path: root/libavcodec/h2645_parse.h (plain)
blob: 5f3e17a0f258b14355d798db902eafdd68ef446a

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 "avcodec.h"
27	#include "get_bits.h"
28
29	#define MAX_MBPAIR_SIZE (256*1024) // a tighter bound could be calculated if someone cares about a few bytes
30
31	typedef struct H2645NAL {
32	uint8_t *rbsp_buffer;
33	int rbsp_buffer_size;
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	int skipped_bytes;
60	int skipped_bytes_pos_size;
61	int *skipped_bytes_pos;
62	/**
63	* H.264 only, nal_ref_idc
64	*/
65	int ref_idc;
66	} H2645NAL;
67
68	/* an input packet split into unescaped NAL units */
69	typedef struct H2645Packet {
70	H2645NAL *nals;
71	int nb_nals;
72	int nals_allocated;
73	} H2645Packet;
74
75	/**
76	* Extract the raw (unescaped) bitstream.
77	*/
78	int ff_h2645_extract_rbsp(const uint8_t *src, int length,
79	H2645NAL *nal, int small_padding);
80
81	/**
82	* Split an input packet into NAL units.
83	*/
84	int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
85	void *logctx, int is_nalff, int nal_length_size,
86	enum AVCodecID codec_id, int small_padding);
87
88	/**
89	* Free all the allocated memory in the packet.
90	*/
91	void ff_h2645_packet_uninit(H2645Packet *pkt);
92
93	static inline int get_nalsize(int nal_length_size, const uint8_t *buf,
94	int buf_size, int *buf_index, void *logctx)
95	{
96	int i, nalsize = 0;
97
98	if (*buf_index >= buf_size - nal_length_size) {
99	// the end of the buffer is reached, refill it
100	return AVERROR(EAGAIN);
101	}
102
103	for (i = 0; i < nal_length_size; i++)
104	nalsize = ((unsigned)nalsize << 8) | buf[(*buf_index)++];
105	if (nalsize <= 0 || nalsize > buf_size - *buf_index) {
106	av_log(logctx, AV_LOG_ERROR,
107	"Invalid NAL unit size (%d > %d).\n", nalsize, buf_size - *buf_index);
108	return AVERROR_INVALIDDATA;
109	}
110	return nalsize;
111	}
112
113	#endif /* AVCODEC_H2645_PARSE_H */
114