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 "libavutil/avutil.h"
23 #include "avs2.h"
24 #include "get_bits.h"
25 #include "parser.h"
26 
27 static int avs2_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
28 {
29  int pic_found = pc->frame_start_found;
30  uint32_t state = pc->state;
31  int cur = 0;
32 
33  if (!pic_found) {
34  for (; cur < buf_size; ++cur) {
35  state = (state << 8) | buf[cur];
36  if ((state & 0xFFFFFF00) == 0x100 && AVS2_ISPIC(buf[cur])) {
37  cur++;
38  pic_found = 1;
39  break;
40  }
41  }
42  }
43 
44  if (pic_found) {
45  if (!buf_size)
46  return END_NOT_FOUND;
47  for (; cur < buf_size; cur++) {
48  state = (state << 8) | buf[cur];
49  if ((state & 0xFFFFFF00) == 0x100 && AVS2_ISUNIT(buf[cur])) {
50  pc->frame_start_found = 0;
51  pc->state = -1;
52  return cur - 3;
53  }
54  }
55  }
56 
57  pc->frame_start_found = pic_found;
58  pc->state = state;
59 
60  return END_NOT_FOUND;
61 }
62 
63 static void parse_avs2_seq_header(AVCodecParserContext *s, const uint8_t *buf,
64  int buf_size, AVCodecContext *avctx)
65 {
66  GetBitContext gb;
67  int profile, level;
68  int width, height;
69  int chroma, sample_precision, encoding_precision = 1;
70  // sample_precision and encoding_precision is 3 bits
71  static const uint8_t precision[8] = { 0, 8, 10 };
72  unsigned aspect_ratio;
73  unsigned frame_rate_code;
74  int low_delay;
75  // update buf_size_min if parse more deeper
76  const int buf_size_min = 15;
77 
78  if (buf_size < buf_size_min)
79  return;
80 
81  init_get_bits8(&gb, buf, buf_size_min);
82 
83  s->key_frame = 1;
84  s->pict_type = AV_PICTURE_TYPE_I;
85 
86  profile = get_bits(&gb, 8);
87  level = get_bits(&gb, 8);
88 
89  // progressive_sequence u(1)
90  // field_coded_sequence u(1)
91  skip_bits(&gb, 2);
92 
93  width = get_bits(&gb, 14);
94  height = get_bits(&gb, 14);
95 
96  chroma = get_bits(&gb, 2);
97  sample_precision = get_bits(&gb, 3);
99  encoding_precision = get_bits(&gb, 3);
100 
101  aspect_ratio = get_bits(&gb, 4);
102  frame_rate_code = get_bits(&gb, 4);
103 
104  // bit_rate_lower u(18)
105  // marker_bit f(1)
106  // bit_rate_upper u(12)
107  skip_bits(&gb, 31);
108 
109  low_delay = get_bits(&gb, 1);
110 
111  s->width = width;
112  s->height = height;
113  s->coded_width = FFALIGN(width, 8);
114  s->coded_height = FFALIGN(height, 8);
115  avctx->framerate.num = avctx->time_base.den =
116  ff_avs2_frame_rate_tab[frame_rate_code].num;
117  avctx->framerate.den = avctx->time_base.num =
118  ff_avs2_frame_rate_tab[frame_rate_code].den;
119  avctx->has_b_frames = FFMAX(avctx->has_b_frames, !low_delay);
120 
121  av_log(avctx, AV_LOG_DEBUG,
122  "AVS2 parse seq HDR: profile %x, level %x, "
123  "width %d, height %d, "
124  "chroma %d, sample_precision %d bits, encoding_precision %d bits, "
125  "aspect_ratio 0x%x, framerate %d/%d, low_delay %d\n",
126  profile, level,
127  width, height,
128  chroma, precision[sample_precision], precision[encoding_precision],
129  aspect_ratio, avctx->framerate.num, avctx->framerate.den, low_delay);
130 }
131 
132 static void parse_avs2_units(AVCodecParserContext *s, const uint8_t *buf,
133  int buf_size, AVCodecContext *avctx)
134 {
135  if (buf_size < 5)
136  return;
137 
138  if (!(buf[0] == 0x0 && buf[1] == 0x0 && buf[2] == 0x1))
139  return;
140 
141  switch (buf[3]) {
142  case AVS2_SEQ_START_CODE:
143  parse_avs2_seq_header(s, buf + 4, buf_size - 4, avctx);
144  return;
146  s->key_frame = 1;
147  s->pict_type = AV_PICTURE_TYPE_I;
148  return;
150  s->key_frame = 0;
151  if (buf_size > 9) {
152  int pic_code_type = buf[8] & 0x3;
153  if (pic_code_type == 1)
154  s->pict_type = AV_PICTURE_TYPE_P;
155  else if (pic_code_type == 3)
156  s->pict_type = AV_PICTURE_TYPE_S;
157  else
158  s->pict_type = AV_PICTURE_TYPE_B;
159  }
160  return;
161  }
162 }
163 
165  const uint8_t **poutbuf, int *poutbuf_size,
166  const uint8_t *buf, int buf_size)
167 {
168  ParseContext *pc = s->priv_data;
169  int next;
170 
171  if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
172  next = buf_size;
173  } else {
174  next = avs2_find_frame_end(pc, buf, buf_size);
175  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
176  *poutbuf = NULL;
177  *poutbuf_size = 0;
178  return buf_size;
179  }
180  }
181 
182  parse_avs2_units(s, buf, buf_size, avctx);
183 
184  *poutbuf = buf;
185  *poutbuf_size = buf_size;
186 
187  return next;
188 }
189 
192  .priv_data_size = sizeof(ParseContext),
193  .parser_parse = avs2_parse,
194  .parser_close = ff_parse_close,
195 };
level
uint8_t level
Definition: svq3.c:206
avs2_parse
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:164
ff_parse_close
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:284
AVS2_ISUNIT
#define AVS2_ISUNIT(x)
Definition: avs2.h:41
chroma
static av_always_inline void chroma(WaveformContext *s, AVFrame *in, AVFrame *out, int component, int intensity, int offset_y, int offset_x, int column, int mirror, int jobnr, int nb_jobs)
Definition: vf_waveform.c:1635
AV_CODEC_ID_AVS2
@ AV_CODEC_ID_AVS2
Definition: codec_id.h:244
AVS2_ISPIC
#define AVS2_ISPIC(x)
Definition: avs2.h:40
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
ParseContext::state
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
parse_avs2_units
static void parse_avs2_units(AVCodecParserContext *s, const uint8_t *buf, int buf_size, AVCodecContext *avctx)
Definition: avs2_parser.c:132
skip_bits
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
AVCodecContext::framerate
AVRational framerate
Definition: avcodec.h:1741
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
ParseContext
Definition: parser.h:28
GetBitContext
Definition: get_bits.h:61
AVRational::num
int num
Numerator.
Definition: rational.h:59
init_get_bits8
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:667
AVCodecContext::has_b_frames
int has_b_frames
Size of the frame reordering buffer in the decoder.
Definition: avcodec.h:694
width
#define width
s
#define s(width, name)
Definition: cbs_vp9.c:256
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
get_bits.h
ff_avs2_frame_rate_tab
const AVRational ff_avs2_frame_rate_tab[16]
Definition: avs2.c:25
AVS2_SEQ_START_CODE
@ AVS2_SEQ_START_CODE
Definition: avs2.h:31
AVS2_PROFILE_MAIN10
@ AVS2_PROFILE_MAIN10
Definition: avs2.h:46
NULL
#define NULL
Definition: coverity.c:32
AVS2_INTRA_PIC_START_CODE
@ AVS2_INTRA_PIC_START_CODE
Definition: avs2.h:34
state
static struct @334 state
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
ParseContext::frame_start_found
int frame_start_found
Definition: parser.h:34
AVCodecContext::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avcodec.h:521
AVCodecParser::codec_ids
int codec_ids[7]
Definition: avcodec.h:2960
AVS2_INTER_PIC_START_CODE
@ AVS2_INTER_PIC_START_CODE
Definition: avs2.h:37
height
#define height
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:199
PARSER_FLAG_COMPLETE_FRAMES
#define PARSER_FLAG_COMPLETE_FRAMES
Definition: avcodec.h:2834
parser.h
profile
int profile
Definition: mxfenc.c:2005
AVCodecParserContext
Definition: avcodec.h:2800
AVCodecContext
main external API structure.
Definition: avcodec.h:398
parse_avs2_seq_header
static void parse_avs2_seq_header(AVCodecParserContext *s, const uint8_t *buf, int buf_size, AVCodecContext *avctx)
Definition: avs2_parser.c:63
avs2.h
AV_PICTURE_TYPE_B
@ AV_PICTURE_TYPE_B
Bi-dir predicted.
Definition: avutil.h:276
AVRational::den
int den
Denominator.
Definition: rational.h:60
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:275
avutil.h
END_NOT_FOUND
#define END_NOT_FOUND
Definition: parser.h:40
FFALIGN
#define FFALIGN(x, a)
Definition: macros.h:78
AVCodecParser
Definition: avcodec.h:2959
ff_avs2_parser
const AVCodecParser ff_avs2_parser
Definition: avs2_parser.c:190
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AV_PICTURE_TYPE_S
@ AV_PICTURE_TYPE_S
S(GMC)-VOP MPEG-4.
Definition: avutil.h:277
avs2_find_frame_end
static int avs2_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
Definition: avs2_parser.c:27