FFmpeg: libavcodec/tscc2.c Source File

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libavcodec

tscc2.c

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1 /*

2 * TechSmith Screen Codec 2 (aka Dora) 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 * TechSmith Screen Codec 2 decoder

25 */

27 #include <inttypes.h>

29 #define BITSTREAM_READER_LE

30 #include "avcodec.h"

31 #include "get_bits.h"

32 #include "bytestream.h"

33 #include "internal.h"

34 #include "tscc2data.h"

36 typedef struct TSCC2Context {

37 AVCodecContext *avctx;

38 AVFrame *pic;

39 int mb_width, mb_height;

40 uint8_t *slice_quants;

41 int quant[2];

42 int q[2][3];

43 GetBitContext gb;

45 VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];

46 int block[16];

47 } TSCC2Context;

49 static av_cold void free_vlcs(TSCC2Context *c)

50 {

51 int i;

53 ff_free_vlc(&c->dc_vlc);

54 for (i = 0; i < NUM_VLC_SETS; i++) {

55 ff_free_vlc(c->nc_vlc + i);

56 ff_free_vlc(c->ac_vlc + i);

57 }

58 }

60 static av_cold int init_vlcs(TSCC2Context *c)

61 {

62 int i, ret;

64 ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT,

65 tscc2_dc_vlc_bits, 1, 1,

66 tscc2_dc_vlc_codes, 2, 2,

67 tscc2_dc_vlc_syms, 2, 2, INIT_VLC_LE);

68 if (ret)

69 return ret;

71 for (i = 0; i < NUM_VLC_SETS; i++) {

72 ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16,

73 tscc2_nc_vlc_bits[i], 1, 1,

74 tscc2_nc_vlc_codes[i], 2, 2,

75 tscc2_nc_vlc_syms, 1, 1, INIT_VLC_LE);

76 if (ret) {

77 free_vlcs(c);

78 return ret;

79 }

80 ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i],

81 tscc2_ac_vlc_bits[i], 1, 1,

82 tscc2_ac_vlc_codes[i], 2, 2,

83 tscc2_ac_vlc_syms[i], 2, 2, INIT_VLC_LE);

84 if (ret) {

85 free_vlcs(c);

86 return ret;

87 }

88 }

90 return 0;

91 }

93 #define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8)

94 #define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \

95 OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3)); \

96 OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1)); \

97 OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1)); \

98 OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3)); \

100 #define COL_OP(a, b) a = (b)

101 #define ROW_OP(a, b) a = ((b) + 0x20) >> 6

102

103 static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)

104 {

105 int i;

106 int tblk[4 * 4];

107 int t0, t1, t2, t3;

108

109 for (i = 0; i < 4; i++) {

110 t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);

111 t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);

112 t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);

113 t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);

114 DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],

115 tblk[2 * 4 + i], tblk[3 * 4 + i],

116 t0, t1, t2, t3, COL_OP);

117 }

118 for (i = 0; i < 4; i++) {

119 DCT1D(dst[0], dst[1], dst[2], dst[3],

120 tblk[i * 4 + 0], tblk[i * 4 + 1],

121 tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);

122 dst += stride;

123 }

124 }

125

126 static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,

127 uint8_t *dst, int stride, int plane)

128 {

129 GetBitContext *gb = &c->gb;

130 int prev_dc, dc, nc, ac, bpos, val;

131 int i, j, k, l;

132

133 if (get_bits1(gb)) {

134 if (get_bits1(gb)) {

135 val = get_bits(gb, 8);

136 for (i = 0; i < 8; i++, dst += stride)

137 memset(dst, val, 16);

138 } else {

139 if (get_bits_left(gb) < 16 * 8 * 8)

140 return AVERROR_INVALIDDATA;

141 for (i = 0; i < 8; i++) {

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

143 dst[j] = get_bits(gb, 8);

144 dst += stride;

145 }

146 }

147 return 0;

148 }

149

150 prev_dc = 0;

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

152 for (k = 0; k < 4; k++) {

153 if (!(j | k)) {

154 dc = get_bits(gb, 8);

155 } else {

156 dc = get_vlc2(gb, c->dc_vlc.table, 9, 2);

157 if (dc == -1)

158 return AVERROR_INVALIDDATA;

159 if (dc == 0x100)

160 dc = get_bits(gb, 8);

161 }

162 dc = (dc + prev_dc) & 0xFF;

163 prev_dc = dc;

164 c->block[0] = dc;

165

166 nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1);

167 if (nc == -1)

168 return AVERROR_INVALIDDATA;

169

170 bpos = 1;

171 memset(c->block + 1, 0, 15 * sizeof(*c->block));

172 for (l = 0; l < nc; l++) {

173 ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2);

174 if (ac == -1)

175 return AVERROR_INVALIDDATA;

176 if (ac == 0x1000)

177 ac = get_bits(gb, 12);

178 bpos += ac & 0xF;

179 if (bpos >= 16)

180 return AVERROR_INVALIDDATA;

181 val = sign_extend(ac >> 4, 8);

182 c->block[tscc2_zigzag[bpos++]] = val;

183 }

184 tscc2_idct4_put(c->block, q, dst + k * 4, stride);

185 }

186 dst += 4 * stride;

187 }

188 return 0;

189 }

190

191 static int tscc2_decode_slice(TSCC2Context *c, int mb_y,

192 const uint8_t *buf, int buf_size)

193 {

194 int i, mb_x, q, ret;

195 int off;

196

197 if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0)

198 return ret;

199

200 for (mb_x = 0; mb_x < c->mb_width; mb_x++) {

201 q = c->slice_quants[mb_x + c->mb_width * mb_y];

202

203 if (q == 0 || q == 3) // skip block

204 continue;

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

206 off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];

207 ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,

208 c->pic->data[i] + off, c->pic->linesize[i], i);

209 if (ret)

210 return ret;

211 }

212 }

213

214 return 0;

215 }

216

217 static int tscc2_decode_frame(AVCodecContext *avctx, void *data,

218 int *got_frame, AVPacket *avpkt)

219 {

220 const uint8_t *buf = avpkt->data;

221 int buf_size = avpkt->size;

222 TSCC2Context *c = avctx->priv_data;

223 GetByteContext gb;

224 uint32_t frame_type, size;

225 int i, val, len, pos = 0;

226 int num_mb = c->mb_width * c->mb_height;

227 int ret;

228

229 bytestream2_init(&gb, buf, buf_size);

230 frame_type = bytestream2_get_byte(&gb);

231 if (frame_type > 1) {

232 av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n",

233 frame_type);

234 return AVERROR_INVALIDDATA;

235 }

236

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

238 return ret;

239 }

240

241 if (frame_type == 0) {

242 *got_frame = 1;

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

244 return ret;

245

246 return buf_size;

247 }

248

249 if (bytestream2_get_bytes_left(&gb) < 4) {

250 av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");

251 return AVERROR_INVALIDDATA;

252 }

253

254 c->quant[0] = bytestream2_get_byte(&gb);

255 c->quant[1] = bytestream2_get_byte(&gb);

256 if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||

257 c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {

258 av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",

259 c->quant[0], c->quant[1]);

260 return AVERROR_INVALIDDATA;

261 }

262

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

264 c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];

265 c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];

266 }

267

268 bytestream2_skip(&gb, 1);

269

270 size = bytestream2_get_le32(&gb);

271 if (size > bytestream2_get_bytes_left(&gb)) {

272 av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");

273 return AVERROR_INVALIDDATA;

274 }

275

276 for (i = 0; i < size; i++) {

277 val = bytestream2_get_byte(&gb);

278 len = val & 0x3F;

279 val >>= 6;

280 if (pos + len > num_mb) {

281 av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");

282 return AVERROR_INVALIDDATA;

283 }

284 memset(c->slice_quants + pos, val, len);

285 pos += len;

286 }

287 if (pos < num_mb) {

288 av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",

289 pos, num_mb);

290 return AVERROR_INVALIDDATA;

291 }

292

293 for (i = 0; i < c->mb_height; i++) {

294 size = bytestream2_peek_byte(&gb);

295 if (size & 1) {

296 size = bytestream2_get_byte(&gb) - 1;

297 } else {

298 size = bytestream2_get_le32(&gb) >> 1;

299 }

300 if (!size) {

301 int skip_row = 1, j, off = i * c->mb_width;

302 for (j = 0; j < c->mb_width; j++) {

303 if (c->slice_quants[off + j] == 1 ||

304 c->slice_quants[off + j] == 2) {

305 skip_row = 0;

306 break;

307 }

308 }

309 if (!skip_row) {

310 av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");

311 return AVERROR_INVALIDDATA;

312 }

313 }

314 if (bytestream2_get_bytes_left(&gb) < size) {

315 av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n",

316 size, bytestream2_get_bytes_left(&gb));

317 return AVERROR_INVALIDDATA;

318 }

319 ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);

320 if (ret) {

321 av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);

322 return ret;

323 }

324 bytestream2_skip(&gb, size);

325 }

326

327 *got_frame = 1;

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

329 return ret;

330

331 /* always report that the buffer was completely consumed */

332 return buf_size;

333 }

334

335 static av_cold int tscc2_decode_end(AVCodecContext *avctx)

336 {

337 TSCC2Context * const c = avctx->priv_data;

338

339 av_frame_free(&c->pic);

340 av_freep(&c->slice_quants);

341 free_vlcs(c);

342

343 return 0;

344 }

345

346 static av_cold int tscc2_decode_init(AVCodecContext *avctx)

347 {

348 TSCC2Context * const c = avctx->priv_data;

349 int ret;

350

351 c->avctx = avctx;

352

353 avctx->pix_fmt = AV_PIX_FMT_YUV444P;

354

355 if ((ret = init_vlcs(c)) < 0) {

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

357 return ret;

358 }

359

360 c->mb_width = FFALIGN(avctx->width, 16) >> 4;

361 c->mb_height = FFALIGN(avctx->height, 8) >> 3;

362 c->slice_quants = av_malloc(c->mb_width * c->mb_height);

363 if (!c->slice_quants) {

364 av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");

365 free_vlcs(c);

366 return AVERROR(ENOMEM);

367 }

368

369 c->pic = av_frame_alloc();

370 if (!c->pic) {

371 tscc2_decode_end(avctx);

372 return AVERROR(ENOMEM);

373 }

374

375 return 0;

376 }

377

378 AVCodec ff_tscc2_decoder = {

379 .name = "tscc2",

380 .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),

381 .type = AVMEDIA_TYPE_VIDEO,

382 .id = AV_CODEC_ID_TSCC2,

383 .priv_data_size = sizeof(TSCC2Context),

384 .init = tscc2_decode_init,

385 .close = tscc2_decode_end,

386 .decode = tscc2_decode_frame,

387 .capabilities = CODEC_CAP_DR1,

388 };

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