libavcodec/tscc2.c

   1 /*
   2  * TechSmith Screen Codec 2 (aka Dora) decoder
   3  * Copyright (c) 2012 Konstantin Shishkov
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 #define BITSTREAM_READER_LE
  28 #include "avcodec.h"
  29 #include "get_bits.h"
  30 #include "bytestream.h"
  31 #include "tscc2data.h"
  32
  33 typedef struct TSCC2Context {
  34     AVCodecContext *avctx;
  35     AVFrame        pic;
  36     int            mb_width, mb_height;
  37     uint8_t        *slice_quants;
  38     int            quant[2];
  39     int            q[2][3];
  40     GetBitContext  gb;
  41
  42     VLC            dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
  43     int            block[16];
  44 } TSCC2Context;
  45
  46 static av_cold void free_vlcs(TSCC2Context *c)
  47 {
  48     int i;
  49
  50     ff_free_vlc(&c->dc_vlc);
  51     for (i = 0; i < NUM_VLC_SETS; i++) {
  52         ff_free_vlc(c->nc_vlc + i);
  53         ff_free_vlc(c->ac_vlc + i);
  54     }
  55 }
  56
  57 static av_cold int init_vlcs(TSCC2Context *c)
  58 {
  59     int i, ret;
  60
  61     ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT,
  62                              tscc2_dc_vlc_bits,  1, 1,
  63                              tscc2_dc_vlc_codes, 2, 2,
  64                              tscc2_dc_vlc_syms,  2, 2, INIT_VLC_LE);
  65     if (ret)
  66         return ret;
  67
  68     for (i = 0; i < NUM_VLC_SETS; i++) {
  69         ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16,
  70                                  tscc2_nc_vlc_bits[i],  1, 1,
  71                                  tscc2_nc_vlc_codes[i], 2, 2,
  72                                  tscc2_nc_vlc_syms,     1, 1, INIT_VLC_LE);
  73         if (ret) {
  74             free_vlcs(c);
  75             return ret;
  76         }
  77         ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i],
  78                                  tscc2_ac_vlc_bits[i],  1, 1,
  79                                  tscc2_ac_vlc_codes[i], 2, 2,
  80                                  tscc2_ac_vlc_syms[i],  2, 2, INIT_VLC_LE);
  81         if (ret) {
  82             free_vlcs(c);
  83             return ret;
  84         }
  85     }
  86
  87     return 0;
  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
 100 static 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
 123 static 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, c->dc_vlc.table, 9, 2);
 154                 if (dc == -1)
 155                     return AVERROR_INVALIDDATA;
 156                 if (dc == 0x100)
 157                     dc = get_bits(gb, 8);
 158             }
 159             dc          = (dc + prev_dc) & 0xFF;
 160             prev_dc     = dc;
 161             c->block[0] = dc;
 162
 163             nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1);
 164             if (nc == -1)
 165                 return AVERROR_INVALIDDATA;
 166
 167             bpos = 1;
 168             memset(c->block + 1, 0, 15 * sizeof(*c->block));
 169             for (l = 0; l < nc; l++) {
 170                 ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2);
 171                 if (ac == -1)
 172                     return AVERROR_INVALIDDATA;
 173                 if (ac == 0x1000)
 174                     ac = get_bits(gb, 12);
 175                 bpos += ac & 0xF;
 176                 if (bpos >= 16)
 177                     return AVERROR_INVALIDDATA;
 178                 val = sign_extend(ac >> 4, 8);
 179                 c->block[tscc2_zigzag[bpos++]] = val;
 180             }
 181             tscc2_idct4_put(c->block, q, dst + k * 4, stride);
 182         }
 183         dst += 4 * stride;
 184     }
 185     return 0;
 186 }
 187
 188 static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
 189                               const uint8_t *buf, int buf_size)
 190 {
 191     int i, mb_x, q, ret;
 192     int off;
 193
 194     init_get_bits(&c->gb, buf, buf_size * 8);
 195
 196     for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
 197         q = c->slice_quants[mb_x + c->mb_width * mb_y];
 198
 199         if (q == 0 || q == 3) // skip block
 200             continue;
 201         for (i = 0; i < 3; i++) {
 202             off = mb_x * 16 + mb_y * 8 * c->pic.linesize[i];
 203             ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,
 204                                   c->pic.data[i] + off, c->pic.linesize[i], i);
 205             if (ret)
 206                 return ret;
 207         }
 208     }
 209
 210     return 0;
 211 }
 212
 213 static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
 214                               int *got_frame, AVPacket *avpkt)
 215 {
 216     const uint8_t *buf = avpkt->data;
 217     int buf_size = avpkt->size;
 218     TSCC2Context *c = avctx->priv_data;
 219     GetByteContext gb;
 220     uint32_t frame_type, size;
 221     int i, val, len, pos = 0;
 222     int num_mb = c->mb_width * c->mb_height;
 223     int ret;
 224
 225     bytestream2_init(&gb, buf, buf_size);
 226     frame_type = bytestream2_get_byte(&gb);
 227     if (frame_type > 1) {
 228         av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %d\n", frame_type);
 229         return AVERROR_INVALIDDATA;
 230     }
 231
 232     c->pic.reference    = 3;
 233     c->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
 234                           FF_BUFFER_HINTS_REUSABLE;
 235     if ((ret = avctx->reget_buffer(avctx, &c->pic)) < 0) {
 236         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 237         return ret;
 238     }
 239
 240     if (frame_type == 0) {
 241         *got_frame      = 1;
 242         *(AVFrame*)data = c->pic;
 243
 244         return buf_size;
 245     }
 246
 247     if (bytestream2_get_bytes_left(&gb) < 4) {
 248         av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
 249         return AVERROR_INVALIDDATA;
 250     }
 251
 252     c->quant[0] = bytestream2_get_byte(&gb);
 253     c->quant[1] = bytestream2_get_byte(&gb);
 254     if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
 255         c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {
 256         av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",
 257                c->quant[0], c->quant[1]);
 258         return AVERROR_INVALIDDATA;
 259     }
 260
 261     for (i = 0; i < 3; i++) {
 262         c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
 263         c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
 264     }
 265
 266     bytestream2_skip(&gb, 1);
 267
 268     size = bytestream2_get_le32(&gb);
 269     if (size > bytestream2_get_bytes_left(&gb)) {
 270         av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");
 271         return AVERROR_INVALIDDATA;
 272     }
 273
 274     for (i = 0; i < size; i++) {
 275         val   = bytestream2_get_byte(&gb);
 276         len   = val & 0x3F;
 277         val >>= 6;
 278         if (pos + len > num_mb) {
 279             av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
 280             return AVERROR_INVALIDDATA;
 281         }
 282         memset(c->slice_quants + pos, val, len);
 283         pos += len;
 284     }
 285     if (pos < num_mb) {
 286         av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",
 287                pos, num_mb);
 288         return AVERROR_INVALIDDATA;
 289     }
 290
 291     for (i = 0; i < c->mb_height; i++) {
 292         size = bytestream2_peek_byte(&gb);
 293         if (size & 1) {
 294             size = bytestream2_get_byte(&gb) - 1;
 295         } else {
 296             size = bytestream2_get_le32(&gb) >> 1;
 297         }
 298         if (!size) {
 299             int skip_row = 1, j, off = i * c->mb_width;
 300             for (j = 0; j < c->mb_width; j++) {
 301                 if (c->slice_quants[off + j] == 1 ||
 302                     c->slice_quants[off + j] == 2) {
 303                     skip_row = 0;
 304                     break;
 305                 }
 306             }
 307             if (!skip_row) {
 308                 av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
 309                 return AVERROR_INVALIDDATA;
 310             }
 311         }
 312         if (bytestream2_get_bytes_left(&gb) < size) {
 313             av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%d/%d)\n",
 314                    size, bytestream2_get_bytes_left(&gb));
 315             return AVERROR_INVALIDDATA;
 316         }
 317         ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
 318         if (ret) {
 319             av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
 320             return ret;
 321         }
 322         bytestream2_skip(&gb, size);
 323     }
 324
 325     *got_frame      = 1;
 326     *(AVFrame*)data = c->pic;
 327
 328     /* always report that the buffer was completely consumed */
 329     return buf_size;
 330 }
 331
 332 static av_cold int tscc2_decode_init(AVCodecContext *avctx)
 333 {
 334     TSCC2Context * const c = avctx->priv_data;
 335     int ret;
 336
 337     c->avctx = avctx;
 338
 339     avctx->pix_fmt = AV_PIX_FMT_YUV444P;
 340
 341     if ((ret = init_vlcs(c)) < 0) {
 342         av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
 343         return ret;
 344     }
 345
 346     c->mb_width     = FFALIGN(avctx->width,  16) >> 4;
 347     c->mb_height    = FFALIGN(avctx->height,  8) >> 3;
 348     c->slice_quants = av_malloc(c->mb_width * c->mb_height);
 349     if (!c->slice_quants) {
 350         av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
 351         free_vlcs(c);
 352         return AVERROR(ENOMEM);
 353     }
 354
 355     avctx->coded_frame = &c->pic;
 356
 357     return 0;
 358 }
 359
 360 static av_cold int tscc2_decode_end(AVCodecContext *avctx)
 361 {
 362     TSCC2Context * const c = avctx->priv_data;
 363
 364     if (c->pic.data[0])
 365         avctx->release_buffer(avctx, &c->pic);
 366     av_freep(&c->slice_quants);
 367     free_vlcs(c);
 368
 369     return 0;
 370 }
 371
 372 AVCodec ff_tscc2_decoder = {
 373     .name           = "tscc2",
 374     .type           = AVMEDIA_TYPE_VIDEO,
 375     .id             = AV_CODEC_ID_TSCC2,
 376     .priv_data_size = sizeof(TSCC2Context),
 377     .init           = tscc2_decode_init,
 378     .close          = tscc2_decode_end,
 379     .decode         = tscc2_decode_frame,
 380     .capabilities   = CODEC_CAP_DR1,
 381     .long_name      = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),
 382 };