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 {
33 uint8_t *rbsp_buffer;
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
47 GetBitContext gb;
48
49 /**
50 * NAL unit type
51 */
52 int type;
53
54 /**
55 * HEVC only, nuh_temporal_id_plus_1 - 1
56 */
57 int temporal_id;
58
59 /*
60 * HEVC only, identifier of layer to which nal unit belongs
61 */
62 int nuh_layer_id;
63
64 int skipped_bytes;
65 int skipped_bytes_pos_size;
66 int *skipped_bytes_pos;
67 /**
68 * H.264 only, nal_ref_idc
69 */
70 int ref_idc;
71 } H2645NAL;
72
73 typedef struct H2645RBSP {
74 uint8_t *rbsp_buffer;
75 AVBufferRef *rbsp_buffer_ref;
76 int rbsp_buffer_alloc_size;
77 int rbsp_buffer_size;
78 } H2645RBSP;
79
80 /* an input packet split into unescaped NAL units */
81 typedef struct H2645Packet {
82 H2645NAL *nals;
83 H2645RBSP rbsp;
84 int nb_nals;
85 int nals_allocated;
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 */
116 void ff_h2645_packet_uninit(H2645Packet *pkt);
117
get_nalsize(int nal_length_size,const uint8_t * buf,int buf_size,int * buf_index,void * logctx)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(EAGAIN);
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 */
139