[swb][0].run + 1;
96  }
97  next_minbits = path[swb+1][0].cost;
98  next_mincb = 0;
99  for (cb = 1; cb < CB_TOT_ALL; cb++) {
100  path[swb+1][cb].cost = 61450;
101  path[swb+1][cb].prev_idx = -1;
102  path[swb+1][cb].run = 0;
103  }
104  } else {
105  float minbits = next_minbits;
106  int mincb = next_mincb;
107  int startcb = sce->band_type[win*16+swb];
108  startcb = aac_cb_in_map[startcb];
109  next_minbits = INFINITY;
110  next_mincb = 0;
111  for (cb = 0; cb < startcb; cb++) {
112  path[swb+1][cb].cost = 61450;
113  path[swb+1][cb].prev_idx = -1;
114  path[swb+1][cb].run = 0;
115  }
116  for (cb = startcb; cb < CB_TOT_ALL; cb++) {
117  float cost_stay_here, cost_get_here;
118  float bits = 0.0f;
119  if (cb >= 12 && sce->band_type[win*16+swb] != aac_cb_out_map[cb]) {
120  path[swb+1][cb].cost = 61450;
121  path[swb+1][cb].prev_idx = -1;
122  path[swb+1][cb].run = 0;
123  continue;
124  }
125  for (w = 0; w < group_len; w++) {
126  bits += quantize_band_cost_bits(s, &sce->coeffs[start + w*128],
127  &s->scoefs[start + w*128], size,
128  sce->sf_idx[win*16+swb],
129  aac_cb_out_map[cb],
130  0, INFINITY, NULL, NULL, 0);
131  }
132  cost_stay_here = path[swb][cb].cost + bits;
133  cost_get_here = minbits + bits + run_bits + 4;
134  if ( run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
135  != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
136  cost_stay_here += run_bits;
137  if (cost_get_here < cost_stay_here) {
138  path[swb+1][cb].prev_idx = mincb;
139  path[swb+1][cb].cost = cost_get_here;
140  path[swb+1][cb].run = 1;
141  } else {
142  path[swb+1][cb].prev_idx = cb;
143  path[swb+1][cb].cost = cost_stay_here;
144  path[swb+1][cb].run = path[swb][cb].run + 1;
145  }
146  if (path[swb+1][cb].cost < next_minbits) {
147  next_minbits = path[swb+1][cb].cost;
148  next_mincb = cb;
149  }
150  }
151  }
152  start += sce->ics.swb_sizes[swb];
153  }
154 
155  //convert resulting path from backward-linked list
156  stack_len = 0;
157  idx = 0;
158  for (cb = 1; cb < CB_TOT_ALL; cb++)
159  if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
160  idx = cb;
161  ppos = max_sfb;
162  while (ppos > 0) {
163  av_assert1(idx >= 0);
164  cb = idx;
165  stackrun[stack_len] = path[ppos][cb].run;
166  stackcb [stack_len] = cb;
167  idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
168  ppos -= path[ppos][cb].run;
169  stack_len++;
170  }
171  //perform actual band info encoding
172  start = 0;
173  for (i = stack_len - 1; i >= 0; i--) {
174  cb = aac_cb_out_map[stackcb[i]];
175  put_bits(&s->pb, 4, cb);
176  count = stackrun[i];
177  memset(sce->zeroes + win*16 + start, !cb, count);
178  //XXX: memset when band_type is also uint8_t
179  for (j = 0; j < count; j++) {
180  sce->band_type[win*16 + start] = cb;
181  start++;
182  }
183  while (count >= run_esc) {
184  put_bits(&s->pb, run_bits, run_esc);
185  count -= run_esc;
186  }
187  put_bits(&s->pb, run_bits, count);
188  }
189 }
190 
191 
192 #endif /* AVCODEC_AACCODER_TRELLIS_H */
INFINITY
#define INFINITY
Definition: mathematics.h:67
cb
static double cb(void *priv, double x, double y)
Definition: vf_geq.c:112
aacenctab.h
CB_TOT_ALL
#define CB_TOT_ALL
Total number of codebooks, including special ones.
Definition: aacenctab.h:37
SingleChannelElement::zeroes
uint8_t zeroes[128]
band is not coded (used by encoder)
Definition: aac.h:257
count
void INT64 INT64 count
Definition: avisynth_c.h:767
put_bits
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:208
w
uint8_t w
Definition: llviddspenc.c:38
float.h
mathematics.h
TrellisBandCodingPath::run
int run
Definition: aaccoder_trellis.h:55
win
static float win(SuperEqualizerContext *s, float n, int N)
Definition: af_superequalizer.c:119
TrellisBandCodingPath::cost
float cost
path cost
Definition: aaccoder_trellis.h:54
start
void INT64 start
Definition: avisynth_c.h:767
quantize_band_cost_bits
static int quantize_band_cost_bits(struct AACEncContext *s, const float *in, const float *scaled, int size, int scale_idx, int cb, const float lambda, const float uplim, int *bits, float *energy, int rtz)
Definition: aacenc_quantization.h:259
SingleChannelElement::ics
IndividualChannelStream ics
Definition: aac.h:249
s
#define s(width, name)
Definition: cbs_vp9.c:257
SingleChannelElement::coeffs
INTFLOAT coeffs[1024]
coefficients for IMDCT, maybe processed
Definition: aac.h:262
IndividualChannelStream::swb_sizes
const uint8_t * swb_sizes
table of scalefactor band sizes for a particular window
Definition: aac.h:182
bits
uint8_t bits
Definition: vp3data.h:202
NULL
#define NULL
Definition: coverity.c:32
codebook_trellis_rate
static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce, int win, int group_len, const float lambda)
Definition: aaccoder_trellis.h:59
aac.h
aactab.h
run_value_bits
static const uint8_t *const run_value_bits[2]
Definition: aacenctab.h:116
SingleChannelElement::sf_idx
int sf_idx[128]
scalefactor indices (used by encoder)
Definition: aac.h:256
aac_cb_out_map
static const uint8_t aac_cb_out_map[CB_TOT_ALL]
Map to convert values from BandCodingPath index to a codebook index.
Definition: aacenctab.h:121
TrellisBandCodingPath
This file contains a template for the codebook_trellis_rate selector function.
Definition: aaccoder_trellis.h:52
size
int size
Definition: twinvq_data.h:11134
run_bits
static const uint8_t run_bits[7][16]
Definition: h264_cavlc.c:229
SingleChannelElement
Single Channel Element - used for both SCE and LFE elements.
Definition: aac.h:248
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
IndividualChannelStream::num_windows
int num_windows
Definition: aac.h:184
aac_cb_in_map
static const uint8_t aac_cb_in_map[CB_TOT_ALL+1]
Inverse map to convert from codebooks to BandCodingPath indices.
Definition: aacenctab.h:123
av_assert1
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:53
avcodec.h
AACEncContext
AAC encoder context.
Definition: aacenc.h:376
TrellisBandCodingPath::prev_idx
int prev_idx
pointer to the previous path point
Definition: aaccoder_trellis.h:53
IndividualChannelStream::max_sfb
uint8_t max_sfb
number of scalefactor bands per group
Definition: aac.h:175
put_bits.h
SingleChannelElement::band_type
enum BandType band_type[128]
band types
Definition: aac.h:252
aacenc.h
Generated on Wed Aug 24 2022 21:26:30 for FFmpeg by   doxygen 1.8.17