FFmpeg: libavcodec/mss4.c Source File

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libavcodec

mss4.c

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1 /*

2 * Microsoft Screen 4 (aka Microsoft Expression Encoder Screen) decoder

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 */

22 /**

23 * @file

24 * Microsoft Screen 4 (aka Microsoft Titanium Screen 2,

25 * aka Microsoft Expression Encoder Screen) decoder

26 */

28 #include "avcodec.h"

29 #include "bytestream.h"

30 #include "get_bits.h"

31 #include "internal.h"

32 #include "mss34dsp.h"

33 #include "unary.h"

35 #define HEADER_SIZE 8

37 enum FrameType {

38 INTRA_FRAME = 0,

39 INTER_FRAME,

40 SKIP_FRAME

41 };

43 enum BlockType {

44 SKIP_BLOCK = 0,

45 DCT_BLOCK,

46 IMAGE_BLOCK,

47 };

49 enum CachePos {

50 LEFT = 0,

51 TOP_LEFT,

52 TOP,

53 };

55 static const uint8_t mss4_dc_vlc_lens[2][16] = {

56 { 0, 1, 5, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0 },

57 { 0, 3, 1, 1, 1, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0 }

58 };

60 static const uint8_t mss4_ac_vlc_lens[2][16] = {

61 { 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 125 },

62 { 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 119 }

63 };

65 static const uint8_t mss4_ac_vlc_syms[2][162] = {

66 { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,

67 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,

68 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1, 0x08,

69 0x23, 0x42, 0xB1, 0xC1, 0x15, 0x52, 0xD1, 0xF0,

70 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0A, 0x16,

71 0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28,

72 0x29, 0x2A, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,

73 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,

74 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,

75 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,

76 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,

77 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,

78 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,

79 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7,

80 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6,

81 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5,

82 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4,

83 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xE1, 0xE2,

84 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,

85 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,

86 0xF9, 0xFA },

87 { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,

88 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,

89 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,

90 0xA1, 0xB1, 0xC1, 0x09, 0x23, 0x33, 0x52, 0xF0,

91 0x15, 0x62, 0x72, 0xD1, 0x0A, 0x16, 0x24, 0x34,

92 0xE1, 0x25, 0xF1, 0x17, 0x18, 0x19, 0x1A, 0x26,

93 0x27, 0x28, 0x29, 0x2A, 0x35, 0x36, 0x37, 0x38,

94 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,

95 0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,

96 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,

97 0x69, 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,

98 0x79, 0x7A, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,

99 0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96,

100 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5,

101 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4,

102 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3,

103 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2,

104 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA,

105 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9,

106 0xEA, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,

107 0xF9, 0xFA }

108 };

109

110 static const uint8_t vec_len_syms[2][4] = {

111 { 4, 2, 3, 1 },

112 { 4, 1, 2, 3 }

113 };

114

115 static const uint8_t mss4_vec_entry_vlc_lens[2][16] = {

116 { 0, 2, 2, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

117 { 0, 1, 5, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }

118 };

119

120 static const uint8_t mss4_vec_entry_vlc_syms[2][9] = {

121 { 0, 7, 6, 5, 8, 4, 3, 1, 2 },

122 { 0, 2, 3, 4, 5, 6, 7, 1, 8 }

123 };

124

125 #define MAX_ENTRIES 162

126

127 typedef struct MSS4Context {

128 AVFrame *pic;

129

130 VLC dc_vlc[2], ac_vlc[2];

131 VLC vec_entry_vlc[2];

132 int block[64];

133 uint8_t imgbuf[3][16 * 16];

134

135 int quality;

136 uint16_t quant_mat[2][64];

137

138 int *prev_dc[3];

139 int dc_stride[3];

140 int dc_cache[4][4];

141

142 int prev_vec[3][4];

143 } MSS4Context;

144

145 static av_cold int mss4_init_vlc(VLC *vlc, const uint8_t *lens,

146 const uint8_t *syms, int num_syms)

147 {

148 uint8_t bits[MAX_ENTRIES];

149 uint16_t codes[MAX_ENTRIES];

150 int i, j;

151 int prefix = 0, max_bits = 0, idx = 0;

152

153 for (i = 0; i < 16; i++) {

154 for (j = 0; j < lens[i]; j++) {

155 bits[idx] = i + 1;

156 codes[idx] = prefix++;

157 max_bits = i + 1;

158 idx++;

159 }

160 prefix <<= 1;

161 }

162

163 return ff_init_vlc_sparse(vlc, FFMIN(max_bits, 9), num_syms, bits, 1, 1,

164 codes, 2, 2, syms, 1, 1, 0);

165 }

166

167 static av_cold int mss4_init_vlcs(MSS4Context *ctx)

168 {

169 int ret, i;

170

171 for (i = 0; i < 2; i++) {

172 ret = mss4_init_vlc(&ctx->dc_vlc[i], mss4_dc_vlc_lens[i], NULL, 12);

173 if (ret)

174 return ret;

175 ret = mss4_init_vlc(&ctx->ac_vlc[i], mss4_ac_vlc_lens[i],

176 mss4_ac_vlc_syms[i], 162);

177 if (ret)

178 return ret;

179 ret = mss4_init_vlc(&ctx->vec_entry_vlc[i], mss4_vec_entry_vlc_lens[i],

180 mss4_vec_entry_vlc_syms[i], 9);

181 if (ret)

182 return ret;

183 }

184 return 0;

185 }

186

187 static av_cold void mss4_free_vlcs(MSS4Context *ctx)

188 {

189 int i;

190

191 for (i = 0; i < 2; i++) {

192 ff_free_vlc(&ctx->dc_vlc[i]);

193 ff_free_vlc(&ctx->ac_vlc[i]);

194 ff_free_vlc(&ctx->vec_entry_vlc[i]);

195 }

196 }

197

198 /* This function returns values in the range

199 * (-range + 1; -range/2] U [range/2; range - 1)

200 * i.e.

201 * nbits = 0 -> 0

202 * nbits = 1 -> -1, 1

203 * nbits = 2 -> -3, -2, 2, 3

204 */

205 static av_always_inline int get_coeff_bits(GetBitContext *gb, int nbits)

206 {

207 int val;

208

209 if (!nbits)

210 return 0;

211

212 val = get_bits(gb, nbits);

213 if (val < (1 << (nbits - 1)))

214 val -= (1 << nbits) - 1;

215

216 return val;

217 }

218

219 static inline int get_coeff(GetBitContext *gb, VLC *vlc)

220 {

221 int val = get_vlc2(gb, vlc->table, vlc->bits, 2);

222

223 return get_coeff_bits(gb, val);

224 }

225

226 static int mss4_decode_dct(GetBitContext *gb, VLC *dc_vlc, VLC *ac_vlc,

227 int *block, int *dc_cache,

228 int bx, int by, uint16_t *quant_mat)

229 {

230 int skip, val, pos = 1, zz_pos, dc;

231

232 memset(block, 0, sizeof(*block) * 64);

233

234 dc = get_coeff(gb, dc_vlc);

235 // DC prediction is the same as in MSS3

236 if (by) {

237 if (bx) {

238 int l, tl, t;

239

240 l = dc_cache[LEFT];

241 tl = dc_cache[TOP_LEFT];

242 t = dc_cache[TOP];

243

244 if (FFABS(t - tl) <= FFABS(l - tl))

245 dc += l;

246 else

247 dc += t;

248 } else {

249 dc += dc_cache[TOP];

250 }

251 } else if (bx) {

252 dc += dc_cache[LEFT];

253 }

254 dc_cache[LEFT] = dc;

255 block[0] = dc * quant_mat[0];

256

257 while (pos < 64) {

258 val = get_vlc2(gb, ac_vlc->table, 9, 2);

259 if (!val)

260 return 0;

261 if (val == -1)

262 return -1;

263 if (val == 0xF0) {

264 pos += 16;

265 continue;

266 }

267 skip = val >> 4;

268 val = get_coeff_bits(gb, val & 0xF);

269 pos += skip;

270 if (pos >= 64)

271 return -1;

272

273 zz_pos = ff_zigzag_direct[pos];

274 block[zz_pos] = val * quant_mat[zz_pos];

275 pos++;

276 }

277

278 return pos == 64 ? 0 : -1;

279 }

280

281 static int mss4_decode_dct_block(MSS4Context *c, GetBitContext *gb,

282 uint8_t *dst[3], int mb_x, int mb_y)

283 {

284 int i, j, k, ret;

285 uint8_t *out = dst[0];

286

287 for (j = 0; j < 2; j++) {

288 for (i = 0; i < 2; i++) {

289 int xpos = mb_x * 2 + i;

290 c->dc_cache[j][TOP_LEFT] = c->dc_cache[j][TOP];

291 c->dc_cache[j][TOP] = c->prev_dc[0][mb_x * 2 + i];

292 ret = mss4_decode_dct(gb, c->dc_vlc, c->ac_vlc, c->block,

293 c->dc_cache[j],

294 xpos, mb_y * 2 + j, c->quant_mat[0]);

295 if (ret)

296 return ret;

297 c->prev_dc[0][mb_x * 2 + i] = c->dc_cache[j][LEFT];

298

299 ff_mss34_dct_put(out + xpos * 8, c->pic->linesize[0],

300 c->block);

301 }

302 out += 8 * c->pic->linesize[0];

303 }

304

305 for (i = 1; i < 3; i++) {

306 c->dc_cache[i + 1][TOP_LEFT] = c->dc_cache[i + 1][TOP];

307 c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];

308 ret = mss4_decode_dct(gb, c->dc_vlc + 1, c->ac_vlc + 1,

309 c->block, c->dc_cache[i + 1], mb_x, mb_y,

310 c->quant_mat[1]);

311 if (ret)

312 return ret;

313 c->prev_dc[i][mb_x] = c->dc_cache[i + 1][LEFT];

314

315 ff_mss34_dct_put(c->imgbuf[i], 8, c->block);

316 out = dst[i] + mb_x * 16;

317 // Since the DCT block is coded as YUV420 and the whole frame as YUV444,

318 // we need to scale chroma.

319 for (j = 0; j < 16; j++) {

320 for (k = 0; k < 8; k++)

321 AV_WN16A(out + k * 2, c->imgbuf[i][k + (j & ~1) * 4] * 0x101);

322 out += c->pic->linesize[i];

323 }

324 }

325

326 return 0;

327 }

328

329 static void read_vec_pos(GetBitContext *gb, int *vec_pos, int *sel_flag,

330 int *sel_len, int *prev)

331 {

332 int i, y_flag = 0;

333

334 for (i = 2; i >= 0; i--) {

335 if (!sel_flag[i]) {

336 vec_pos[i] = 0;

337 continue;

338 }

339 if ((!i && !y_flag) || get_bits1(gb)) {

340 if (sel_len[i] > 0) {

341 int pval = prev[i];

342 vec_pos[i] = get_bits(gb, sel_len[i]);

343 if (vec_pos[i] >= pval)

344 vec_pos[i]++;

345 } else {

346 vec_pos[i] = !prev[i];

347 }

348 y_flag = 1;

349 } else {

350 vec_pos[i] = prev[i];

351 }

352 }

353 }

354

355 static int get_value_cached(GetBitContext *gb, int vec_pos, uint8_t *vec,

356 int vec_size, int component, int shift, int *prev)

357 {

358 if (vec_pos < vec_size)

359 return vec[vec_pos];

360 if (!get_bits1(gb))

361 return prev[component];

362 prev[component] = get_bits(gb, 8 - shift) << shift;

363 return prev[component];

364 }

365

366 #define MKVAL(vals) ((vals)[0] | ((vals)[1] << 3) | ((vals)[2] << 6))

367

368 /* Image mode - the hardest to comprehend MSS4 coding mode.

369 *

370 * In this mode all three 16x16 blocks are coded together with a method

371 * remotely similar to the methods employed in MSS1-MSS3.

372 * The idea is that every component has a vector of 1-4 most common symbols

373 * and an escape mode for reading new value from the bitstream. Decoding

374 * consists of retrieving pixel values from the vector or reading new ones

375 * from the bitstream; depending on flags read from the bitstream, these vector

376 * positions can be updated or reused from the state of the previous line

377 * or previous pixel.

378 */

379 static int mss4_decode_image_block(MSS4Context *ctx, GetBitContext *gb,

380 uint8_t *picdst[3], int mb_x, int mb_y)

381 {

382 uint8_t vec[3][4];

383 int vec_len[3];

384 int sel_len[3], sel_flag[3];

385 int i, j, k, mode, split;

386 int prev_vec1 = 0, prev_split = 0;

387 int vals[3] = { 0 };

388 int prev_pix[3] = { 0 };

389 int prev_mode[16] = { 0 };

390 uint8_t *dst[3];

391

392 const int val_shift = ctx->quality == 100 ? 0 : 2;

393

394 for (i = 0; i < 3; i++)

395 dst[i] = ctx->imgbuf[i];

396

397 for (i = 0; i < 3; i++) {

398 vec_len[i] = vec_len_syms[!!i][get_unary(gb, 0, 3)];

399 for (j = 0; j < vec_len[i]; j++) {

400 vec[i][j] = get_coeff(gb, &ctx->vec_entry_vlc[!!i]);

401 vec[i][j] += ctx->prev_vec[i][j];

402 ctx->prev_vec[i][j] = vec[i][j];

403 }

404 sel_flag[i] = vec_len[i] > 1;

405 sel_len[i] = vec_len[i] > 2 ? vec_len[i] - 2 : 0;

406 }

407

408 for (j = 0; j < 16; j++) {

409 if (get_bits1(gb)) {

410 split = 0;

411 if (get_bits1(gb)) {

412 prev_mode[0] = 0;

413 vals[0] = vals[1] = vals[2] = 0;

414 mode = 2;

415 } else {

416 mode = get_bits1(gb);

417 if (mode)

418 split = get_bits(gb, 4);

419 }

420 for (i = 0; i < 16; i++) {

421 if (mode <= 1) {

422 vals[0] = prev_mode[i] & 7;

423 vals[1] = (prev_mode[i] >> 3) & 7;

424 vals[2] = prev_mode[i] >> 6;

425 if (mode == 1 && i == split) {

426 read_vec_pos(gb, vals, sel_flag, sel_len, vals);

427 }

428 } else if (mode == 2) {

429 if (get_bits1(gb))

430 read_vec_pos(gb, vals, sel_flag, sel_len, vals);

431 }

432 for (k = 0; k < 3; k++)

433 *dst[k]++ = get_value_cached(gb, vals[k], vec[k],

434 vec_len[k], k,

435 val_shift, prev_pix);

436 prev_mode[i] = MKVAL(vals);

437 }

438 } else {

439 if (get_bits1(gb)) {

440 split = get_bits(gb, 4);

441 if (split >= prev_split)

442 split++;

443 prev_split = split;

444 } else {

445 split = prev_split;

446 }

447 if (split) {

448 vals[0] = prev_mode[0] & 7;

449 vals[1] = (prev_mode[0] >> 3) & 7;

450 vals[2] = prev_mode[0] >> 6;

451 for (i = 0; i < 3; i++) {

452 for (k = 0; k < split; k++) {

453 *dst[i]++ = get_value_cached(gb, vals[i], vec[i],

454 vec_len[i], i, val_shift,

455 prev_pix);

456 prev_mode[k] = MKVAL(vals);

457 }

458 }

459 }

460

461 if (split != 16) {

462 vals[0] = prev_vec1 & 7;

463 vals[1] = (prev_vec1 >> 3) & 7;

464 vals[2] = prev_vec1 >> 6;

465 if (get_bits1(gb)) {

466 read_vec_pos(gb, vals, sel_flag, sel_len, vals);

467 prev_vec1 = MKVAL(vals);

468 }

469 for (i = 0; i < 3; i++) {

470 for (k = 0; k < 16 - split; k++) {

471 *dst[i]++ = get_value_cached(gb, vals[i], vec[i],

472 vec_len[i], i, val_shift,

473 prev_pix);

474 prev_mode[split + k] = MKVAL(vals);

475 }

476 }

477 }

478 }

479 }

480

481 for (i = 0; i < 3; i++)

482 for (j = 0; j < 16; j++)

483 memcpy(picdst[i] + mb_x * 16 + j * ctx->pic->linesize[i],

484 ctx->imgbuf[i] + j * 16, 16);

485

486 return 0;

487 }

488

489 static inline void mss4_update_dc_cache(MSS4Context *c, int mb_x)

490 {

491 int i;

492

493 c->dc_cache[0][TOP] = c->prev_dc[0][mb_x * 2 + 1];

494 c->dc_cache[0][LEFT] = 0;

495 c->dc_cache[1][TOP] = 0;

496 c->dc_cache[1][LEFT] = 0;

497

498 for (i = 0; i < 2; i++)

499 c->prev_dc[0][mb_x * 2 + i] = 0;

500

501 for (i = 1; i < 3; i++) {

502 c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];

503 c->dc_cache[i + 1][LEFT] = 0;

504 c->prev_dc[i][mb_x] = 0;

505 }

506 }

507

508 static int mss4_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,

509 AVPacket *avpkt)

510 {

511 const uint8_t *buf = avpkt->data;

512 int buf_size = avpkt->size;

513 MSS4Context *c = avctx->priv_data;

514 GetBitContext gb;

515 GetByteContext bc;

516 uint8_t *dst[3];

517 int width, height, quality, frame_type;

518 int x, y, i, mb_width, mb_height, blk_type;

519 int ret;

520

521 if (buf_size < HEADER_SIZE) {

522 av_log(avctx, AV_LOG_ERROR,

523 "Frame should have at least %d bytes, got %d instead\n",

524 HEADER_SIZE, buf_size);

525 return AVERROR_INVALIDDATA;

526 }

527

528 bytestream2_init(&bc, buf, buf_size);

529 width = bytestream2_get_be16(&bc);

530 height = bytestream2_get_be16(&bc);

531 bytestream2_skip(&bc, 2);

532 quality = bytestream2_get_byte(&bc);

533 frame_type = bytestream2_get_byte(&bc);

534

535 if (width > avctx->width ||

536 height != avctx->height) {

537 av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d\n",

538 width, height);

539 return AVERROR_INVALIDDATA;

540 }

541 if (quality < 1 || quality > 100) {

542 av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);

543 return AVERROR_INVALIDDATA;

544 }

545 if ((frame_type & ~3) || frame_type == 3) {

546 av_log(avctx, AV_LOG_ERROR, "Invalid frame type %d\n", frame_type);

547 return AVERROR_INVALIDDATA;

548 }

549

550 if (frame_type != SKIP_FRAME && !bytestream2_get_bytes_left(&bc)) {

551 av_log(avctx, AV_LOG_ERROR,

552 "Empty frame found but it is not a skip frame.\n");

553 return AVERROR_INVALIDDATA;

554 }

555

556 if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)

557 return ret;

558 c->pic->key_frame = (frame_type == INTRA_FRAME);

559 c->pic->pict_type = (frame_type == INTRA_FRAME) ? AV_PICTURE_TYPE_I

560 : AV_PICTURE_TYPE_P;

561 if (frame_type == SKIP_FRAME) {

562 *got_frame = 1;

563 if ((ret = av_frame_ref(data, c->pic)) < 0)

564 return ret;

565

566 return buf_size;

567 }

568

569 if (c->quality != quality) {

570 c->quality = quality;

571 for (i = 0; i < 2; i++)

572 ff_mss34_gen_quant_mat(c->quant_mat[i], quality, !i);

573 }

574

575 init_get_bits8(&gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE));

576

577 mb_width = FFALIGN(width, 16) >> 4;

578 mb_height = FFALIGN(height, 16) >> 4;

579 dst[0] = c->pic->data[0];

580 dst[1] = c->pic->data[1];

581 dst[2] = c->pic->data[2];

582

583 memset(c->prev_vec, 0, sizeof(c->prev_vec));

584 for (y = 0; y < mb_height; y++) {

585 memset(c->dc_cache, 0, sizeof(c->dc_cache));

586 for (x = 0; x < mb_width; x++) {

587 blk_type = decode012(&gb);

588 switch (blk_type) {

589 case DCT_BLOCK:

590 if (mss4_decode_dct_block(c, &gb, dst, x, y) < 0) {

591 av_log(avctx, AV_LOG_ERROR,

592 "Error decoding DCT block %d,%d\n",

593 x, y);

594 return AVERROR_INVALIDDATA;

595 }

596 break;

597 case IMAGE_BLOCK:

598 if (mss4_decode_image_block(c, &gb, dst, x, y) < 0) {

599 av_log(avctx, AV_LOG_ERROR,

600 "Error decoding VQ block %d,%d\n",

601 x, y);

602 return AVERROR_INVALIDDATA;

603 }

604 break;

605 case SKIP_BLOCK:

606 if (frame_type == INTRA_FRAME) {

607 av_log(avctx, AV_LOG_ERROR, "Skip block in intra frame\n");

608 return AVERROR_INVALIDDATA;

609 }

610 break;

611 }

612 if (blk_type != DCT_BLOCK)

613 mss4_update_dc_cache(c, x);

614 }

615 dst[0] += c->pic->linesize[0] * 16;

616 dst[1] += c->pic->linesize[1] * 16;

617 dst[2] += c->pic->linesize[2] * 16;

618 }

619

620 if ((ret = av_frame_ref(data, c->pic)) < 0)

621 return ret;

622

623 *got_frame = 1;

624

625 return buf_size;

626 }

627

628 static av_cold int mss4_decode_end(AVCodecContext *avctx)

629 {

630 MSS4Context * const c = avctx->priv_data;

631 int i;

632

633 av_frame_free(&c->pic);

634 for (i = 0; i < 3; i++)

635 av_freep(&c->prev_dc[i]);

636 mss4_free_vlcs(c);

637

638 return 0;

639 }

640

641 static av_cold int mss4_decode_init(AVCodecContext *avctx)

642 {

643 MSS4Context * const c = avctx->priv_data;

644 int i;

645

646 if (mss4_init_vlcs(c)) {

647 av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");

648 mss4_free_vlcs(c);

649 return AVERROR(ENOMEM);

650 }

651 for (i = 0; i < 3; i++) {

652 c->dc_stride[i] = FFALIGN(avctx->width, 16) >> (2 + !!i);

653 c->prev_dc[i] = av_malloc(sizeof(**c->prev_dc) * c->dc_stride[i]);

654 if (!c->prev_dc[i]) {

655 av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");

656 mss4_free_vlcs(c);

657 return AVERROR(ENOMEM);

658 }

659 }

660

661 c->pic = av_frame_alloc();

662 if (!c->pic) {

663 mss4_decode_end(avctx);

664 return AVERROR(ENOMEM);

665 }

666

667 avctx->pix_fmt = AV_PIX_FMT_YUV444P;

668

669 return 0;

670 }

671

672 AVCodec ff_mts2_decoder = {

673 .name = "mts2",

674 .long_name = NULL_IF_CONFIG_SMALL("MS Expression Encoder Screen"),

675 .type = AVMEDIA_TYPE_VIDEO,

676 .id = AV_CODEC_ID_MTS2,

677 .priv_data_size = sizeof(MSS4Context),

678 .init = mss4_decode_init,

679 .close = mss4_decode_end,

680 .decode = mss4_decode_frame,

681 .capabilities = CODEC_CAP_DR1,

682 };

Generated on Sun Jul 20 2014 23:05:52 for FFmpeg by doxygen 1.8.2