FFmpeg: libavcodec/xxan.c Source File

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libavcodec

xxan.c

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1 /*

2 * Wing Commander/Xan Video Decoder

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 */

23 #include "avcodec.h"

24 #include "libavutil/intreadwrite.h"

25 #include "libavutil/mem.h"

26 #include "bytestream.h"

27 #define BITSTREAM_READER_LE

28 #include "get_bits.h"

29 #include "internal.h"

31 typedef struct XanContext {

32 AVCodecContext *avctx;

33 AVFrame *pic;

35 uint8_t *y_buffer;

36 uint8_t *scratch_buffer;

37 int buffer_size;

38 GetByteContext gb;

39 } XanContext;

41 static av_cold int xan_decode_end(AVCodecContext *avctx)

42 {

43 XanContext *s = avctx->priv_data;

45 av_frame_free(&s->pic);

47 av_freep(&s->y_buffer);

48 av_freep(&s->scratch_buffer);

50 return 0;

51 }

53 static av_cold int xan_decode_init(AVCodecContext *avctx)

54 {

55 XanContext *s = avctx->priv_data;

57 s->avctx = avctx;

59 avctx->pix_fmt = AV_PIX_FMT_YUV420P;

61 if (avctx->height < 8) {

62 av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);

63 return AVERROR(EINVAL);

64 }

65 if (avctx->width & 1) {

66 av_log(avctx, AV_LOG_ERROR, "Invalid frame width: %d.\n", avctx->width);

67 return AVERROR(EINVAL);

68 }

70 s->buffer_size = avctx->width * avctx->height;

71 s->y_buffer = av_malloc(s->buffer_size);

72 if (!s->y_buffer)

73 return AVERROR(ENOMEM);

74 s->scratch_buffer = av_malloc(s->buffer_size + 130);

75 if (!s->scratch_buffer) {

76 xan_decode_end(avctx);

77 return AVERROR(ENOMEM);

78 }

80 s->pic = av_frame_alloc();

81 if (!s->pic) {

82 xan_decode_end(avctx);

83 return AVERROR(ENOMEM);

84 }

86 return 0;

87 }

89 static int xan_unpack_luma(XanContext *s,

90 uint8_t *dst, const int dst_size)

91 {

92 int tree_size, eof;

93 int bits, mask;

94 int tree_root, node;

95 const uint8_t *dst_end = dst + dst_size;

96 GetByteContext tree = s->gb;

97 int start_off = bytestream2_tell(&tree);

99 tree_size = bytestream2_get_byte(&s->gb);

100 eof = bytestream2_get_byte(&s->gb);

101 tree_root = eof + tree_size;

102 bytestream2_skip(&s->gb, tree_size * 2);

103

104 node = tree_root;

105 bits = bytestream2_get_byte(&s->gb);

106 mask = 0x80;

107 for (;;) {

108 int bit = !!(bits & mask);

109 mask >>= 1;

110 bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);

111 node = bytestream2_get_byte(&tree);

112 if (node == eof)

113 break;

114 if (node < eof) {

115 *dst++ = node;

116 if (dst > dst_end)

117 break;

118 node = tree_root;

119 }

120 if (!mask) {

121 if (bytestream2_get_bytes_left(&s->gb) <= 0)

122 break;

123 bits = bytestream2_get_byteu(&s->gb);

124 mask = 0x80;

125 }

126 }

127 return dst != dst_end ? AVERROR_INVALIDDATA : 0;

128 }

129

130 /* almost the same as in xan_wc3 decoder */

131 static int xan_unpack(XanContext *s,

132 uint8_t *dest, const int dest_len)

133 {

134 uint8_t opcode;

135 int size;

136 uint8_t *orig_dest = dest;

137 const uint8_t *dest_end = dest + dest_len;

138

139 while (dest < dest_end) {

140 if (bytestream2_get_bytes_left(&s->gb) <= 0)

141 return AVERROR_INVALIDDATA;

142

143 opcode = bytestream2_get_byteu(&s->gb);

144

145 if (opcode < 0xe0) {

146 int size2, back;

147 if ((opcode & 0x80) == 0) {

148 size = opcode & 3;

149 back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;

150 size2 = ((opcode & 0x1c) >> 2) + 3;

151 } else if ((opcode & 0x40) == 0) {

152 size = bytestream2_peek_byte(&s->gb) >> 6;

153 back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;

154 size2 = (opcode & 0x3f) + 4;

155 } else {

156 size = opcode & 3;

157 back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;

158 size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;

159 if (size + size2 > dest_end - dest)

160 break;

161 }

162 if (dest + size + size2 > dest_end ||

163 dest - orig_dest + size < back)

164 return AVERROR_INVALIDDATA;

165 bytestream2_get_buffer(&s->gb, dest, size);

166 dest += size;

167 av_memcpy_backptr(dest, back, size2);

168 dest += size2;

169 } else {

170 int finish = opcode >= 0xfc;

171

172 size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;

173 if (dest_end - dest < size)

174 return AVERROR_INVALIDDATA;

175 bytestream2_get_buffer(&s->gb, dest, size);

176 dest += size;

177 if (finish)

178 break;

179 }

180 }

181 return dest - orig_dest;

182 }

183

184 static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)

185 {

186 XanContext *s = avctx->priv_data;

187 uint8_t *U, *V;

188 int val, uval, vval;

189 int i, j;

190 const uint8_t *src, *src_end;

191 const uint8_t *table;

192 int mode, offset, dec_size, table_size;

193

194 if (!chroma_off)

195 return 0;

196 if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {

197 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");

198 return AVERROR_INVALIDDATA;

199 }

200 bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);

201 mode = bytestream2_get_le16(&s->gb);

202 table = s->gb.buffer;

203 table_size = bytestream2_get_le16(&s->gb);

204 offset = table_size * 2;

205 table_size += 1;

206

207 if (offset >= bytestream2_get_bytes_left(&s->gb)) {

208 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");

209 return AVERROR_INVALIDDATA;

210 }

211

212 bytestream2_skip(&s->gb, offset);

213 memset(s->scratch_buffer, 0, s->buffer_size);

214 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);

215 if (dec_size < 0) {

216 av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");

217 return dec_size;

218 }

219

220 U = s->pic->data[1];

221 V = s->pic->data[2];

222 src = s->scratch_buffer;

223 src_end = src + dec_size;

224 if (mode) {

225 for (j = 0; j < avctx->height >> 1; j++) {

226 for (i = 0; i < avctx->width >> 1; i++) {

227 if (src_end - src < 1)

228 return 0;

229 val = *src++;

230 if (val) {

231 if (val >= table_size)

232 return AVERROR_INVALIDDATA;

233 val = AV_RL16(table + (val << 1));

234 uval = (val >> 3) & 0xF8;

235 vval = (val >> 8) & 0xF8;

236 U[i] = uval | (uval >> 5);

237 V[i] = vval | (vval >> 5);

238 }

239 }

240 U += s->pic->linesize[1];

241 V += s->pic->linesize[2];

242 }

243 if (avctx->height & 1) {

244 memcpy(U, U - s->pic->linesize[1], avctx->width >> 1);

245 memcpy(V, V - s->pic->linesize[2], avctx->width >> 1);

246 }

247 } else {

248 uint8_t *U2 = U + s->pic->linesize[1];

249 uint8_t *V2 = V + s->pic->linesize[2];

250

251 for (j = 0; j < avctx->height >> 2; j++) {

252 for (i = 0; i < avctx->width >> 1; i += 2) {

253 if (src_end - src < 1)

254 return 0;

255 val = *src++;

256 if (val) {

257 if (val >= table_size)

258 return AVERROR_INVALIDDATA;

259 val = AV_RL16(table + (val << 1));

260 uval = (val >> 3) & 0xF8;

261 vval = (val >> 8) & 0xF8;

262 U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);

263 V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);

264 }

265 }

266 U += s->pic->linesize[1] * 2;

267 V += s->pic->linesize[2] * 2;

268 U2 += s->pic->linesize[1] * 2;

269 V2 += s->pic->linesize[2] * 2;

270 }

271 if (avctx->height & 3) {

272 int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;

273

274 memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]);

275 memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]);

276 }

277 }

278

279 return 0;

280 }

281

282 static int xan_decode_frame_type0(AVCodecContext *avctx)

283 {

284 XanContext *s = avctx->priv_data;

285 uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;

286 unsigned chroma_off, corr_off;

287 int cur, last;

288 int i, j;

289 int ret;

290

291 chroma_off = bytestream2_get_le32(&s->gb);

292 corr_off = bytestream2_get_le32(&s->gb);

293

294 if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)

295 return ret;

296

297 if (corr_off >= bytestream2_size(&s->gb)) {

298 av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");

299 corr_off = 0;

300 }

301 bytestream2_seek(&s->gb, 12, SEEK_SET);

302 ret = xan_unpack_luma(s, src, s->buffer_size >> 1);

303 if (ret) {

304 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");

305 return ret;

306 }

307

308 ybuf = s->y_buffer;

309 last = *src++;

310 ybuf[0] = last << 1;

311 for (j = 1; j < avctx->width - 1; j += 2) {

312 cur = (last + *src++) & 0x1F;

313 ybuf[j] = last + cur;

314 ybuf[j+1] = cur << 1;

315 last = cur;

316 }

317 ybuf[j] = last << 1;

318 prev_buf = ybuf;

319 ybuf += avctx->width;

320

321 for (i = 1; i < avctx->height; i++) {

322 last = ((prev_buf[0] >> 1) + *src++) & 0x1F;

323 ybuf[0] = last << 1;

324 for (j = 1; j < avctx->width - 1; j += 2) {

325 cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;

326 ybuf[j] = last + cur;

327 ybuf[j+1] = cur << 1;

328 last = cur;

329 }

330 ybuf[j] = last << 1;

331 prev_buf = ybuf;

332 ybuf += avctx->width;

333 }

334

335 if (corr_off) {

336 int dec_size;

337

338 bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);

339 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);

340 if (dec_size < 0)

341 dec_size = 0;

342 else

343 dec_size = FFMIN(dec_size, s->buffer_size/2 - 1);

344

345 for (i = 0; i < dec_size; i++)

346 s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;

347 }

348

349 src = s->y_buffer;

350 ybuf = s->pic->data[0];

351 for (j = 0; j < avctx->height; j++) {

352 for (i = 0; i < avctx->width; i++)

353 ybuf[i] = (src[i] << 2) | (src[i] >> 3);

354 src += avctx->width;

355 ybuf += s->pic->linesize[0];

356 }

357

358 return 0;

359 }

360

361 static int xan_decode_frame_type1(AVCodecContext *avctx)

362 {

363 XanContext *s = avctx->priv_data;

364 uint8_t *ybuf, *src = s->scratch_buffer;

365 int cur, last;

366 int i, j;

367 int ret;

368

369 if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)

370 return ret;

371

372 bytestream2_seek(&s->gb, 16, SEEK_SET);

373 ret = xan_unpack_luma(s, src,

374 s->buffer_size >> 1);

375 if (ret) {

376 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");

377 return ret;

378 }

379

380 ybuf = s->y_buffer;

381 for (i = 0; i < avctx->height; i++) {

382 last = (ybuf[0] + (*src++ << 1)) & 0x3F;

383 ybuf[0] = last;

384 for (j = 1; j < avctx->width - 1; j += 2) {

385 cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;

386 ybuf[j] = (last + cur) >> 1;

387 ybuf[j+1] = cur;

388 last = cur;

389 }

390 ybuf[j] = last;

391 ybuf += avctx->width;

392 }

393

394 src = s->y_buffer;

395 ybuf = s->pic->data[0];

396 for (j = 0; j < avctx->height; j++) {

397 for (i = 0; i < avctx->width; i++)

398 ybuf[i] = (src[i] << 2) | (src[i] >> 3);

399 src += avctx->width;

400 ybuf += s->pic->linesize[0];

401 }

402

403 return 0;

404 }

405

406 static int xan_decode_frame(AVCodecContext *avctx,

407 void *data, int *got_frame,

408 AVPacket *avpkt)

409 {

410 XanContext *s = avctx->priv_data;

411 int ftype;

412 int ret;

413

414 if ((ret = ff_reget_buffer(avctx, s->pic)) < 0)

415 return ret;

416

417 bytestream2_init(&s->gb, avpkt->data, avpkt->size);

418 ftype = bytestream2_get_le32(&s->gb);

419 switch (ftype) {

420 case 0:

421 ret = xan_decode_frame_type0(avctx);

422 break;

423 case 1:

424 ret = xan_decode_frame_type1(avctx);

425 break;

426 default:

427 av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);

428 return AVERROR_INVALIDDATA;

429 }

430 if (ret)

431 return ret;

432

433 if ((ret = av_frame_ref(data, s->pic)) < 0)

434 return ret;

435

436 *got_frame = 1;

437

438 return avpkt->size;

439 }

440

441 AVCodec ff_xan_wc4_decoder = {

442 .name = "xan_wc4",

443 .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),

444 .type = AVMEDIA_TYPE_VIDEO,

445 .id = AV_CODEC_ID_XAN_WC4,

446 .priv_data_size = sizeof(XanContext),

447 .init = xan_decode_init,

448 .close = xan_decode_end,

449 .decode = xan_decode_frame,

450 .capabilities = CODEC_CAP_DR1,

451 };

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