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av1_parse.h
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1 /*
2  * AV1 common parsing code
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVCODEC_AV1_PARSE_H
22 #define AVCODEC_AV1_PARSE_H
23 
24 #include <stdint.h>
25 
26 #include "av1.h"
27 #include "avcodec.h"
28 #include "get_bits.h"
29 
30 typedef struct AV1OBU {
31  /** Size of payload */
32  int size;
33  const uint8_t *data;
34 
35  /**
36  * Size, in bits, of just the data, excluding the trailing_one_bit and
37  * any trailing padding.
38  */
39  int size_bits;
40 
41  /** Size of entire OBU, including header */
42  int raw_size;
43  const uint8_t *raw_data;
44 
45  /** GetBitContext initialized to the start of the payload */
47 
48  int type;
49 
52 } AV1OBU;
53 
54 /** An input packet split into OBUs */
55 typedef struct AV1Packet {
57  int nb_obus;
59 } AV1Packet;
60 
61 /**
62  * Extract an OBU from a raw bitstream.
63  *
64  * @note This function does not copy or store any bitstream data. All
65  * the pointers in the AV1OBU structure will be valid as long
66  * as the input buffer also is.
67  */
68 int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length,
69  void *logctx);
70 
71 /**
72  * Split an input packet into OBUs.
73  *
74  * @note This function does not copy or store any bitstream data. All
75  * the pointers in the AV1Packet structure will be valid as
76  * long as the input buffer also is.
77  */
79  void *logctx);
80 
81 /**
82  * Free all the allocated memory in the packet.
83  */
85 
86 static inline int64_t leb128(GetBitContext *gb) {
87  int64_t ret = 0;
88  int i;
89 
90  for (i = 0; i < 8; i++) {
91  int byte = get_bits(gb, 8);
92  ret |= (int64_t)(byte & 0x7f) << (i * 7);
93  if (!(byte & 0x80))
94  break;
95  }
96  return ret;
97 }
98 
99 static inline int parse_obu_header(const uint8_t *buf, int buf_size,
100  int64_t *obu_size, int *start_pos, int *type,
101  int *temporal_id, int *spatial_id)
102 {
103  GetBitContext gb;
104  int ret, extension_flag, has_size_flag;
105  int64_t size;
106 
107  ret = init_get_bits8(&gb, buf, FFMIN(buf_size, 2 + 8)); // OBU header fields + max leb128 length
108  if (ret < 0)
109  return ret;
110 
111  if (get_bits1(&gb) != 0) // obu_forbidden_bit
112  return AVERROR_INVALIDDATA;
113 
114  *type = get_bits(&gb, 4);
115  extension_flag = get_bits1(&gb);
116  has_size_flag = get_bits1(&gb);
117  skip_bits1(&gb); // obu_reserved_1bit
118 
119  if (extension_flag) {
120  *temporal_id = get_bits(&gb, 3);
121  *spatial_id = get_bits(&gb, 2);
122  skip_bits(&gb, 3); // extension_header_reserved_3bits
123  } else {
124  *temporal_id = *spatial_id = 0;
125  }
126 
127  *obu_size = has_size_flag ? leb128(&gb)
128  : buf_size - 1 - extension_flag;
129 
130  if (get_bits_left(&gb) < 0)
131  return AVERROR_INVALIDDATA;
132 
133  *start_pos = get_bits_count(&gb) / 8;
134 
135  size = *obu_size + *start_pos;
136 
137  if (size > buf_size)
138  return AVERROR_INVALIDDATA;
139 
140  return size;
141 }
142 
143 static inline int get_obu_bit_length(const uint8_t *buf, int size, int type)
144 {
145  int v;
146 
147  /* There are no trailing bits on these */
148  if (type == AV1_OBU_TILE_GROUP || type == AV1_OBU_FRAME) {
149  if (size > INT_MAX / 8)
150  return AVERROR(ERANGE);
151  else
152  return size * 8;
153  }
154 
155  while (size > 0 && buf[size - 1] == 0)
156  size--;
157 
158  if (!size)
159  return 0;
160 
161  v = buf[size - 1];
162 
163  if (size > INT_MAX / 8)
164  return AVERROR(ERANGE);
165  size *= 8;
166 
167  /* Remove the trailing_one_bit and following trailing zeros */
168  if (v)
169  size -= ff_ctz(v) + 1;
170 
171  return size;
172 }
173 
174 #endif /* AVCODEC_AV1_PARSE_H */
int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length, void *logctx)
Extract an OBU from a raw bitstream.
Definition: av1_parse.c:29
#define ff_ctz
Definition: intmath.h:106
#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:381
const uint8_t * raw_data
Definition: av1_parse.h:43
int spatial_id
Definition: av1_parse.h:51
static AVPacket pkt
const uint8_t * data
Definition: av1_parse.h:33
uint8_t
int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length, void *logctx)
Split an input packet into OBUs.
Definition: av1_parse.c:56
int size
Size of payload.
Definition: av1_parse.h:32
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:219
bitstream reader API header.
ptrdiff_t size
Definition: opengl_enc.c:101
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:814
#define AVERROR(e)
Definition: error.h:43
GetBitContext gb
GetBitContext initialized to the start of the payload.
Definition: av1_parse.h:46
GLsizei GLsizei * length
Definition: opengl_enc.c:115
#define FFMIN(a, b)
Definition: common.h:96
int temporal_id
Definition: av1_parse.h:50
static int parse_obu_header(const uint8_t *buf, int buf_size, int64_t *obu_size, int *start_pos, int *type, int *temporal_id, int *spatial_id)
Definition: av1_parse.h:99
int nb_obus
Definition: av1_parse.h:57
AV1OBU * obus
Definition: av1_parse.h:56
Libavcodec external API header.
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_WB16 unsigned int_TMPL byte
Definition: bytestream.h:87
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:650
void * buf
Definition: avisynth_c.h:690
AV1 common definitions.
GLint GLenum type
Definition: opengl_enc.c:105
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:487
static void skip_bits1(GetBitContext *s)
Definition: get_bits.h:523
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:460
int type
Definition: av1_parse.h:48
int obus_allocated
Definition: av1_parse.h:58
int size_bits
Size, in bits, of just the data, excluding the trailing_one_bit and any trailing padding.
Definition: av1_parse.h:39
An input packet split into OBUs.
Definition: av1_parse.h:55
int raw_size
Size of entire OBU, including header.
Definition: av1_parse.h:42
static int64_t leb128(GetBitContext *gb)
Definition: av1_parse.h:86
static int get_obu_bit_length(const uint8_t *buf, int size, int type)
Definition: av1_parse.h:143
void ff_av1_packet_uninit(AV1Packet *pkt)
Free all the allocated memory in the packet.
Definition: av1_parse.c:103