FFmpeg  4.4.5
h2645_parse.h
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1 /*
2  * H.264/HEVC 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_H2645_PARSE_H
22 #define AVCODEC_H2645_PARSE_H
23 
24 #include <stdint.h>
25 
26 #include "libavutil/buffer.h"
27 #include "avcodec.h"
28 #include "get_bits.h"
29 
30 #define MAX_MBPAIR_SIZE (256*1024) // a tighter bound could be calculated if someone cares about a few bytes
31 
32 typedef struct H2645NAL {
34 
35  int size;
36  const uint8_t *data;
37 
38  /**
39  * Size, in bits, of just the data, excluding the stop bit and any trailing
40  * padding. I.e. what HEVC calls SODB.
41  */
42  int size_bits;
43 
44  int raw_size;
45  const uint8_t *raw_data;
46 
48 
49  /**
50  * NAL unit type
51  */
52  int type;
53 
54  /**
55  * HEVC only, nuh_temporal_id_plus_1 - 1
56  */
58 
59  /*
60  * HEVC only, identifier of layer to which nal unit belongs
61  */
63 
67  /**
68  * H.264 only, nal_ref_idc
69  */
70  int ref_idc;
71 } H2645NAL;
72 
73 typedef struct H2645RBSP {
78 } H2645RBSP;
79 
80 /* an input packet split into unescaped NAL units */
81 typedef struct H2645Packet {
84  int nb_nals;
86  unsigned nal_buffer_size;
87 } H2645Packet;
88 
89 /**
90  * Extract the raw (unescaped) bitstream.
91  */
92 int ff_h2645_extract_rbsp(const uint8_t *src, int length, H2645RBSP *rbsp,
93  H2645NAL *nal, int small_padding);
94 
95 /**
96  * Split an input packet into NAL units.
97  *
98  * If data == raw_data holds true for a NAL unit of the returned pkt, then
99  * said NAL unit does not contain any emulation_prevention_three_byte and
100  * the data is contained in the input buffer pointed to by buf.
101  * Otherwise, the unescaped data is part of the rbsp_buffer described by the
102  * packet's H2645RBSP.
103  *
104  * If the packet's rbsp_buffer_ref is not NULL, the underlying AVBuffer must
105  * own rbsp_buffer. If not and rbsp_buffer is not NULL, use_ref must be 0.
106  * If use_ref is set, rbsp_buffer will be reference-counted and owned by
107  * the underlying AVBuffer of rbsp_buffer_ref.
108  */
109 int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
110  void *logctx, int is_nalff, int nal_length_size,
111  enum AVCodecID codec_id, int small_padding, int use_ref);
112 
113 /**
114  * Free all the allocated memory in the packet.
115  */
117 
118 static inline int get_nalsize(int nal_length_size, const uint8_t *buf,
119  int buf_size, int *buf_index, void *logctx)
120 {
121  int i, nalsize = 0;
122 
123  if (*buf_index >= buf_size - nal_length_size) {
124  // the end of the buffer is reached, refill it
125  return AVERROR_INVALIDDATA;
126  }
127 
128  for (i = 0; i < nal_length_size; i++)
129  nalsize = ((unsigned)nalsize << 8) | buf[(*buf_index)++];
130  if (nalsize <= 0 || nalsize > buf_size - *buf_index) {
131  av_log(logctx, AV_LOG_ERROR,
132  "Invalid NAL unit size (%d > %d).\n", nalsize, buf_size - *buf_index);
133  return AVERROR_INVALIDDATA;
134  }
135  return nalsize;
136 }
137 
138 #endif /* AVCODEC_H2645_PARSE_H */
uint8_t
Libavcodec external API header.
refcounted data buffer API
bitstream reader API header.
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:46
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length, void *logctx, int is_nalff, int nal_length_size, enum AVCodecID codec_id, int small_padding, int use_ref)
Split an input packet into NAL units.
Definition: h2645_parse.c:392
void ff_h2645_packet_uninit(H2645Packet *pkt)
Free all the allocated memory in the packet.
Definition: h2645_parse.c:523
int ff_h2645_extract_rbsp(const uint8_t *src, int length, H2645RBSP *rbsp, H2645NAL *nal, int small_padding)
Extract the raw (unescaped) bitstream.
Definition: h2645_parse.c:34
static int get_nalsize(int nal_length_size, const uint8_t *buf, int buf_size, int *buf_index, void *logctx)
Definition: h2645_parse.h:118
int i
Definition: input.c:407
A reference to a data buffer.
Definition: buffer.h:84
const uint8_t * data
Definition: h2645_parse.h:36
int ref_idc
H.264 only, nal_ref_idc.
Definition: h2645_parse.h:70
int * skipped_bytes_pos
Definition: h2645_parse.h:66
int raw_size
Definition: h2645_parse.h:44
int size
Definition: h2645_parse.h:35
int nuh_layer_id
Definition: h2645_parse.h:62
int skipped_bytes_pos_size
Definition: h2645_parse.h:65
int type
NAL unit type.
Definition: h2645_parse.h:52
int size_bits
Size, in bits, of just the data, excluding the stop bit and any trailing padding.
Definition: h2645_parse.h:42
int skipped_bytes
Definition: h2645_parse.h:64
GetBitContext gb
Definition: h2645_parse.h:47
int temporal_id
HEVC only, nuh_temporal_id_plus_1 - 1.
Definition: h2645_parse.h:57
const uint8_t * raw_data
Definition: h2645_parse.h:45
uint8_t * rbsp_buffer
Definition: h2645_parse.h:33
H2645NAL * nals
Definition: h2645_parse.h:82
H2645RBSP rbsp
Definition: h2645_parse.h:83
unsigned nal_buffer_size
Definition: h2645_parse.h:86
int nals_allocated
Definition: h2645_parse.h:85
AVBufferRef * rbsp_buffer_ref
Definition: h2645_parse.h:75
int rbsp_buffer_alloc_size
Definition: h2645_parse.h:76
int rbsp_buffer_size
Definition: h2645_parse.h:77
uint8_t * rbsp_buffer
Definition: h2645_parse.h:74
#define av_log(a,...)
#define src
Definition: vp8dsp.c:255
AVPacket * pkt
Definition: movenc.c:59
enum AVCodecID codec_id
Definition: vaapi_decode.c:369