FFmpeg
avs2_parser.c
Go to the documentation of this file.
1 /*
2  * AVS2-P2/IEEE1857.4 video parser.
3  * Copyright (c) 2018 Huiwen Ren <hwrenx@gmail.com>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "parser.h"
23 
24 #define SLICE_MAX_START_CODE 0x000001af
25 
26 #define ISPIC(x) ((x) == 0xB3 || (x) == 0xB6)
27 #define ISUNIT(x) ((x) == 0xB0 || (x) == 0xB1 || (x) == 0xB2 || ISPIC(x))
28 
29 static int avs2_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
30 {
31  int pic_found = pc->frame_start_found;
32  uint32_t state = pc->state;
33  int cur = 0;
34 
35  if (!pic_found) {
36  for (; cur < buf_size; ++cur) {
37  state = (state<<8) | buf[cur];
38  if (ISUNIT(buf[cur])){
39  ++cur;
40  pic_found = 1;
41  break;
42  }
43  }
44  }
45 
46  if (pic_found) {
47  if (!buf_size)
48  return END_NOT_FOUND;
49  for (; cur < buf_size; ++cur) {
50  state = (state << 8) | buf[cur];
51  if ((state & 0xFFFFFF00) == 0x100 && state > SLICE_MAX_START_CODE) {
52  pc->frame_start_found = 0;
53  pc->state = -1;
54  return cur - 3;
55  }
56  }
57  }
58 
59  pc->frame_start_found = pic_found;
60  pc->state = state;
61 
62  return END_NOT_FOUND;
63 }
64 
66  const uint8_t **poutbuf, int *poutbuf_size,
67  const uint8_t *buf, int buf_size)
68 {
69  ParseContext *pc = s->priv_data;
70  int next;
71 
73  next = buf_size;
74  } else {
75  next = avs2_find_frame_end(pc, buf, buf_size);
76  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
77  *poutbuf = NULL;
78  *poutbuf_size = 0;
79  return buf_size;
80  }
81  }
82 
83  *poutbuf = buf;
84  *poutbuf_size = buf_size;
85 
86  return next;
87 }
88 
91  .priv_data_size = sizeof(ParseContext),
92  .parser_parse = avs2_parse,
93  .parser_close = ff_parse_close,
95 };
#define NULL
Definition: coverity.c:32
int codec_ids[5]
Definition: avcodec.h:5276
int frame_start_found
Definition: parser.h:34
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:322
static struct @315 state
#define SLICE_MAX_START_CODE
Definition: avs2_parser.c:24
uint8_t
AVCodecParser ff_avs2_parser
Definition: avs2_parser.c:89
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
Definition: parser.c:234
static char * split(char *message, char delim)
Definition: af_channelmap.c:81
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:315
#define s(width, name)
Definition: cbs_vp9.c:257
main external API structure.
Definition: avcodec.h:1565
void * buf
Definition: avisynth_c.h:766
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
#define END_NOT_FOUND
Definition: parser.h:40
static int avs2_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
Definition: avs2_parser.c:29
static int avs2_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: avs2_parser.c:65
#define PARSER_FLAG_COMPLETE_FRAMES
Definition: avcodec.h:5142
#define ISUNIT(x)
Definition: avs2_parser.c:27