FFmpeg  4.2.1
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 
62  /**
63  * H.264 only, nal_ref_idc
64  */
65  int ref_idc;
66 } H2645NAL;
67 
68 typedef struct H2645RBSP {
73 } H2645RBSP;
74 
75 /* an input packet split into unescaped NAL units */
76 typedef struct H2645Packet {
79  int nb_nals;
81 } H2645Packet;
82 
83 /**
84  * Extract the raw (unescaped) bitstream.
85  */
86 int ff_h2645_extract_rbsp(const uint8_t *src, int length, H2645RBSP *rbsp,
87  H2645NAL *nal, int small_padding);
88 
89 /**
90  * Split an input packet into NAL units.
91  *
92  * If data == raw_data holds true for a NAL unit of the returned pkt, then
93  * said NAL unit does not contain any emulation_prevention_three_byte and
94  * the data is contained in the input buffer pointed to by buf.
95  * Otherwise, the unescaped data is part of the rbsp_buffer described by the
96  * packet's H2645RBSP.
97  *
98  * If the packet's rbsp_buffer_ref is not NULL, the underlying AVBuffer must
99  * own rbsp_buffer. If not and rbsp_buffer is not NULL, use_ref must be 0.
100  * If use_ref is set, rbsp_buffer will be reference-counted and owned by
101  * the underlying AVBuffer of rbsp_buffer_ref.
102  */
104  void *logctx, int is_nalff, int nal_length_size,
105  enum AVCodecID codec_id, int small_padding, int use_ref);
106 
107 /**
108  * Free all the allocated memory in the packet.
109  */
111 
112 static inline int get_nalsize(int nal_length_size, const uint8_t *buf,
113  int buf_size, int *buf_index, void *logctx)
114 {
115  int i, nalsize = 0;
116 
117  if (*buf_index >= buf_size - nal_length_size) {
118  // the end of the buffer is reached, refill it
119  return AVERROR(EAGAIN);
120  }
121 
122  for (i = 0; i < nal_length_size; i++)
123  nalsize = ((unsigned)nalsize << 8) | buf[(*buf_index)++];
124  if (nalsize <= 0 || nalsize > buf_size - *buf_index) {
125  av_log(logctx, AV_LOG_ERROR,
126  "Invalid NAL unit size (%d > %d).\n", nalsize, buf_size - *buf_index);
127  return AVERROR_INVALIDDATA;
128  }
129  return nalsize;
130 }
131 
132 #endif /* AVCODEC_H2645_PARSE_H */
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int size
Definition: h2645_parse.h:35
enum AVCodecID codec_id
Definition: qsv.c:72
static AVPacket pkt
#define src
Definition: vp8dsp.c:254
int size_bits
Size, in bits, of just the data, excluding the stop bit and any trailing padding. ...
Definition: h2645_parse.h:42
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
int skipped_bytes_pos_size
Definition: h2645_parse.h:60
uint8_t
bitstream reader API header.
#define av_log(a,...)
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:215
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int * skipped_bytes_pos
Definition: h2645_parse.h:61
#define AVERROR(e)
Definition: error.h:43
void ff_h2645_packet_uninit(H2645Packet *pkt)
Free all the allocated memory in the packet.
Definition: h2645_parse.c:517
int raw_size
Definition: h2645_parse.h:44
static int get_nalsize(int nal_length_size, const uint8_t *buf, int buf_size, int *buf_index, void *logctx)
Definition: h2645_parse.h:112
int ref_idc
H.264 only, nal_ref_idc.
Definition: h2645_parse.h:65
int type
NAL unit type.
Definition: h2645_parse.h:52
Libavcodec external API header.
int nals_allocated
Definition: h2645_parse.h:80
AVBufferRef * rbsp_buffer_ref
Definition: h2645_parse.h:70
const uint8_t * data
Definition: h2645_parse.h:36
void * buf
Definition: avisynth_c.h:766
int rbsp_buffer_size
Definition: h2645_parse.h:72
int rbsp_buffer_alloc_size
Definition: h2645_parse.h:71
uint8_t * rbsp_buffer
Definition: h2645_parse.h:69
refcounted data buffer API
H2645RBSP rbsp
Definition: h2645_parse.h:78
A reference to a data buffer.
Definition: buffer.h:81
int skipped_bytes
Definition: h2645_parse.h:59
GetBitContext gb
Definition: h2645_parse.h:47
const uint8_t * raw_data
Definition: h2645_parse.h:45
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:393
H2645NAL * nals
Definition: h2645_parse.h:77
int temporal_id
HEVC only, nuh_temporal_id_plus_1 - 1.
Definition: h2645_parse.h:57
uint8_t * rbsp_buffer
Definition: h2645_parse.h:33
const char int length
Definition: avisynth_c.h:860