Libav
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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
27 #include <inttypes.h>
28 
29 #include "avcodec.h"
30 #include "mjpeg.h"
31 #include "mjpegdec.h"
32 
33 static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg){
34  uint32_t offs= get_bits_long(gb, 32);
35  if(offs >= size){
36  av_log(avctx, AV_LOG_WARNING, err_msg, offs, size);
37  return 0;
38  }
39  return offs;
40 }
41 
43  void *data, int *got_frame,
44  AVPacket *avpkt)
45 {
46  const uint8_t *buf = avpkt->data;
47  int buf_size = avpkt->size;
48  MJpegDecodeContext *s = avctx->priv_data;
49  const uint8_t *buf_end, *buf_ptr;
50  GetBitContext hgb; /* for the header */
51  uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs;
52  uint32_t field_size, sod_offs;
53  int ret;
54 
55  buf_ptr = buf;
56  buf_end = buf + buf_size;
57 
59  /* reset on every SOI */
60  s->restart_interval = 0;
61  s->restart_count = 0;
62  s->mjpb_skiptosod = 0;
63 
64  if (buf_end - buf_ptr >= 1 << 28)
65  return AVERROR_INVALIDDATA;
66 
67  init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8);
68 
69  skip_bits(&hgb, 32); /* reserved zeros */
70 
71  if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g'))
72  {
73  av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n");
74  return AVERROR_INVALIDDATA;
75  }
76 
77  field_size = get_bits_long(&hgb, 32); /* field size */
78  av_log(avctx, AV_LOG_DEBUG, "field size: 0x%"PRIx32"\n", field_size);
79  skip_bits(&hgb, 32); /* padded field size */
80  second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n");
81  av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%"PRIx32"\n",
82  second_field_offs);
83 
84  dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n");
85  av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%"PRIx32"\n", dqt_offs);
86  if (dqt_offs)
87  {
88  init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8);
89  s->start_code = DQT;
90  if (ff_mjpeg_decode_dqt(s) < 0 &&
91  (avctx->err_recognition & AV_EF_EXPLODE))
92  return AVERROR_INVALIDDATA;
93  }
94 
95  dht_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dht is %d and size is %d\n");
96  av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%"PRIx32"\n", dht_offs);
97  if (dht_offs)
98  {
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  {
108  init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8);
109  s->start_code = SOF0;
110  if (ff_mjpeg_decode_sof(s) < 0)
111  return -1;
112  }
113 
114  sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n");
115  av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%"PRIx32"\n", sos_offs);
116  sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
117  av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%"PRIx32"\n", sod_offs);
118  if (sos_offs)
119  {
120  init_get_bits(&s->gb, buf_ptr + sos_offs,
121  8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs));
122  s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16));
123  s->start_code = SOS;
124  if (ff_mjpeg_decode_sos(s, NULL, NULL) < 0 &&
125  (avctx->err_recognition & AV_EF_EXPLODE))
126  return AVERROR_INVALIDDATA;
127  }
128 
129  if (s->interlaced) {
130  s->bottom_field ^= 1;
131  /* if not bottom field, do not output image yet */
132  if (s->bottom_field != s->interlace_polarity && second_field_offs)
133  {
134  buf_ptr = buf + second_field_offs;
135  second_field_offs = 0;
136  goto read_header;
137  }
138  }
139 
140  //XXX FIXME factorize, this looks very similar to the EOI code
141 
142  if ((ret = av_frame_ref(data, s->picture_ptr)) < 0)
143  return ret;
144  *got_frame = 1;
145 
146  if (!s->lossless && avctx->debug & FF_DEBUG_QP) {
147  av_log(avctx, AV_LOG_DEBUG, "QP: %d\n",
148  FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2]));
149  }
150 
151  return buf_size;
152 }
153 
155  .name = "mjpegb",
156  .long_name = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"),
157  .type = AVMEDIA_TYPE_VIDEO,
158  .id = AV_CODEC_ID_MJPEGB,
159  .priv_data_size = sizeof(MJpegDecodeContext),
163  .capabilities = CODEC_CAP_DR1,
164 };
#define FFMAX3(a, b, c)
Definition: common.h:56
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:54
int size
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:129
int ff_mjpeg_decode_dqt(MJpegDecodeContext *s)
Definition: mjpegdec.c:134
int qscale[4]
quantizer scale calculated from quant_matrixes
Definition: mjpegdec.h:54
int size
Definition: avcodec.h:974
void av_log(void *avcl, int level, const char *fmt,...) av_printf_format(3
Send the specified message to the log if the level is less than or equal to the current av_log_level...
int ff_mjpeg_decode_dht(MJpegDecodeContext *s)
Definition: mjpegdec.c:167
AVCodec.
Definition: avcodec.h:2796
MJPEG encoder and decoder.
static int decode(MimicContext *ctx, int quality, int num_coeffs, int is_iframe)
Definition: mimic.c:275
uint8_t
#define MKBETAG(a, b, c, d)
Definition: common.h:239
AVCodec ff_mjpegb_decoder
Definition: mjpegbdec.c:154
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:188
const char * name
Name of the codec implementation.
Definition: avcodec.h:2803
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:684
AVFrame * picture_ptr
Definition: mjpegdec.h:90
const char data[16]
Definition: mxf.c:70
Definition: mjpeg.h:78
Definition: mjpeg.h:44
av_cold int ff_mjpeg_decode_end(AVCodecContext *avctx)
Definition: mjpegdec.c:1666
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:150
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:144
Definition: mjpeg.h:61
Libavcodec external API header.
int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
Definition: mjpegdec.c:221
int err_recognition
Error recognition; may misdetect some more or less valid parts as errors.
Definition: avcodec.h:2406
Definition: mjpeg.h:77
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:254
GetBitContext gb
Definition: mjpegdec.h:46
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:544
static int mjpegb_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: mjpegbdec.c:42
NULL
Definition: eval.c:55
int debug
debug
Definition: avcodec.h:2362
main external API structure.
Definition: avcodec.h:1050
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:490
#define AV_EF_EXPLODE
Definition: avcodec.h:2417
#define FF_DEBUG_QP
Definition: avcodec.h:2367
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:263
uint8_t * data
Definition: avcodec.h:973
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:375
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:304
void * priv_data
Definition: avcodec.h:1092
av_cold int ff_mjpeg_decode_init(AVCodecContext *avctx)
Definition: mjpegdec.c:85
int ff_mjpeg_decode_sos(MJpegDecodeContext *s, const uint8_t *mb_bitmask, const AVFrame *reference)
Definition: mjpegdec.c:1016
static av_cold int init(AVCodecParserContext *s)
Definition: h264_parser.c:499
MJPEG decoder.
static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg)
Definition: mjpegbdec.c:33
This structure stores compressed data.
Definition: avcodec.h:950
#define FFMIN(a, b)
Definition: common.h:57