1 /*
2 * Apple MJPEG-B decoder
3 * Copyright (c) 2002 Alex Beregszaszi
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 * @file
24 * Apple MJPEG-B decoder.
25 */
26
27 #include <inttypes.h>
28
29 #include "avcodec.h"
30 #include "internal.h"
31 #include "mjpeg.h"
32 #include "mjpegdec.h"
33
read_offs(AVCodecContext * avctx,GetBitContext * gb,uint32_t size,const char * err_msg)34 static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg){
35 uint32_t offs= get_bits_long(gb, 32);
36 if(offs >= size){
37 av_log(avctx, AV_LOG_WARNING, err_msg, offs, size);
38 return 0;
39 }
40 return offs;
41 }
42
mjpegb_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)43 static int mjpegb_decode_frame(AVCodecContext *avctx,
44 void *data, int *got_frame,
45 AVPacket *avpkt)
46 {
47 const uint8_t *buf = avpkt->data;
48 int buf_size = avpkt->size;
49 MJpegDecodeContext *s = avctx->priv_data;
50 const uint8_t *buf_end, *buf_ptr;
51 GetBitContext hgb; /* for the header */
52 uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs;
53 uint32_t field_size, sod_offs;
54 int ret;
55
56 buf_ptr = buf;
57 buf_end = buf + buf_size;
58 s->got_picture = 0;
59 s->adobe_transform = -1;
60
61 read_header:
62 /* reset on every SOI */
63 s->restart_interval = 0;
64 s->restart_count = 0;
65 s->mjpb_skiptosod = 0;
66
67 if (buf_end - buf_ptr >= 1 << 28)
68 return AVERROR_INVALIDDATA;
69
70 init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8);
71
72 skip_bits(&hgb, 32); /* reserved zeros */
73
74 if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g')) {
75 av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n");
76 return AVERROR_INVALIDDATA;
77 }
78
79 field_size = get_bits_long(&hgb, 32); /* field size */
80 av_log(avctx, AV_LOG_DEBUG, "field size: 0x%"PRIx32"\n", field_size);
81 skip_bits(&hgb, 32); /* padded field size */
82 second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n");
83 av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%"PRIx32"\n",
84 second_field_offs);
85
86 dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n");
87 av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%"PRIx32"\n", dqt_offs);
88 if (dqt_offs) {
89 init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8);
90 s->start_code = DQT;
91 ret = ff_mjpeg_decode_dqt(s);
92 if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
93 return ret;
94 }
95
96 dht_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dht is %d and size is %d\n");
97 av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%"PRIx32"\n", dht_offs);
98 if (dht_offs) {
99 init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8);
100 s->start_code = DHT;
101 ff_mjpeg_decode_dht(s);
102 }
103
104 sof_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
105 av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%"PRIx32"\n", sof_offs);
106 if (sof_offs) {
107 init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8);
108 s->start_code = SOF0;
109 if ((ret = ff_mjpeg_decode_sof(s)) < 0)
110 return ret;
111 }
112
113 sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n");
114 av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%"PRIx32"\n", sos_offs);
115 sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
116 av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%"PRIx32"\n", sod_offs);
117 if (sos_offs) {
118 init_get_bits(&s->gb, buf_ptr + sos_offs,
119 8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs));
120 s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16));
121 s->start_code = SOS;
122 ret = ff_mjpeg_decode_sos(s, NULL, 0, NULL);
123 if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
124 return ret;
125 }
126
127 if (s->interlaced) {
128 s->bottom_field ^= 1;
129 /* if not bottom field, do not output image yet */
130 if (s->bottom_field != s->interlace_polarity && second_field_offs) {
131 buf_ptr = buf + second_field_offs;
132 goto read_header;
133 }
134 }
135
136 //XXX FIXME factorize, this looks very similar to the EOI code
137
138 if(!s->got_picture) {
139 av_log(avctx, AV_LOG_WARNING, "no picture\n");
140 return buf_size;
141 }
142
143 if ((ret = av_frame_ref(data, s->picture_ptr)) < 0)
144 return ret;
145 *got_frame = 1;
146
147 if (!s->lossless && avctx->debug & FF_DEBUG_QP) {
148 av_log(avctx, AV_LOG_DEBUG, "QP: %d\n",
149 FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2]));
150 }
151
152 return buf_size;
153 }
154
155 AVCodec ff_mjpegb_decoder = {
156 .name = "mjpegb",
157 .long_name = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"),
158 .type = AVMEDIA_TYPE_VIDEO,
159 .id = AV_CODEC_ID_MJPEGB,
160 .priv_data_size = sizeof(MJpegDecodeContext),
161 .init = ff_mjpeg_decode_init,
162 .close = ff_mjpeg_decode_end,
163 .decode = mjpegb_decode_frame,
164 .capabilities = AV_CODEC_CAP_DR1,
165 .max_lowres = 3,
166 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
167 };
168