FFmpeg
dnxuc_parser.c
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1 /*
2  * Avid DNxUncomressed / SMPTE RDD 50 parser
3  * Copyright (c) 2024 Martin Schitter
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 /*
23  * This parser for DNxUncompressed video data is mostly based on the public
24  * SMPTE RDD 50:2019 specification.
25  */
26 
27 #include "parser.h"
28 #include "libavutil/bswap.h"
29 
30 typedef struct DNxUcParseContext {
32  uint32_t remaining;
34 
36  AVCodecContext *avctx,
37  const uint8_t **poutbuf, int *poutbuf_size,
38  const uint8_t *buf, int buf_size)
39 {
40  DNxUcParseContext *ipc = s->priv_data;
41  int next = END_NOT_FOUND;
42 
43  s->pict_type = AV_PICTURE_TYPE_NONE;
44 
45  *poutbuf_size = 0;
46  *poutbuf = NULL;
47 
48  if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
49  next = buf_size;
50  } else {
51  if (ipc->remaining == 0) {
52  uint64_t state = ipc->pc.state64;
53  for (int i = 0; i < buf_size; i++) {
54  state = (state << 8) | buf[i];
55  if (ipc->pc.index + i >= 7 && (uint32_t)state == MKBETAG('p','a','c','k')) {
56  uint32_t size = av_bswap32(state >> 32);
57  if (size >= 8) {
58  next = i - 7;
59  ipc->remaining = size + FFMIN(next, 0);
60  break;
61  }
62  }
63  }
64  ipc->pc.state64 = state;
65  } else if (ipc->remaining <= buf_size) {
66  next = ipc->remaining;
67  ipc->remaining = 0;
68  } else {
69  ipc->remaining -= buf_size;
70  }
71  if (ff_combine_frame(&ipc->pc, next, &buf, &buf_size) < 0) {
72  *poutbuf = NULL;
73  *poutbuf_size = 0;
74  return buf_size;
75  }
76  }
77 
78  *poutbuf = buf;
79  *poutbuf_size = buf_size;
80 
81  return next;
82 }
83 
86  .priv_data_size = sizeof(DNxUcParseContext),
87  .parser_parse = dnxuc_parse,
88 };
DNxUcParseContext::pc
ParseContext pc
Definition: dnxuc_parser.c:31
ff_dnxuc_parser
const AVCodecParser ff_dnxuc_parser
Definition: dnxuc_parser.c:84
ParseContext
Definition: parser.h:28
dnxuc_parse
static int dnxuc_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: dnxuc_parser.c:35
ParseContext::index
int index
Definition: parser.h:30
s
#define s(width, name)
Definition: cbs_vp9.c:198
NULL
#define NULL
Definition: coverity.c:32
AVCodecParser::codec_ids
int codec_ids[7]
Definition: avcodec.h:2908
av_bswap32
#define av_bswap32
Definition: bswap.h:47
size
int size
Definition: twinvq_data.h:10344
MKBETAG
#define MKBETAG(a, b, c, d)
Definition: macros.h:56
DNxUcParseContext::remaining
uint32_t remaining
Definition: dnxuc_parser.c:32
AV_PICTURE_TYPE_NONE
@ AV_PICTURE_TYPE_NONE
Undefined.
Definition: avutil.h:278
ff_combine_frame
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:203
PARSER_FLAG_COMPLETE_FRAMES
#define PARSER_FLAG_COMPLETE_FRAMES
Definition: avcodec.h:2782
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
state
static struct @465 state
parser.h
DNxUcParseContext
Definition: dnxuc_parser.c:30
AVCodecParserContext
Definition: avcodec.h:2748
bswap.h
AVCodecContext
main external API structure.
Definition: avcodec.h:451
ParseContext::state64
uint64_t state64
contains the last 8 bytes in MSB order
Definition: parser.h:37
END_NOT_FOUND
#define END_NOT_FOUND
Definition: parser.h:40
AV_CODEC_ID_DNXUC
@ AV_CODEC_ID_DNXUC
Definition: codec_id.h:329
AVCodecParser
Definition: avcodec.h:2907