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#include "libavutil/thread.h" 30 31#define BITSTREAM_READER_LE 32#include "avcodec.h" 33#include "bytestream.h" 34#include "codec_internal.h" 35#include "get_bits.h" 36#include "internal.h" 37#include "mathops.h" 38#include "tscc2data.h" 39 40#define TSCC2_VLC_BITS 9 41 42typedef struct TSCC2Context { 43 AVCodecContext *avctx; 44 AVFrame *pic; 45 int mb_width, mb_height; 46 uint8_t *slice_quants; 47 int quant[2]; 48 int q[2][3]; 49 GetBitContext gb; 50 51 int block[16]; 52} TSCC2Context; 53 54static VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS]; 55 56static av_cold void tscc2_init_vlc(VLC *vlc, int *offset, int nb_codes, 57 const uint8_t *lens, const void *syms, 58 int sym_length) 59{ 60 static VLCElem vlc_buf[15442]; 61 62 vlc->table = &vlc_buf[*offset]; 63 vlc->table_allocated = FF_ARRAY_ELEMS(vlc_buf) - *offset; 64 ff_init_vlc_from_lengths(vlc, TSCC2_VLC_BITS, nb_codes, 65 lens, 1, syms, sym_length, sym_length, 0, 66 INIT_VLC_STATIC_OVERLONG | INIT_VLC_OUTPUT_LE, NULL); 67 *offset += vlc->table_size; 68} 69 70static av_cold void tscc2_init_vlcs(void) 71{ 72 const uint16_t *ac_vlc_syms = tscc2_ac_vlc_syms; 73 const uint8_t *ac_vlc_lens = tscc2_ac_vlc_lens; 74 int i, offset = 0; 75 76 tscc2_init_vlc(&dc_vlc, &offset, DC_VLC_COUNT, 77 tscc2_dc_vlc_lens, tscc2_dc_vlc_syms, 2); 78 79 for (i = 0; i < NUM_VLC_SETS; i++) { 80 tscc2_init_vlc(&nc_vlc[i], &offset, 16, 81 tscc2_nc_vlc_lens[i], tscc2_nc_vlc_syms[i], 1); 82 83 tscc2_init_vlc(&ac_vlc[i], &offset, tscc2_ac_vlc_sizes[i], 84 ac_vlc_lens, ac_vlc_syms, 2); 85 ac_vlc_lens += tscc2_ac_vlc_sizes[i]; 86 ac_vlc_syms += tscc2_ac_vlc_sizes[i]; 87 } 88} 89 90#define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8) 91#define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \ 92 OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3)); \ 93 OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1)); \ 94 OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1)); \ 95 OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3)); \ 96 97#define COL_OP(a, b) a = (b) 98#define ROW_OP(a, b) a = ((b) + 0x20) >> 6 99 100static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride) 101{ 102 int i; 103 int tblk[4 * 4]; 104 int t0, t1, t2, t3; 105 106 for (i = 0; i < 4; i++) { 107 t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]); 108 t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]); 109 t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]); 110 t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]); 111 DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i], 112 tblk[2 * 4 + i], tblk[3 * 4 + i], 113 t0, t1, t2, t3, COL_OP); 114 } 115 for (i = 0; i < 4; i++) { 116 DCT1D(dst[0], dst[1], dst[2], dst[3], 117 tblk[i * 4 + 0], tblk[i * 4 + 1], 118 tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP); 119 dst += stride; 120 } 121} 122 123static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set, 124 uint8_t *dst, int stride, int plane) 125{ 126 GetBitContext *gb = &c->gb; 127 int prev_dc, dc, nc, ac, bpos, val; 128 int i, j, k, l; 129 130 if (get_bits1(gb)) { 131 if (get_bits1(gb)) { 132 val = get_bits(gb, 8); 133 for (i = 0; i < 8; i++, dst += stride) 134 memset(dst, val, 16); 135 } else { 136 if (get_bits_left(gb) < 16 * 8 * 8) 137 return AVERROR_INVALIDDATA; 138 for (i = 0; i < 8; i++) { 139 for (j = 0; j < 16; j++) 140 dst[j] = get_bits(gb, 8); 141 dst += stride; 142 } 143 } 144 return 0; 145 } 146 147 prev_dc = 0; 148 for (j = 0; j < 2; j++) { 149 for (k = 0; k < 4; k++) { 150 if (!(j | k)) { 151 dc = get_bits(gb, 8); 152 } else { 153 dc = get_vlc2(gb, dc_vlc.table, TSCC2_VLC_BITS, 2); 154 if (dc == 0x100) 155 dc = get_bits(gb, 8); 156 } 157 dc = (dc + prev_dc) & 0xFF; 158 prev_dc = dc; 159 c->block[0] = dc; 160 161 nc = get_vlc2(gb, nc_vlc[vlc_set].table, TSCC2_VLC_BITS, 1); 162 163 bpos = 1; 164 memset(c->block + 1, 0, 15 * sizeof(*c->block)); 165 for (l = 0; l < nc; l++) { 166 ac = get_vlc2(gb, ac_vlc[vlc_set].table, TSCC2_VLC_BITS, 2); 167 if (ac == 0x1000) 168 ac = get_bits(gb, 12); 169 bpos += ac & 0xF; 170 if (bpos >= 16) 171 return AVERROR_INVALIDDATA; 172 val = sign_extend(ac >> 4, 8); 173 c->block[ff_zigzag_scan[bpos++]] = val; 174 } 175 tscc2_idct4_put(c->block, q, dst + k * 4, stride); 176 } 177 dst += 4 * stride; 178 } 179 return 0; 180} 181 182static int tscc2_decode_slice(TSCC2Context *c, int mb_y, 183 const uint8_t *buf, int buf_size) 184{ 185 int i, mb_x, q, ret; 186 int off; 187 188 if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0) 189 return ret; 190 191 for (mb_x = 0; mb_x < c->mb_width; mb_x++) { 192 q = c->slice_quants[mb_x + c->mb_width * mb_y]; 193 194 if (q == 0 || q == 3) // skip block 195 continue; 196 for (i = 0; i < 3; i++) { 197 off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i]; 198 ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2, 199 c->pic->data[i] + off, c->pic->linesize[i], i); 200 if (ret) 201 return ret; 202 } 203 } 204 205 return 0; 206} 207 208static int tscc2_decode_frame(AVCodecContext *avctx, AVFrame *rframe, 209 int *got_frame, AVPacket *avpkt) 210{ 211 const uint8_t *buf = avpkt->data; 212 int buf_size = avpkt->size; 213 TSCC2Context *c = avctx->priv_data; 214 GetByteContext gb; 215 uint32_t frame_type, size; 216 int i, val, len, pos = 0; 217 int num_mb = c->mb_width * c->mb_height; 218 int ret; 219 220 bytestream2_init(&gb, buf, buf_size); 221 frame_type = bytestream2_get_byte(&gb); 222 if (frame_type > 1) { 223 av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n", 224 frame_type); 225 return AVERROR_INVALIDDATA; 226 } 227 228 if (frame_type == 0) { 229 // Skip duplicate frames 230 return buf_size; 231 } 232 233 if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0) { 234 return ret; 235 } 236 237 if (bytestream2_get_bytes_left(&gb) < 4) { 238 av_log(avctx, AV_LOG_ERROR, "Frame is too short\n"); 239 return AVERROR_INVALIDDATA; 240 } 241 242 c->quant[0] = bytestream2_get_byte(&gb); 243 c->quant[1] = bytestream2_get_byte(&gb); 244 if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 || 245 c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) { 246 av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n", 247 c->quant[0], c->quant[1]); 248 return AVERROR_INVALIDDATA; 249 } 250 251 for (i = 0; i < 3; i++) { 252 c->q[0][i] = tscc2_quants[c->quant[0] - 2][i]; 253 c->q[1][i] = tscc2_quants[c->quant[1] - 2][i]; 254 } 255 256 bytestream2_skip(&gb, 1); 257 258 size = bytestream2_get_le32(&gb); 259 if (size > bytestream2_get_bytes_left(&gb)) { 260 av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n"); 261 return AVERROR_INVALIDDATA; 262 } 263 264 for (i = 0; i < size; i++) { 265 val = bytestream2_get_byte(&gb); 266 len = val & 0x3F; 267 val >>= 6; 268 if (pos + len > num_mb) { 269 av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n"); 270 return AVERROR_INVALIDDATA; 271 } 272 memset(c->slice_quants + pos, val, len); 273 pos += len; 274 } 275 if (pos < num_mb) { 276 av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n", 277 pos, num_mb); 278 return AVERROR_INVALIDDATA; 279 } 280 281 for (i = 0; i < c->mb_height; i++) { 282 size = bytestream2_peek_byte(&gb); 283 if (size & 1) { 284 size = bytestream2_get_byte(&gb) - 1; 285 } else { 286 size = bytestream2_get_le32(&gb) >> 1; 287 } 288 if (!size) { 289 int skip_row = 1, j, off = i * c->mb_width; 290 for (j = 0; j < c->mb_width; j++) { 291 if (c->slice_quants[off + j] == 1 || 292 c->slice_quants[off + j] == 2) { 293 skip_row = 0; 294 break; 295 } 296 } 297 if (!skip_row) { 298 av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n"); 299 return AVERROR_INVALIDDATA; 300 } 301 } 302 if (bytestream2_get_bytes_left(&gb) < size) { 303 av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n", 304 size, bytestream2_get_bytes_left(&gb)); 305 return AVERROR_INVALIDDATA; 306 } 307 ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size); 308 if (ret) { 309 av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i); 310 return ret; 311 } 312 bytestream2_skip(&gb, size); 313 } 314 315 *got_frame = 1; 316 if ((ret = av_frame_ref(rframe, c->pic)) < 0) 317 return ret; 318 319 /* always report that the buffer was completely consumed */ 320 return buf_size; 321} 322 323static av_cold int tscc2_decode_end(AVCodecContext *avctx) 324{ 325 TSCC2Context * const c = avctx->priv_data; 326 327 av_frame_free(&c->pic); 328 av_freep(&c->slice_quants); 329 330 return 0; 331} 332 333static av_cold int tscc2_decode_init(AVCodecContext *avctx) 334{ 335 TSCC2Context * const c = avctx->priv_data; 336 static AVOnce init_static_once = AV_ONCE_INIT; 337 338 c->avctx = avctx; 339 340 avctx->pix_fmt = AV_PIX_FMT_YUV444P; 341 342 c->mb_width = FFALIGN(avctx->width, 16) >> 4; 343 c->mb_height = FFALIGN(avctx->height, 8) >> 3; 344 c->slice_quants = av_malloc(c->mb_width * c->mb_height); 345 if (!c->slice_quants) { 346 av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n"); 347 return AVERROR(ENOMEM); 348 } 349 350 c->pic = av_frame_alloc(); 351 if (!c->pic) 352 return AVERROR(ENOMEM); 353 354 ff_thread_once(&init_static_once, tscc2_init_vlcs); 355 356 return 0; 357} 358 359const FFCodec ff_tscc2_decoder = { 360 .p.name = "tscc2", 361 .p.long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"), 362 .p.type = AVMEDIA_TYPE_VIDEO, 363 .p.id = AV_CODEC_ID_TSCC2, 364 .priv_data_size = sizeof(TSCC2Context), 365 .init = tscc2_decode_init, 366 .close = tscc2_decode_end, 367 FF_CODEC_DECODE_CB(tscc2_decode_frame), 368 .p.capabilities = AV_CODEC_CAP_DR1, 369 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE, 370}; 371