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path: root/libavcodec/xxan.c (plain)
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1/*
2 * Wing Commander/Xan Video Decoder
3 * Copyright (C) 2011 Konstantin Shishkov
4 * based on work by Mike Melanson
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include "libavutil/intreadwrite.h"
24#include "libavutil/mem.h"
25
26#include "avcodec.h"
27#include "bytestream.h"
28#include "internal.h"
29
30typedef struct XanContext {
31 AVCodecContext *avctx;
32 AVFrame *pic;
33
34 uint8_t *y_buffer;
35 uint8_t *scratch_buffer;
36 int buffer_size;
37 GetByteContext gb;
38} XanContext;
39
40static av_cold int xan_decode_end(AVCodecContext *avctx)
41{
42 XanContext *s = avctx->priv_data;
43
44 av_frame_free(&s->pic);
45
46 av_freep(&s->y_buffer);
47 av_freep(&s->scratch_buffer);
48
49 return 0;
50}
51
52static av_cold int xan_decode_init(AVCodecContext *avctx)
53{
54 XanContext *s = avctx->priv_data;
55
56 s->avctx = avctx;
57
58 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
59
60 if (avctx->height < 8) {
61 av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);
62 return AVERROR(EINVAL);
63 }
64 if (avctx->width & 1) {
65 av_log(avctx, AV_LOG_ERROR, "Invalid frame width: %d.\n", avctx->width);
66 return AVERROR(EINVAL);
67 }
68
69 s->buffer_size = avctx->width * avctx->height;
70 s->y_buffer = av_malloc(s->buffer_size);
71 if (!s->y_buffer)
72 return AVERROR(ENOMEM);
73 s->scratch_buffer = av_malloc(s->buffer_size + 130);
74 if (!s->scratch_buffer) {
75 xan_decode_end(avctx);
76 return AVERROR(ENOMEM);
77 }
78
79 s->pic = av_frame_alloc();
80 if (!s->pic) {
81 xan_decode_end(avctx);
82 return AVERROR(ENOMEM);
83 }
84
85 return 0;
86}
87
88static int xan_unpack_luma(XanContext *s,
89 uint8_t *dst, const int dst_size)
90{
91 int tree_size, eof;
92 int bits, mask;
93 int tree_root, node;
94 const uint8_t *dst_end = dst + dst_size;
95 GetByteContext tree = s->gb;
96 int start_off = bytestream2_tell(&tree);
97
98 tree_size = bytestream2_get_byte(&s->gb);
99 eof = bytestream2_get_byte(&s->gb);
100 tree_root = eof + tree_size;
101 bytestream2_skip(&s->gb, tree_size * 2);
102
103 node = tree_root;
104 bits = bytestream2_get_byte(&s->gb);
105 mask = 0x80;
106 for (;;) {
107 int bit = !!(bits & mask);
108 mask >>= 1;
109 bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
110 node = bytestream2_get_byte(&tree);
111 if (node == eof)
112 break;
113 if (node < eof) {
114 *dst++ = node;
115 if (dst > dst_end)
116 break;
117 node = tree_root;
118 }
119 if (!mask) {
120 if (bytestream2_get_bytes_left(&s->gb) <= 0)
121 break;
122 bits = bytestream2_get_byteu(&s->gb);
123 mask = 0x80;
124 }
125 }
126 return dst != dst_end ? AVERROR_INVALIDDATA : 0;
127}
128
129/* almost the same as in xan_wc3 decoder */
130static int xan_unpack(XanContext *s,
131 uint8_t *dest, const int dest_len)
132{
133 uint8_t opcode;
134 int size;
135 uint8_t *orig_dest = dest;
136 const uint8_t *dest_end = dest + dest_len;
137
138 while (dest < dest_end) {
139 if (bytestream2_get_bytes_left(&s->gb) <= 0)
140 return AVERROR_INVALIDDATA;
141
142 opcode = bytestream2_get_byteu(&s->gb);
143
144 if (opcode < 0xe0) {
145 int size2, back;
146 if ((opcode & 0x80) == 0) {
147 size = opcode & 3;
148 back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
149 size2 = ((opcode & 0x1c) >> 2) + 3;
150 } else if ((opcode & 0x40) == 0) {
151 size = bytestream2_peek_byte(&s->gb) >> 6;
152 back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
153 size2 = (opcode & 0x3f) + 4;
154 } else {
155 size = opcode & 3;
156 back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
157 size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
158 if (size + size2 > dest_end - dest)
159 break;
160 }
161 if (dest + size + size2 > dest_end ||
162 dest - orig_dest + size < back)
163 return AVERROR_INVALIDDATA;
164 bytestream2_get_buffer(&s->gb, dest, size);
165 dest += size;
166 av_memcpy_backptr(dest, back, size2);
167 dest += size2;
168 } else {
169 int finish = opcode >= 0xfc;
170
171 size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
172 if (dest_end - dest < size)
173 return AVERROR_INVALIDDATA;
174 bytestream2_get_buffer(&s->gb, dest, size);
175 dest += size;
176 if (finish)
177 break;
178 }
179 }
180 return dest - orig_dest;
181}
182
183static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
184{
185 XanContext *s = avctx->priv_data;
186 uint8_t *U, *V;
187 int val, uval, vval;
188 int i, j;
189 const uint8_t *src, *src_end;
190 const uint8_t *table;
191 int mode, offset, dec_size, table_size;
192
193 if (!chroma_off)
194 return 0;
195 if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
196 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
197 return AVERROR_INVALIDDATA;
198 }
199 bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
200 mode = bytestream2_get_le16(&s->gb);
201 table = s->gb.buffer;
202 table_size = bytestream2_get_le16(&s->gb);
203 offset = table_size * 2;
204 table_size += 1;
205
206 if (offset >= bytestream2_get_bytes_left(&s->gb)) {
207 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
208 return AVERROR_INVALIDDATA;
209 }
210
211 bytestream2_skip(&s->gb, offset);
212 memset(s->scratch_buffer, 0, s->buffer_size);
213 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
214 if (dec_size < 0) {
215 av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
216 return dec_size;
217 }
218
219 U = s->pic->data[1];
220 V = s->pic->data[2];
221 src = s->scratch_buffer;
222 src_end = src + dec_size;
223 if (mode) {
224 for (j = 0; j < avctx->height >> 1; j++) {
225 for (i = 0; i < avctx->width >> 1; i++) {
226 if (src_end - src < 1)
227 return 0;
228 val = *src++;
229 if (val) {
230 if (val >= table_size)
231 return AVERROR_INVALIDDATA;
232 val = AV_RL16(table + (val << 1));
233 uval = (val >> 3) & 0xF8;
234 vval = (val >> 8) & 0xF8;
235 U[i] = uval | (uval >> 5);
236 V[i] = vval | (vval >> 5);
237 }
238 }
239 U += s->pic->linesize[1];
240 V += s->pic->linesize[2];
241 }
242 if (avctx->height & 1) {
243 memcpy(U, U - s->pic->linesize[1], avctx->width >> 1);
244 memcpy(V, V - s->pic->linesize[2], avctx->width >> 1);
245 }
246 } else {
247 uint8_t *U2 = U + s->pic->linesize[1];
248 uint8_t *V2 = V + s->pic->linesize[2];
249
250 for (j = 0; j < avctx->height >> 2; j++) {
251 for (i = 0; i < avctx->width >> 1; i += 2) {
252 if (src_end - src < 1)
253 return 0;
254 val = *src++;
255 if (val) {
256 if (val >= table_size)
257 return AVERROR_INVALIDDATA;
258 val = AV_RL16(table + (val << 1));
259 uval = (val >> 3) & 0xF8;
260 vval = (val >> 8) & 0xF8;
261 U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
262 V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
263 }
264 }
265 U += s->pic->linesize[1] * 2;
266 V += s->pic->linesize[2] * 2;
267 U2 += s->pic->linesize[1] * 2;
268 V2 += s->pic->linesize[2] * 2;
269 }
270 if (avctx->height & 3) {
271 int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;
272
273 memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]);
274 memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]);
275 }
276 }
277
278 return 0;
279}
280
281static int xan_decode_frame_type0(AVCodecContext *avctx)
282{
283 XanContext *s = avctx->priv_data;
284 uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
285 unsigned chroma_off, corr_off;
286 int cur, last;
287 int i, j;
288 int ret;
289
290 chroma_off = bytestream2_get_le32(&s->gb);
291 corr_off = bytestream2_get_le32(&s->gb);
292
293 if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
294 return ret;
295
296 if (corr_off >= bytestream2_size(&s->gb)) {
297 av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
298 corr_off = 0;
299 }
300 bytestream2_seek(&s->gb, 12, SEEK_SET);
301 ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
302 if (ret) {
303 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
304 return ret;
305 }
306
307 ybuf = s->y_buffer;
308 last = *src++;
309 ybuf[0] = last << 1;
310 for (j = 1; j < avctx->width - 1; j += 2) {
311 cur = (last + *src++) & 0x1F;
312 ybuf[j] = last + cur;
313 ybuf[j+1] = cur << 1;
314 last = cur;
315 }
316 ybuf[j] = last << 1;
317 prev_buf = ybuf;
318 ybuf += avctx->width;
319
320 for (i = 1; i < avctx->height; i++) {
321 last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
322 ybuf[0] = last << 1;
323 for (j = 1; j < avctx->width - 1; j += 2) {
324 cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
325 ybuf[j] = last + cur;
326 ybuf[j+1] = cur << 1;
327 last = cur;
328 }
329 ybuf[j] = last << 1;
330 prev_buf = ybuf;
331 ybuf += avctx->width;
332 }
333
334 if (corr_off) {
335 int dec_size;
336
337 bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
338 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
339 if (dec_size < 0)
340 dec_size = 0;
341 else
342 dec_size = FFMIN(dec_size, s->buffer_size/2 - 1);
343
344 for (i = 0; i < dec_size; i++)
345 s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
346 }
347
348 src = s->y_buffer;
349 ybuf = s->pic->data[0];
350 for (j = 0; j < avctx->height; j++) {
351 for (i = 0; i < avctx->width; i++)
352 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
353 src += avctx->width;
354 ybuf += s->pic->linesize[0];
355 }
356
357 return 0;
358}
359
360static int xan_decode_frame_type1(AVCodecContext *avctx)
361{
362 XanContext *s = avctx->priv_data;
363 uint8_t *ybuf, *src = s->scratch_buffer;
364 int cur, last;
365 int i, j;
366 int ret;
367
368 if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
369 return ret;
370
371 bytestream2_seek(&s->gb, 16, SEEK_SET);
372 ret = xan_unpack_luma(s, src,
373 s->buffer_size >> 1);
374 if (ret) {
375 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
376 return ret;
377 }
378
379 ybuf = s->y_buffer;
380 for (i = 0; i < avctx->height; i++) {
381 last = (ybuf[0] + (*src++ << 1)) & 0x3F;
382 ybuf[0] = last;
383 for (j = 1; j < avctx->width - 1; j += 2) {
384 cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
385 ybuf[j] = (last + cur) >> 1;
386 ybuf[j+1] = cur;
387 last = cur;
388 }
389 ybuf[j] = last;
390 ybuf += avctx->width;
391 }
392
393 src = s->y_buffer;
394 ybuf = s->pic->data[0];
395 for (j = 0; j < avctx->height; j++) {
396 for (i = 0; i < avctx->width; i++)
397 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
398 src += avctx->width;
399 ybuf += s->pic->linesize[0];
400 }
401
402 return 0;
403}
404
405static int xan_decode_frame(AVCodecContext *avctx,
406 void *data, int *got_frame,
407 AVPacket *avpkt)
408{
409 XanContext *s = avctx->priv_data;
410 int ftype;
411 int ret;
412
413 if ((ret = ff_reget_buffer(avctx, s->pic)) < 0)
414 return ret;
415
416 bytestream2_init(&s->gb, avpkt->data, avpkt->size);
417 ftype = bytestream2_get_le32(&s->gb);
418 switch (ftype) {
419 case 0:
420 ret = xan_decode_frame_type0(avctx);
421 break;
422 case 1:
423 ret = xan_decode_frame_type1(avctx);
424 break;
425 default:
426 av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
427 return AVERROR_INVALIDDATA;
428 }
429 if (ret)
430 return ret;
431
432 if ((ret = av_frame_ref(data, s->pic)) < 0)
433 return ret;
434
435 *got_frame = 1;
436
437 return avpkt->size;
438}
439
440AVCodec ff_xan_wc4_decoder = {
441 .name = "xan_wc4",
442 .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
443 .type = AVMEDIA_TYPE_VIDEO,
444 .id = AV_CODEC_ID_XAN_WC4,
445 .priv_data_size = sizeof(XanContext),
446 .init = xan_decode_init,
447 .close = xan_decode_end,
448 .decode = xan_decode_frame,
449 .capabilities = AV_CODEC_CAP_DR1,
450};
451
generated by cgit at 2024-05-17 18:36:15 (GMT)