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mpeg4audio.c
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1 /*
2  * MPEG-4 Audio common code
3  * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
4  * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "get_bits.h"
24 #include "put_bits.h"
25 #include "mpeg4audio.h"
26 
27 /**
28  * Parse MPEG-4 audio configuration for ALS object type.
29  * @param[in] gb bit reader context
30  * @param[in] c MPEG4AudioConfig structure to fill
31  * @return on success 0 is returned, otherwise a value < 0
32  */
34 {
35  if (get_bits_left(gb) < 112)
36  return -1;
37 
38  if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
39  return -1;
40 
41  // override AudioSpecificConfig channel configuration and sample rate
42  // which are buggy in old ALS conformance files
43  c->sample_rate = get_bits_long(gb, 32);
44 
45  // skip number of samples
46  skip_bits_long(gb, 32);
47 
48  // read number of channels
49  c->chan_config = 0;
50  c->channels = get_bits(gb, 16) + 1;
51 
52  return 0;
53 }
54 
55 /* XXX: make sure to update the copies in the different encoders if you change
56  * this table */
58  96000, 88200, 64000, 48000, 44100, 32000,
59  24000, 22050, 16000, 12000, 11025, 8000, 7350
60 };
61 
63  0, 1, 2, 3, 4, 5, 6, 8
64 };
65 
66 static inline int get_object_type(GetBitContext *gb)
67 {
68  int object_type = get_bits(gb, 5);
69  if (object_type == AOT_ESCAPE)
70  object_type = 32 + get_bits(gb, 6);
71  return object_type;
72 }
73 
74 static inline int get_sample_rate(GetBitContext *gb, int *index)
75 {
76  *index = get_bits(gb, 4);
77  return *index == 0x0f ? get_bits(gb, 24) :
79 }
80 
82  int bit_size, int sync_extension)
83 {
84  GetBitContext gb;
85  int specific_config_bitindex, ret;
86 
87  if (bit_size <= 0)
88  return AVERROR_INVALIDDATA;
89 
90  ret = init_get_bits(&gb, buf, bit_size);
91  if (ret < 0)
92  return ret;
93 
94  c->object_type = get_object_type(&gb);
96  c->chan_config = get_bits(&gb, 4);
99  c->sbr = -1;
100  c->ps = -1;
101  if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
102  // check for W6132 Annex YYYY draft MP3onMP4
103  !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) {
104  if (c->object_type == AOT_PS)
105  c->ps = 1;
107  c->sbr = 1;
109  c->object_type = get_object_type(&gb);
110  if (c->object_type == AOT_ER_BSAC)
111  c->ext_chan_config = get_bits(&gb, 4);
112  } else {
114  c->ext_sample_rate = 0;
115  }
116  specific_config_bitindex = get_bits_count(&gb);
117 
118  if (c->object_type == AOT_ALS) {
119  skip_bits(&gb, 5);
120  if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S'))
121  skip_bits_long(&gb, 24);
122 
123  specific_config_bitindex = get_bits_count(&gb);
124 
125  if (parse_config_ALS(&gb, c))
126  return -1;
127  }
128 
129  if (c->ext_object_type != AOT_SBR && sync_extension) {
130  while (get_bits_left(&gb) > 15) {
131  if (show_bits(&gb, 11) == 0x2b7) { // sync extension
132  get_bits(&gb, 11);
134  if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) {
136  if (c->ext_sample_rate == c->sample_rate)
137  c->sbr = -1;
138  }
139  if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548)
140  c->ps = get_bits1(&gb);
141  break;
142  } else
143  get_bits1(&gb); // skip 1 bit
144  }
145  }
146 
147  //PS requires SBR
148  if (!c->sbr)
149  c->ps = 0;
150  //Limit implicit PS to the HE-AACv2 Profile
151  if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
152  c->ps = 0;
153 
154  return specific_config_bitindex;
155 }
156 
157 static av_always_inline unsigned int copy_bits(PutBitContext *pb,
158  GetBitContext *gb,
159  int bits)
160 {
161  unsigned int el = get_bits(gb, bits);
162  put_bits(pb, bits, el);
163  return el;
164 }
165 
167 {
168  int five_bit_ch, four_bit_ch, comment_size, bits;
169  int offset = put_bits_count(pb);
170 
171  copy_bits(pb, gb, 10); //Tag, Object Type, Frequency
172  five_bit_ch = copy_bits(pb, gb, 4); //Front
173  five_bit_ch += copy_bits(pb, gb, 4); //Side
174  five_bit_ch += copy_bits(pb, gb, 4); //Back
175  four_bit_ch = copy_bits(pb, gb, 2); //LFE
176  four_bit_ch += copy_bits(pb, gb, 3); //Data
177  five_bit_ch += copy_bits(pb, gb, 4); //Coupling
178  if (copy_bits(pb, gb, 1)) //Mono Mixdown
179  copy_bits(pb, gb, 4);
180  if (copy_bits(pb, gb, 1)) //Stereo Mixdown
181  copy_bits(pb, gb, 4);
182  if (copy_bits(pb, gb, 1)) //Matrix Mixdown
183  copy_bits(pb, gb, 3);
184  for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16)
185  copy_bits(pb, gb, 16);
186  if (bits)
187  copy_bits(pb, gb, bits);
189  align_get_bits(gb);
190  comment_size = copy_bits(pb, gb, 8);
191  for (; comment_size > 0; comment_size--)
192  copy_bits(pb, gb, 8);
193 
194  return put_bits_count(pb) - offset;
195 }
static unsigned int show_bits_long(GetBitContext *s, int n)
Show 0-32 bits.
Definition: get_bits.h:383
N Parametric Stereo.
Definition: mpeg4audio.h:86
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:160
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:260
static void skip_bits_long(GetBitContext *s, int n)
Definition: get_bits.h:217
static int get_sample_rate(GetBitContext *gb, int *index)
Definition: mpeg4audio.c:74
void avpriv_align_put_bits(PutBitContext *s)
Pad the bitstream with zeros up to the next byte boundary.
Definition: bitstream.c:48
#define FF_ARRAY_ELEMS(a)
uint8_t bits
Definition: crc.c:295
uint8_t
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:212
bitstream reader API header.
Y Escape Value.
Definition: mpeg4audio.h:88
static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)
Parse MPEG-4 audio configuration for ALS object type.
Definition: mpeg4audio.c:33
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:588
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
static int put_bits_count(PutBitContext *s)
Definition: put_bits.h:85
ret
Definition: avfilter.c:974
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:287
void * buf
Definition: avisynth_c.h:553
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:304
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:297
int index
Definition: gxfenc.c:89
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:410
N Error Resilient Bit-Sliced Arithmetic Coding.
Definition: mpeg4audio.h:79
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:337
static int get_object_type(GetBitContext *gb)
Definition: mpeg4audio.c:66
const int avpriv_mpeg4audio_sample_rates[16]
Definition: mpeg4audio.c:57
Y Spectral Band Replication.
Definition: mpeg4audio.h:65
static double c[64]
int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, int bit_size, int sync_extension)
Parse MPEG-4 systems extradata to retrieve audio configuration.
Definition: mpeg4audio.c:81
#define MKBETAG(a, b, c, d)
Definition: common.h:316
Y Audio LosslesS.
Definition: mpeg4audio.h:93
const uint8_t ff_mpeg4audio_channels[8]
Definition: mpeg4audio.c:62
int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb)
Definition: mpeg4audio.c:166
static const uint8_t * align_get_bits(GetBitContext *s)
Definition: get_bits.h:449
static av_always_inline unsigned int copy_bits(PutBitContext *pb, GetBitContext *gb, int bits)
Definition: mpeg4audio.c:157
int sbr
-1 implicit, 1 presence
Definition: mpeg4audio.h:34
#define av_always_inline
Definition: attributes.h:37
int ext_sampling_index
Definition: mpeg4audio.h:36
int ps
-1 implicit, 1 presence
Definition: mpeg4audio.h:40
Y Low Complexity.
Definition: mpeg4audio.h:62
bitstream writer API