FFmpeg
mjpegbdec.c
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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 
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 
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 
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;
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;
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;
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 
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),
162  .close = ff_mjpeg_decode_end,
164  .capabilities = AV_CODEC_CAP_DR1,
165  .max_lowres = 3,
167 };
AVCodec
AVCodec.
Definition: codec.h:197
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:187
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:41
mjpeg.h
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
SOS
@ SOS
Definition: mjpeg.h:72
SOF0
@ SOF0
Definition: mjpeg.h:39
AVCodecContext::err_recognition
int err_recognition
Error recognition; may misdetect some more or less valid parts as errors.
Definition: avcodec.h:1430
get_bits_long
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:546
mjpegdec.h
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:365
data
const char data[16]
Definition: mxf.c:142
init_get_bits
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:659
skip_bits
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
ff_mjpeg_decode_dht
int ff_mjpeg_decode_dht(MJpegDecodeContext *s)
Definition: mjpegdec.c:236
ff_mjpegb_decoder
const AVCodec ff_mjpegb_decoder
Definition: mjpegbdec.c:155
ff_mjpeg_decode_init
av_cold int ff_mjpeg_decode_init(AVCodecContext *avctx)
Definition: mjpegdec.c:117
GetBitContext
Definition: get_bits.h:61
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
FFMAX3
#define FFMAX3(a, b, c)
Definition: common.h:104
s
#define s(width, name)
Definition: cbs_vp9.c:257
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:202
ff_mjpeg_decode_end
av_cold int ff_mjpeg_decode_end(AVCodecContext *avctx)
Definition: mjpegdec.c:2890
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
NULL
#define NULL
Definition: coverity.c:32
read_offs
static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg)
Definition: mjpegbdec.c:34
ff_mjpeg_decode_dqt
int ff_mjpeg_decode_dqt(MJpegDecodeContext *s)
Definition: mjpegdec.c:195
MJpegDecodeContext
Definition: mjpegdec.h:54
mjpegb_decode_frame
static int mjpegb_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: mjpegbdec.c:43
AV_EF_EXPLODE
#define AV_EF_EXPLODE
abort decoding on minor error detection
Definition: avcodec.h:1441
AV_CODEC_ID_MJPEGB
@ AV_CODEC_ID_MJPEGB
Definition: codec_id.h:57
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:366
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
av_frame_ref
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:326
ff_mjpeg_decode_sos
int ff_mjpeg_decode_sos(MJpegDecodeContext *s, const uint8_t *mb_bitmask, int mb_bitmask_size, const AVFrame *reference)
Definition: mjpegdec.c:1629
size
int size
Definition: twinvq_data.h:10344
MKBETAG
#define MKBETAG(a, b, c, d)
Definition: common.h:479
FFMIN
#define FFMIN(a, b)
Definition: common.h:105
DQT
@ DQT
Definition: mjpeg.h:73
show_bits
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:446
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: internal.h:49
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
DHT
@ DHT
Definition: mjpeg.h:56
avcodec.h
ret
ret
Definition: filter_design.txt:187
FF_DEBUG_QP
#define FF_DEBUG_QP
Definition: avcodec.h:1413
AVCodecContext
main external API structure.
Definition: avcodec.h:501
AVCodecContext::debug
int debug
debug
Definition: avcodec.h:1408
ff_mjpeg_decode_sof
int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
Definition: mjpegdec.c:297
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:528
AVPacket
This structure stores compressed data.
Definition: packet.h:342
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59