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tscc2.c
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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 #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 };
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