lavc decoders: work with refcounted frames.
[libav.git] / libavcodec / escape124.c
1 /*
2 * Escape 124 Video Decoder
3 * Copyright (C) 2008 Eli Friedman (eli.friedman@gmail.com)
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
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;
41 MacroBlock* blocks;
42 } CodeBook;
43
44 typedef struct Escape124Context {
45 AVFrame frame;
46
47 unsigned num_superblocks;
48
49 CodeBook codebooks[3];
50 } Escape124Context;
51
52 static int can_safely_read(GetBitContext* gb, int bits) {
53 return get_bits_left(gb) >= bits;
54 }
55
56 /**
57 * Initialize the decoder
58 * @param avctx decoder context
59 * @return 0 success, negative on error
60 */
61 static av_cold int escape124_decode_init(AVCodecContext *avctx)
62 {
63 Escape124Context *s = avctx->priv_data;
64
65 avctx->pix_fmt = AV_PIX_FMT_RGB555;
66
67 s->num_superblocks = ((unsigned)avctx->width / 8) *
68 ((unsigned)avctx->height / 8);
69
70 return 0;
71 }
72
73 static av_cold int escape124_decode_close(AVCodecContext *avctx)
74 {
75 unsigned i;
76 Escape124Context *s = avctx->priv_data;
77
78 for (i = 0; i < 3; i++)
79 av_free(s->codebooks[i].blocks);
80
81 av_frame_unref(&s->frame);
82
83 return 0;
84 }
85
86 static CodeBook unpack_codebook(GetBitContext* gb, unsigned depth,
87 unsigned size)
88 {
89 unsigned i, j;
90 CodeBook cb = { 0 };
91
92 if (!can_safely_read(gb, size * 34))
93 return cb;
94
95 if (size >= INT_MAX / sizeof(MacroBlock))
96 return cb;
97 cb.blocks = av_malloc(size ? size * sizeof(MacroBlock) : 1);
98 if (!cb.blocks)
99 return cb;
100
101 cb.depth = depth;
102 cb.size = size;
103 for (i = 0; i < size; i++) {
104 unsigned mask_bits = get_bits(gb, 4);
105 unsigned color0 = get_bits(gb, 15);
106 unsigned color1 = get_bits(gb, 15);
107
108 for (j = 0; j < 4; j++) {
109 if (mask_bits & (1 << j))
110 cb.blocks[i].pixels[j] = color1;
111 else
112 cb.blocks[i].pixels[j] = color0;
113 }
114 }
115 return cb;
116 }
117
118 static unsigned decode_skip_count(GetBitContext* gb)
119 {
120 unsigned value;
121 // This function reads a maximum of 23 bits,
122 // which is within the padding space
123 if (!can_safely_read(gb, 1))
124 return -1;
125 value = get_bits1(gb);
126 if (!value)
127 return value;
128
129 value += get_bits(gb, 3);
130 if (value != (1 + ((1 << 3) - 1)))
131 return value;
132
133 value += get_bits(gb, 7);
134 if (value != (1 + ((1 << 3) - 1)) + ((1 << 7) - 1))
135 return value;
136
137 return value + get_bits(gb, 12);
138 }
139
140 static MacroBlock decode_macroblock(Escape124Context* s, GetBitContext* gb,
141 int* codebook_index, int superblock_index)
142 {
143 // This function reads a maximum of 22 bits; the callers
144 // guard this function appropriately
145 unsigned block_index, depth;
146
147 if (get_bits1(gb)) {
148 static const char transitions[3][2] = { {2, 1}, {0, 2}, {1, 0} };
149 *codebook_index = transitions[*codebook_index][get_bits1(gb)];
150 }
151
152 depth = s->codebooks[*codebook_index].depth;
153
154 // depth = 0 means that this shouldn't read any bits;
155 // in theory, this is the same as get_bits(gb, 0), but
156 // that doesn't actually work.
157 block_index = depth ? get_bits(gb, depth) : 0;
158
159 if (*codebook_index == 1) {
160 block_index += superblock_index << s->codebooks[1].depth;
161 }
162
163 // This condition can occur with invalid bitstreams and
164 // *codebook_index == 2
165 if (block_index >= s->codebooks[*codebook_index].size)
166 return (MacroBlock) { { 0 } };
167
168 return s->codebooks[*codebook_index].blocks[block_index];
169 }
170
171 static void insert_mb_into_sb(SuperBlock* sb, MacroBlock mb, unsigned index) {
172 // Formula: ((index / 4) * 16 + (index % 4) * 2) / 2
173 uint32_t *dst = sb->pixels32 + index + (index & -4);
174
175 // This technically violates C99 aliasing rules, but it should be safe.
176 dst[0] = mb.pixels32[0];
177 dst[4] = mb.pixels32[1];
178 }
179
180 static void copy_superblock(uint16_t* dest, unsigned dest_stride,
181 uint16_t* src, unsigned src_stride)
182 {
183 unsigned y;
184 if (src)
185 for (y = 0; y < 8; y++)
186 memcpy(dest + y * dest_stride, src + y * src_stride,
187 sizeof(uint16_t) * 8);
188 else
189 for (y = 0; y < 8; y++)
190 memset(dest + y * dest_stride, 0, sizeof(uint16_t) * 8);
191 }
192
193 static const uint16_t mask_matrix[] = {0x1, 0x2, 0x10, 0x20,
194 0x4, 0x8, 0x40, 0x80,
195 0x100, 0x200, 0x1000, 0x2000,
196 0x400, 0x800, 0x4000, 0x8000};
197
198 static int escape124_decode_frame(AVCodecContext *avctx,
199 void *data, int *got_frame,
200 AVPacket *avpkt)
201 {
202 const uint8_t *buf = avpkt->data;
203 int buf_size = avpkt->size;
204 Escape124Context *s = avctx->priv_data;
205 AVFrame *frame = data;
206
207 GetBitContext gb;
208 unsigned frame_flags, frame_size;
209 unsigned i;
210
211 unsigned superblock_index, cb_index = 1,
212 superblock_col_index = 0,
213 superblocks_per_row = avctx->width / 8, skip = -1;
214
215 uint16_t* old_frame_data, *new_frame_data;
216 unsigned old_stride, new_stride;
217 int ret;
218
219 init_get_bits(&gb, buf, buf_size * 8);
220
221 // This call also guards the potential depth reads for the
222 // codebook unpacking.
223 if (!can_safely_read(&gb, 64))
224 return -1;
225
226 frame_flags = get_bits_long(&gb, 32);
227 frame_size = get_bits_long(&gb, 32);
228
229 // Leave last frame unchanged
230 // FIXME: Is this necessary? I haven't seen it in any real samples
231 if (!(frame_flags & 0x114) || !(frame_flags & 0x7800000)) {
232 if (!s->frame.data[0])
233 return AVERROR_INVALIDDATA;
234
235 av_log(NULL, AV_LOG_DEBUG, "Skipping frame\n");
236
237 *got_frame = 1;
238 if ((ret = av_frame_ref(frame, &s->frame)) < 0)
239 return ret;
240
241 return frame_size;
242 }
243
244 for (i = 0; i < 3; i++) {
245 if (frame_flags & (1 << (17 + i))) {
246 unsigned cb_depth, cb_size;
247 if (i == 2) {
248 // This codebook can be cut off at places other than
249 // powers of 2, leaving some of the entries undefined.
250 cb_size = get_bits_long(&gb, 20);
251 cb_depth = av_log2(cb_size - 1) + 1;
252 } else {
253 cb_depth = get_bits(&gb, 4);
254 if (i == 0) {
255 // This is the most basic codebook: pow(2,depth) entries
256 // for a depth-length key
257 cb_size = 1 << cb_depth;
258 } else {
259 // This codebook varies per superblock
260 // FIXME: I don't think this handles integer overflow
261 // properly
262 cb_size = s->num_superblocks << cb_depth;
263 }
264 }
265 av_free(s->codebooks[i].blocks);
266 s->codebooks[i] = unpack_codebook(&gb, cb_depth, cb_size);
267 if (!s->codebooks[i].blocks)
268 return -1;
269 }
270 }
271
272 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) {
273 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
274 return ret;
275 }
276
277 new_frame_data = (uint16_t*)frame->data[0];
278 new_stride = frame->linesize[0] / 2;
279 old_frame_data = (uint16_t*)s->frame.data[0];
280 old_stride = s->frame.linesize[0] / 2;
281
282 for (superblock_index = 0; superblock_index < s->num_superblocks;
283 superblock_index++) {
284 MacroBlock mb;
285 SuperBlock sb;
286 unsigned multi_mask = 0;
287
288 if (skip == -1) {
289 // Note that this call will make us skip the rest of the blocks
290 // if the frame prematurely ends
291 skip = decode_skip_count(&gb);
292 }
293
294 if (skip) {
295 copy_superblock(new_frame_data, new_stride,
296 old_frame_data, old_stride);
297 } else {
298 copy_superblock(sb.pixels, 8,
299 old_frame_data, old_stride);
300
301 while (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
302 unsigned mask;
303 mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
304 mask = get_bits(&gb, 16);
305 multi_mask |= mask;
306 for (i = 0; i < 16; i++) {
307 if (mask & mask_matrix[i]) {
308 insert_mb_into_sb(&sb, mb, i);
309 }
310 }
311 }
312
313 if (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
314 unsigned inv_mask = get_bits(&gb, 4);
315 for (i = 0; i < 4; i++) {
316 if (inv_mask & (1 << i)) {
317 multi_mask ^= 0xF << i*4;
318 } else {
319 multi_mask ^= get_bits(&gb, 4) << i*4;
320 }
321 }
322
323 for (i = 0; i < 16; i++) {
324 if (multi_mask & mask_matrix[i]) {
325 if (!can_safely_read(&gb, 1))
326 break;
327 mb = decode_macroblock(s, &gb, &cb_index,
328 superblock_index);
329 insert_mb_into_sb(&sb, mb, i);
330 }
331 }
332 } else if (frame_flags & (1 << 16)) {
333 while (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
334 mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
335 insert_mb_into_sb(&sb, mb, get_bits(&gb, 4));
336 }
337 }
338
339 copy_superblock(new_frame_data, new_stride, sb.pixels, 8);
340 }
341
342 superblock_col_index++;
343 new_frame_data += 8;
344 if (old_frame_data)
345 old_frame_data += 8;
346 if (superblock_col_index == superblocks_per_row) {
347 new_frame_data += new_stride * 8 - superblocks_per_row * 8;
348 if (old_frame_data)
349 old_frame_data += old_stride * 8 - superblocks_per_row * 8;
350 superblock_col_index = 0;
351 }
352 skip--;
353 }
354
355 av_log(NULL, AV_LOG_DEBUG,
356 "Escape sizes: %i, %i, %i\n",
357 frame_size, buf_size, get_bits_count(&gb) / 8);
358
359 av_frame_unref(&s->frame);
360 if ((ret = av_frame_ref(&s->frame, frame)) < 0)
361 return ret;
362
363 *got_frame = 1;
364
365 return frame_size;
366 }
367
368
369 AVCodec ff_escape124_decoder = {
370 .name = "escape124",
371 .type = AVMEDIA_TYPE_VIDEO,
372 .id = AV_CODEC_ID_ESCAPE124,
373 .priv_data_size = sizeof(Escape124Context),
374 .init = escape124_decode_init,
375 .close = escape124_decode_close,
376 .decode = escape124_decode_frame,
377 .capabilities = CODEC_CAP_DR1,
378 .long_name = NULL_IF_CONFIG_SMALL("Escape 124"),
379 };