FFmpeg  2.1.1
escape124.c
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1 /*
2  * Escape 124 Video Decoder
3  * Copyright (C) 2008 Eli Friedman (eli.friedman@gmail.com)
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 #include "avcodec.h"
23 #include "internal.h"
24 
25 #define BITSTREAM_READER_LE
26 #include "get_bits.h"
27 
28 typedef union MacroBlock {
29  uint16_t pixels[4];
30  uint32_t pixels32[2];
31 } MacroBlock;
32 
33 typedef union SuperBlock {
34  uint16_t pixels[64];
35  uint32_t pixels32[32];
36 } SuperBlock;
37 
38 typedef struct CodeBook {
39  unsigned depth;
40  unsigned size;
42 } CodeBook;
43 
44 typedef struct Escape124Context {
46 
47  unsigned num_superblocks;
48 
51 
52 /**
53  * Initialize the decoder
54  * @param avctx decoder context
55  * @return 0 success, negative on error
56  */
58 {
59  Escape124Context *s = avctx->priv_data;
60 
62  avctx->pix_fmt = AV_PIX_FMT_RGB555;
63 
64  s->num_superblocks = ((unsigned)avctx->width / 8) *
65  ((unsigned)avctx->height / 8);
66 
67  return 0;
68 }
69 
71 {
72  unsigned i;
73  Escape124Context *s = avctx->priv_data;
74 
75  for (i = 0; i < 3; i++)
76  av_free(s->codebooks[i].blocks);
77 
78  av_frame_unref(&s->frame);
79 
80  return 0;
81 }
82 
84  unsigned size)
85 {
86  unsigned i, j;
87  CodeBook cb = { 0 };
88 
89  if (size >= INT_MAX / 34 || get_bits_left(gb) < size * 34)
90  return cb;
91 
92  if (size >= INT_MAX / sizeof(MacroBlock))
93  return cb;
94  cb.blocks = av_malloc(size ? size * sizeof(MacroBlock) : 1);
95  if (!cb.blocks)
96  return cb;
97 
98  cb.depth = depth;
99  cb.size = size;
100  for (i = 0; i < size; i++) {
101  unsigned mask_bits = get_bits(gb, 4);
102  unsigned color0 = get_bits(gb, 15);
103  unsigned color1 = get_bits(gb, 15);
104 
105  for (j = 0; j < 4; j++) {
106  if (mask_bits & (1 << j))
107  cb.blocks[i].pixels[j] = color1;
108  else
109  cb.blocks[i].pixels[j] = color0;
110  }
111  }
112  return cb;
113 }
114 
115 static unsigned decode_skip_count(GetBitContext* gb)
116 {
117  unsigned value;
118  // This function reads a maximum of 23 bits,
119  // which is within the padding space
120  if (get_bits_left(gb) < 1)
121  return -1;
122  value = get_bits1(gb);
123  if (!value)
124  return value;
125 
126  value += get_bits(gb, 3);
127  if (value != (1 + ((1 << 3) - 1)))
128  return value;
129 
130  value += get_bits(gb, 7);
131  if (value != (1 + ((1 << 3) - 1)) + ((1 << 7) - 1))
132  return value;
133 
134  return value + get_bits(gb, 12);
135 }
136 
138  int* codebook_index, int superblock_index)
139 {
140  // This function reads a maximum of 22 bits; the callers
141  // guard this function appropriately
142  unsigned block_index, depth;
143 
144  if (get_bits1(gb)) {
145  static const char transitions[3][2] = { {2, 1}, {0, 2}, {1, 0} };
146  *codebook_index = transitions[*codebook_index][get_bits1(gb)];
147  }
148 
149  depth = s->codebooks[*codebook_index].depth;
150 
151  // depth = 0 means that this shouldn't read any bits;
152  // in theory, this is the same as get_bits(gb, 0), but
153  // that doesn't actually work.
154  block_index = depth ? get_bits(gb, depth) : 0;
155 
156  if (*codebook_index == 1) {
157  block_index += superblock_index << s->codebooks[1].depth;
158  }
159 
160  // This condition can occur with invalid bitstreams and
161  // *codebook_index == 2
162  if (block_index >= s->codebooks[*codebook_index].size)
163  return (MacroBlock) { { 0 } };
164 
165  return s->codebooks[*codebook_index].blocks[block_index];
166 }
167 
168 static void insert_mb_into_sb(SuperBlock* sb, MacroBlock mb, unsigned index) {
169  // Formula: ((index / 4) * 16 + (index % 4) * 2) / 2
170  uint32_t *dst = sb->pixels32 + index + (index & -4);
171 
172  // This technically violates C99 aliasing rules, but it should be safe.
173  dst[0] = mb.pixels32[0];
174  dst[4] = mb.pixels32[1];
175 }
176 
177 static void copy_superblock(uint16_t* dest, unsigned dest_stride,
178  uint16_t* src, unsigned src_stride)
179 {
180  unsigned y;
181  if (src)
182  for (y = 0; y < 8; y++)
183  memcpy(dest + y * dest_stride, src + y * src_stride,
184  sizeof(uint16_t) * 8);
185  else
186  for (y = 0; y < 8; y++)
187  memset(dest + y * dest_stride, 0, sizeof(uint16_t) * 8);
188 }
189 
190 static const uint16_t mask_matrix[] = {0x1, 0x2, 0x10, 0x20,
191  0x4, 0x8, 0x40, 0x80,
192  0x100, 0x200, 0x1000, 0x2000,
193  0x400, 0x800, 0x4000, 0x8000};
194 
196  void *data, int *got_frame,
197  AVPacket *avpkt)
198 {
199  int buf_size = avpkt->size;
200  Escape124Context *s = avctx->priv_data;
201  AVFrame *frame = data;
202 
203  GetBitContext gb;
204  unsigned frame_flags, frame_size;
205  unsigned i;
206 
207  unsigned superblock_index, cb_index = 1,
208  superblock_col_index = 0,
209  superblocks_per_row = avctx->width / 8, skip = -1;
210 
211  uint16_t* old_frame_data, *new_frame_data;
212  unsigned old_stride, new_stride;
213 
214  int ret;
215 
216  if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)
217  return ret;
218 
219  // This call also guards the potential depth reads for the
220  // codebook unpacking.
221  if (get_bits_left(&gb) < 64)
222  return -1;
223 
224  frame_flags = get_bits_long(&gb, 32);
225  frame_size = get_bits_long(&gb, 32);
226 
227  // Leave last frame unchanged
228  // FIXME: Is this necessary? I haven't seen it in any real samples
229  if (!(frame_flags & 0x114) || !(frame_flags & 0x7800000)) {
230  if (!s->frame.data[0])
231  return AVERROR_INVALIDDATA;
232 
233  av_log(avctx, AV_LOG_DEBUG, "Skipping frame\n");
234 
235  *got_frame = 1;
236  if ((ret = av_frame_ref(frame, &s->frame)) < 0)
237  return ret;
238 
239  return frame_size;
240  }
241 
242  for (i = 0; i < 3; i++) {
243  if (frame_flags & (1 << (17 + i))) {
244  unsigned cb_depth, cb_size;
245  if (i == 2) {
246  // This codebook can be cut off at places other than
247  // powers of 2, leaving some of the entries undefined.
248  cb_size = get_bits_long(&gb, 20);
249  cb_depth = av_log2(cb_size - 1) + 1;
250  } else {
251  cb_depth = get_bits(&gb, 4);
252  if (i == 0) {
253  // This is the most basic codebook: pow(2,depth) entries
254  // for a depth-length key
255  cb_size = 1 << cb_depth;
256  } else {
257  // This codebook varies per superblock
258  // FIXME: I don't think this handles integer overflow
259  // properly
260  cb_size = s->num_superblocks << cb_depth;
261  }
262  }
263  av_free(s->codebooks[i].blocks);
264  s->codebooks[i] = unpack_codebook(&gb, cb_depth, cb_size);
265  if (!s->codebooks[i].blocks)
266  return -1;
267  }
268  }
269 
270  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
271  return ret;
272 
273  new_frame_data = (uint16_t*)frame->data[0];
274  new_stride = frame->linesize[0] / 2;
275  old_frame_data = (uint16_t*)s->frame.data[0];
276  old_stride = s->frame.linesize[0] / 2;
277 
278  for (superblock_index = 0; superblock_index < s->num_superblocks;
279  superblock_index++) {
280  MacroBlock mb;
281  SuperBlock sb;
282  unsigned multi_mask = 0;
283 
284  if (skip == -1) {
285  // Note that this call will make us skip the rest of the blocks
286  // if the frame prematurely ends
287  skip = decode_skip_count(&gb);
288  }
289 
290  if (skip) {
291  copy_superblock(new_frame_data, new_stride,
292  old_frame_data, old_stride);
293  } else {
294  copy_superblock(sb.pixels, 8,
295  old_frame_data, old_stride);
296 
297  while (get_bits_left(&gb) >= 1 && !get_bits1(&gb)) {
298  unsigned mask;
299  mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
300  mask = get_bits(&gb, 16);
301  multi_mask |= mask;
302  for (i = 0; i < 16; i++) {
303  if (mask & mask_matrix[i]) {
304  insert_mb_into_sb(&sb, mb, i);
305  }
306  }
307  }
308 
309  if (!get_bits1(&gb)) {
310  unsigned inv_mask = get_bits(&gb, 4);
311  for (i = 0; i < 4; i++) {
312  if (inv_mask & (1 << i)) {
313  multi_mask ^= 0xF << i*4;
314  } else {
315  multi_mask ^= get_bits(&gb, 4) << i*4;
316  }
317  }
318 
319  for (i = 0; i < 16; i++) {
320  if (multi_mask & mask_matrix[i]) {
321  mb = decode_macroblock(s, &gb, &cb_index,
322  superblock_index);
323  insert_mb_into_sb(&sb, mb, i);
324  }
325  }
326  } else if (frame_flags & (1 << 16)) {
327  while (get_bits_left(&gb) >= 1 && !get_bits1(&gb)) {
328  mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
329  insert_mb_into_sb(&sb, mb, get_bits(&gb, 4));
330  }
331  }
332 
333  copy_superblock(new_frame_data, new_stride, sb.pixels, 8);
334  }
335 
336  superblock_col_index++;
337  new_frame_data += 8;
338  if (old_frame_data)
339  old_frame_data += 8;
340  if (superblock_col_index == superblocks_per_row) {
341  new_frame_data += new_stride * 8 - superblocks_per_row * 8;
342  if (old_frame_data)
343  old_frame_data += old_stride * 8 - superblocks_per_row * 8;
344  superblock_col_index = 0;
345  }
346  skip--;
347  }
348 
349  av_log(avctx, AV_LOG_DEBUG,
350  "Escape sizes: %i, %i, %i\n",
351  frame_size, buf_size, get_bits_count(&gb) / 8);
352 
353  av_frame_unref(&s->frame);
354  if ((ret = av_frame_ref(&s->frame, frame)) < 0)
355  return ret;
356 
357  *got_frame = 1;
358 
359  return frame_size;
360 }
361 
362 
364  .name = "escape124",
365  .long_name = NULL_IF_CONFIG_SMALL("Escape 124"),
366  .type = AVMEDIA_TYPE_VIDEO,
367  .id = AV_CODEC_ID_ESCAPE124,
368  .priv_data_size = sizeof(Escape124Context),
372  .capabilities = CODEC_CAP_DR1,
373 };
static const uint16_t mask_matrix[]
Definition: escape124.c:190
const char * s
Definition: avisynth_c.h:668
int size
This structure describes decoded (raw) audio or video data.
Definition: frame.h:96
AVFrame frame
Definition: escape124.c:45
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:255
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1064
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...
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1342
unsigned size
Definition: escape124.c:40
AVCodec.
Definition: avcodec.h:2922
#define av_cold
Definition: avcodec.h:653
static void insert_mb_into_sb(SuperBlock *sb, MacroBlock mb, unsigned index)
Definition: escape124.c:168
static double cb(void *priv, double x, double y)
Definition: vf_geq.c:96
#define AV_PIX_FMT_RGB555
Definition: avcodec.h:4938
#define mb
static unsigned decode_skip_count(GetBitContext *gb)
Definition: escape124.c:115
const char * name
Name of the codec implementation.
Definition: avcodec.h:2929
int av_frame_ref(AVFrame *dst, AVFrame *src)
Setup a new reference to the data described by a given frame.
Definition: frame.c:247
static void copy_superblock(uint16_t *dest, unsigned dest_stride, uint16_t *src, unsigned src_stride)
Definition: escape124.c:177
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:742
const char data[16]
Definition: mxf.c:68
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:207
uint32_t pixels32[2]
Definition: escape124.c:30
bitstream reader API header.
uint16_t pixels[4]
Definition: escape124.c:29
static AVFrame * frame
Definition: demuxing.c:51
static const uint8_t frame_size[4]
Definition: g723_1_data.h:58
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:583
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:219
static const uint16_t mask[17]
Definition: lzw.c:37
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:151
CodeBook codebooks[3]
Definition: escape124.c:49
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: avcodec.h:4168
Libavcodec external API header.
int depth
Definition: v4l.c:61
static av_cold int escape124_decode_close(AVCodecContext *avctx)
Definition: escape124.c:70
void av_frame_unref(AVFrame *frame)
Unreference all the buffers referenced by frame and reset the frame fields.
Definition: frame.c:351
float y
ret
Definition: avfilter.c:961
int width
picture width / height.
Definition: avcodec.h:1314
void * av_malloc(size_t size) av_malloc_attrib 1(1)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:73
AVCodec ff_escape124_decoder
Definition: escape124.c:363
MacroBlock * blocks
Definition: escape124.c:41
uint16_t pixels[64]
Definition: escape124.c:34
AVS_Value src
Definition: avisynth_c.h:523
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:436
main external API structure.
Definition: avcodec.h:1146
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:538
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:941
unsigned depth
Definition: escape124.c:39
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:299
double value
Definition: eval.c:83
void avcodec_get_frame_defaults(AVFrame *frame)
Set the fields of the given AVFrame to default values.
Definition: utils.c:1046
static CodeBook unpack_codebook(GetBitContext *gb, unsigned depth, unsigned size)
Definition: escape124.c:83
int index
Definition: gxfenc.c:89
uint8_t * data
Definition: avcodec.h:1063
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:124
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:332
unsigned num_superblocks
Definition: escape124.c:47
void * priv_data
Definition: avcodec.h:1182
common internal api header.
#define AVERROR_INVALIDDATA
#define av_log2
Definition: intmath.h:89
uint32_t pixels32[32]
Definition: escape124.c:35
static av_cold int escape124_decode_init(AVCodecContext *avctx)
Initialize the decoder.
Definition: escape124.c:57
static int decode(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: crystalhd.c:868
This structure stores compressed data.
Definition: avcodec.h:1040
#define AV_GET_BUFFER_FLAG_REF
The decoder will keep a reference to the frame and may reuse it later.
Definition: avcodec.h:910
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:107
static MacroBlock decode_macroblock(Escape124Context *s, GetBitContext *gb, int *codebook_index, int superblock_index)
Definition: escape124.c:137
static int escape124_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: escape124.c:195