1/* 2 * TechSmith Screen Codec 2 (aka Dora) decoder 3 * Copyright (c) 2012 Konstantin Shishkov 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 */ 21 22/** 23 * @file 24 * TechSmith Screen Codec 2 decoder 25 */ 26 27#include <inttypes.h> 28 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" 35 36typedef 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; 44 45 VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS]; 46 int block[16]; 47} TSCC2Context; 48 49static av_cold void free_vlcs(TSCC2Context *c) 50{ 51 int i; 52 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} 59 60static av_cold int init_vlcs(TSCC2Context *c) 61{ 62 int i, ret; 63 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; 70 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 } 89 90 return 0; 91} 92 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)); \ 99 100#define COL_OP(a, b) a = (b) 101#define ROW_OP(a, b) a = ((b) + 0x20) >> 6 102 103static 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 126static 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 191static 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 217static 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 335static 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 346static 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 378AVCodec 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}; 389