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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 AVERROR_INVALIDDATA;
37 
38  if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
39  return AVERROR_INVALIDDATA;
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  if (c->sample_rate <= 0) {
46  av_log(NULL, AV_LOG_ERROR, "Invalid sample rate %d\n", c->sample_rate);
47  return AVERROR_INVALIDDATA;
48  }
49 
50  // skip number of samples
51  skip_bits_long(gb, 32);
52 
53  // read number of channels
54  c->chan_config = 0;
55  c->channels = get_bits(gb, 16) + 1;
56 
57  return 0;
58 }
59 
60 /* XXX: make sure to update the copies in the different encoders if you change
61  * this table */
63  96000, 88200, 64000, 48000, 44100, 32000,
64  24000, 22050, 16000, 12000, 11025, 8000, 7350
65 };
66 
68  0, 1, 2, 3, 4, 5, 6, 8
69 };
70 
71 static inline int get_object_type(GetBitContext *gb)
72 {
73  int object_type = get_bits(gb, 5);
74  if (object_type == AOT_ESCAPE)
75  object_type = 32 + get_bits(gb, 6);
76  return object_type;
77 }
78 
79 static inline int get_sample_rate(GetBitContext *gb, int *index)
80 {
81  *index = get_bits(gb, 4);
82  return *index == 0x0f ? get_bits(gb, 24) :
84 }
85 
87  int sync_extension)
88 {
89  int specific_config_bitindex, ret;
90  int start_bit_index = get_bits_count(gb);
93  c->chan_config = get_bits(gb, 4);
96  c->sbr = -1;
97  c->ps = -1;
98  if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
99  // check for W6132 Annex YYYY draft MP3onMP4
100  !(show_bits(gb, 3) & 0x03 && !(show_bits(gb, 9) & 0x3F)))) {
101  if (c->object_type == AOT_PS)
102  c->ps = 1;
104  c->sbr = 1;
106  c->object_type = get_object_type(gb);
107  if (c->object_type == AOT_ER_BSAC)
108  c->ext_chan_config = get_bits(gb, 4);
109  } else {
111  c->ext_sample_rate = 0;
112  }
113  specific_config_bitindex = get_bits_count(gb);
114 
115  if (c->object_type == AOT_ALS) {
116  skip_bits(gb, 5);
117  if (show_bits_long(gb, 24) != MKBETAG('\0','A','L','S'))
118  skip_bits_long(gb, 24);
119 
120  specific_config_bitindex = get_bits_count(gb);
121 
122  ret = parse_config_ALS(gb, c);
123  if (ret < 0)
124  return ret;
125  }
126 
127  if (c->ext_object_type != AOT_SBR && sync_extension) {
128  while (get_bits_left(gb) > 15) {
129  if (show_bits(gb, 11) == 0x2b7) { // sync extension
130  get_bits(gb, 11);
132  if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(gb)) == 1) {
134  if (c->ext_sample_rate == c->sample_rate)
135  c->sbr = -1;
136  }
137  if (get_bits_left(gb) > 11 && get_bits(gb, 11) == 0x548)
138  c->ps = get_bits1(gb);
139  break;
140  } else
141  get_bits1(gb); // skip 1 bit
142  }
143  }
144 
145  //PS requires SBR
146  if (!c->sbr)
147  c->ps = 0;
148  //Limit implicit PS to the HE-AACv2 Profile
149  if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
150  c->ps = 0;
151 
152  return specific_config_bitindex - start_bit_index;
153 }
154 
156  int bit_size, int sync_extension)
157 {
158  GetBitContext gb;
159  int ret;
160 
161  if (bit_size <= 0)
162  return AVERROR_INVALIDDATA;
163 
164  ret = init_get_bits(&gb, buf, bit_size);
165  if (ret < 0)
166  return ret;
167 
168  return ff_mpeg4audio_get_config_gb(c, &gb, sync_extension);
169 }
static unsigned int show_bits_long(GetBitContext *s, int n)
Show 0-32 bits.
Definition: get_bits.h:397
N Parametric Stereo.
Definition: mpeg4audio.h:100
#define NULL
Definition: coverity.c:32
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:261
static void skip_bits_long(GetBitContext *s, int n)
Definition: get_bits.h:204
static int get_sample_rate(GetBitContext *gb, int *index)
Definition: mpeg4audio.c:79
uint8_t
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:199
bitstream reader API header.
Y Escape Value.
Definition: mpeg4audio.h:102
static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)
Parse MPEG-4 audio configuration for ALS object type.
Definition: mpeg4audio.c:33
#define av_log(a,...)
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:587
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int ff_mpeg4audio_get_config_gb(MPEG4AudioConfig *c, GetBitContext *gb, int sync_extension)
Parse MPEG-4 systems extradata from a potentially unaligned GetBitContext to retrieve audio configura...
Definition: mpeg4audio.c:86
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:296
#define FF_ARRAY_ELEMS(a)
void * buf
Definition: avisynth_c.h:690
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:313
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:306
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:425
N Error Resilient Bit-Sliced Arithmetic Coding.
Definition: mpeg4audio.h:93
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:346
static int get_object_type(GetBitContext *gb)
Definition: mpeg4audio.c:71
const int avpriv_mpeg4audio_sample_rates[16]
Definition: mpeg4audio.c:62
Y Spectral Band Replication.
Definition: mpeg4audio.h:79
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 from a raw buffer to retrieve audio configuration. ...
Definition: mpeg4audio.c:155
#define MKBETAG(a, b, c, d)
Definition: common.h:367
Y Audio LosslesS.
Definition: mpeg4audio.h:107
const uint8_t ff_mpeg4audio_channels[8]
Definition: mpeg4audio.c:67
int sbr
-1 implicit, 1 presence
Definition: mpeg4audio.h:38
int ext_sampling_index
Definition: mpeg4audio.h:40
int ps
-1 implicit, 1 presence
Definition: mpeg4audio.h:44
Y Low Complexity.
Definition: mpeg4audio.h:76
bitstream writer API