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 
61  /* reset on every SOI */
62  s->restart_interval = 0;
63  s->restart_count = 0;
64  s->mjpb_skiptosod = 0;
65 
66  if (buf_end - buf_ptr >= 1 << 28)
67  return AVERROR_INVALIDDATA;
68 
69  init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8);
70 
71  skip_bits(&hgb, 32); /* reserved zeros */
72 
73  if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g')) {
74  av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n");
75  return AVERROR_INVALIDDATA;
76  }
77 
78  field_size = get_bits_long(&hgb, 32); /* field size */
79  av_log(avctx, AV_LOG_DEBUG, "field size: 0x%"PRIx32"\n", field_size);
80  skip_bits(&hgb, 32); /* padded field size */
81  second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n");
82  av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%"PRIx32"\n",
83  second_field_offs);
84 
85  dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n");
86  av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%"PRIx32"\n", dqt_offs);
87  if (dqt_offs) {
88  init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8);
89  s->start_code = DQT;
90  ret = ff_mjpeg_decode_dqt(s);
91  if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
92  return ret;
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  init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8);
99  s->start_code = DHT;
101  }
102 
103  sof_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
104  av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%"PRIx32"\n", sof_offs);
105  if (sof_offs) {
106  init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8);
107  s->start_code = SOF0;
108  if ((ret = ff_mjpeg_decode_sof(s)) < 0)
109  return ret;
110  }
111 
112  sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n");
113  av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%"PRIx32"\n", sos_offs);
114  sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
115  av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%"PRIx32"\n", sod_offs);
116  if (sos_offs) {
117  init_get_bits(&s->gb, buf_ptr + sos_offs,
118  8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs));
119  s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16));
120  s->start_code = SOS;
121  ret = ff_mjpeg_decode_sos(s, NULL, 0, NULL);
122  if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
123  return ret;
124  }
125 
126  if (s->interlaced) {
127  s->bottom_field ^= 1;
128  /* if not bottom field, do not output image yet */
129  if (s->bottom_field != s->interlace_polarity && second_field_offs) {
130  buf_ptr = buf + second_field_offs;
131  goto read_header;
132  }
133  }
134 
135  //XXX FIXME factorize, this looks very similar to the EOI code
136 
137  if(!s->got_picture) {
138  av_log(avctx, AV_LOG_WARNING, "no picture\n");
139  return buf_size;
140  }
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),
161  .close = ff_mjpeg_decode_end,
163  .capabilities = AV_CODEC_CAP_DR1,
164  .max_lowres = 3,
165  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
166 };
#define NULL
Definition: coverity.c:32
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
Definition: mjpeg.h:73
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int ff_mjpeg_decode_dqt(MJpegDecodeContext *s)
Definition: mjpegdec.c:200
int qscale[4]
quantizer scale calculated from quant_matrixes
Definition: mjpegdec.h:58
int size
Definition: avcodec.h:1478
int ff_mjpeg_decode_dht(MJpegDecodeContext *s)
Definition: mjpegdec.c:241
AVCodec.
Definition: avcodec.h:3481
MJPEG encoder and decoder.
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:42
#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:40
Definition: mjpeg.h:72
uint8_t
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:443
AVFrame * picture_ptr
Definition: mjpegdec.h:100
uint8_t * data
Definition: avcodec.h:1477
ptrdiff_t size
Definition: opengl_enc.c:100
#define av_log(a,...)
av_cold int ff_mjpeg_decode_end(AVCodecContext *avctx)
Definition: mjpegdec.c:2745
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
const char * name
Name of the codec implementation.
Definition: avcodec.h:3488
Definition: mjpeg.h:39
Definition: mjpeg.h:56
int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
Definition: mjpegdec.c:305
int err_recognition
Error recognition; may misdetect some more or less valid parts as errors.
Definition: avcodec.h:2694
#define FFMIN(a, b)
Definition: common.h:96
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:446
#define s(width, name)
Definition: cbs_vp9.c:257
#define AV_EF_EXPLODE
abort decoding on minor error detection
Definition: avcodec.h:2705
GetBitContext gb
Definition: mjpegdec.h:49
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
static int mjpegb_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: mjpegbdec.c:43
Libavcodec external API header.
int debug
debug
Definition: avcodec.h:2650
main external API structure.
Definition: avcodec.h:1565
void * buf
Definition: avisynth_c.h:766
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:659
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:546
int ff_mjpeg_decode_sos(MJpegDecodeContext *s, const uint8_t *mb_bitmask, int mb_bitmask_size, const AVFrame *reference)
Definition: mjpegdec.c:1567
av_cold int ff_mjpeg_decode_init(AVCodecContext *avctx)
Definition: mjpegdec.c:139
common internal api header.
#define FF_DEBUG_QP
Definition: avcodec.h:2655
#define MKBETAG(a, b, c, d)
Definition: common.h:367
void * priv_data
Definition: avcodec.h:1592
int got_picture
we found a SOF and picture is valid, too.
Definition: mjpegdec.h:101
MJPEG decoder.
static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg)
Definition: mjpegbdec.c:34
This structure stores compressed data.
Definition: avcodec.h:1454
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:981
#define FFMAX3(a, b, c)
Definition: common.h:95