1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/*
* Apple MJPEG-B decoder
* Copyright (c) 2002 Alex Beregszaszi
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file libavcodec/mjpegbdec.c
* Apple MJPEG-B decoder.
*/
#include "avcodec.h"
#include "mjpeg.h"
#include "mjpegdec.h"
static int mjpegb_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *buf, int buf_size)
{
MJpegDecodeContext *s = avctx->priv_data;
const uint8_t *buf_end, *buf_ptr;
AVFrame *picture = data;
GetBitContext hgb; /* for the header */
uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs;
uint32_t field_size, sod_offs;
buf_ptr = buf;
buf_end = buf + buf_size;
read_header:
/* reset on every SOI */
s->restart_interval = 0;
s->restart_count = 0;
s->mjpb_skiptosod = 0;
init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8);
skip_bits(&hgb, 32); /* reserved zeros */
if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g'))
{
av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n");
return 0;
}
field_size = get_bits_long(&hgb, 32); /* field size */
av_log(avctx, AV_LOG_DEBUG, "field size: 0x%x\n", field_size);
skip_bits(&hgb, 32); /* padded field size */
second_field_offs = get_bits_long(&hgb, 32);
av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%x\n", second_field_offs);
dqt_offs = get_bits_long(&hgb, 32);
av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%x\n", dqt_offs);
if (dqt_offs)
{
init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8);
s->start_code = DQT;
ff_mjpeg_decode_dqt(s);
}
dht_offs = get_bits_long(&hgb, 32);
av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%x\n", dht_offs);
if (dht_offs)
{
init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8);
s->start_code = DHT;
ff_mjpeg_decode_dht(s);
}
sof_offs = get_bits_long(&hgb, 32);
av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%x\n", sof_offs);
if (sof_offs)
{
init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8);
s->start_code = SOF0;
if (ff_mjpeg_decode_sof(s) < 0)
return -1;
}
sos_offs = get_bits_long(&hgb, 32);
av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%x\n", sos_offs);
sod_offs = get_bits_long(&hgb, 32);
av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%x\n", sod_offs);
if (sos_offs)
{
// init_get_bits(&s->gb, buf+sos_offs, (buf_end - (buf+sos_offs))*8);
init_get_bits(&s->gb, buf_ptr+sos_offs, field_size*8);
s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16));
s->start_code = SOS;
ff_mjpeg_decode_sos(s);
}
if (s->interlaced) {
s->bottom_field ^= 1;
/* if not bottom field, do not output image yet */
if (s->bottom_field != s->interlace_polarity && second_field_offs)
{
buf_ptr = buf + second_field_offs;
second_field_offs = 0;
goto read_header;
}
}
//XXX FIXME factorize, this looks very similar to the EOI code
*picture= s->picture;
*data_size = sizeof(AVFrame);
if(!s->lossless){
picture->quality= FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2]);
picture->qstride= 0;
picture->qscale_table= s->qscale_table;
memset(picture->qscale_table, picture->quality, (s->width+15)/16);
if(avctx->debug & FF_DEBUG_QP)
av_log(avctx, AV_LOG_DEBUG, "QP: %d\n", picture->quality);
picture->quality*= FF_QP2LAMBDA;
}
return buf_ptr - buf;
}
AVCodec mjpegb_decoder = {
"mjpegb",
CODEC_TYPE_VIDEO,
CODEC_ID_MJPEGB,
sizeof(MJpegDecodeContext),
ff_mjpeg_decode_init,
NULL,
ff_mjpeg_decode_end,
mjpegb_decode_frame,
CODEC_CAP_DR1,
NULL,
.long_name = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"),
};
|
