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 AVS2_SLICE_MAX_START_CODE 0x000001AF
25
26 #define AVS2_ISPIC(x) ((x) == 0xB3 || (x) == 0xB6)
27 #define AVS2_ISUNIT(x) ((x) == 0xB0 || (x) == 0xB1 || (x) == 0xB2 || AVS2_ISPIC(x))
28
avs2_find_frame_end(ParseContext * pc,const uint8_t * buf,int buf_size)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 (AVS2_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 > AVS2_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
avs2_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)65 static int avs2_parse(AVCodecParserContext *s, AVCodecContext *avctx,
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
72 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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
89 AVCodecParser ff_avs2_parser = {
90 .codec_ids = { AV_CODEC_ID_AVS2 },
91 .priv_data_size = sizeof(ParseContext),
92 .parser_parse = avs2_parse,
93 .parser_close = ff_parse_close,
94 .split = ff_mpeg4video_split,
95 };
96