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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 "internal.h"
32 #include "tscc2data.h"
33 
34 typedef struct TSCC2Context {
35  AVCodecContext *avctx;
36  AVFrame *pic;
37  int mb_width, mb_height;
38  uint8_t *slice_quants;
39  int quant[2];
40  int q[2][3];
41  GetBitContext gb;
42 
43  VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
44  int block[16];
45 } TSCC2Context;
46 
47 static av_cold void free_vlcs(TSCC2Context *c)
48 {
49  int i;
50 
51  ff_free_vlc(&c->dc_vlc);
52  for (i = 0; i < NUM_VLC_SETS; i++) {
53  ff_free_vlc(c->nc_vlc + i);
54  ff_free_vlc(c->ac_vlc + i);
55  }
56 }
57 
58 static av_cold int init_vlcs(TSCC2Context *c)
59 {
60  int i, ret;
61 
62  ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT,
63  tscc2_dc_vlc_bits, 1, 1,
64  tscc2_dc_vlc_codes, 2, 2,
65  tscc2_dc_vlc_syms, 2, 2, INIT_VLC_LE);
66  if (ret)
67  return ret;
68 
69  for (i = 0; i < NUM_VLC_SETS; i++) {
70  ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16,
71  tscc2_nc_vlc_bits[i], 1, 1,
72  tscc2_nc_vlc_codes[i], 2, 2,
73  tscc2_nc_vlc_syms, 1, 1, INIT_VLC_LE);
74  if (ret) {
75  free_vlcs(c);
76  return ret;
77  }
78  ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i],
79  tscc2_ac_vlc_bits[i], 1, 1,
80  tscc2_ac_vlc_codes[i], 2, 2,
81  tscc2_ac_vlc_syms[i], 2, 2, INIT_VLC_LE);
82  if (ret) {
83  free_vlcs(c);
84  return ret;
85  }
86  }
87 
88  return 0;
89 }
90 
91 #define DEQUANT(val, q) ((q * val + 0x80) >> 8)
92 #define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
93  OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3)); \
94  OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1)); \
95  OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1)); \
96  OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3)); \
97 
98 #define COL_OP(a, b) a = b
99 #define ROW_OP(a, b) a = ((b) + 0x20) >> 6
100 
101 static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
102 {
103  int i;
104  int tblk[4 * 4];
105  int t0, t1, t2, t3;
106 
107  for (i = 0; i < 4; i++) {
108  t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
109  t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
110  t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
111  t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
112  DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
113  tblk[2 * 4 + i], tblk[3 * 4 + i],
114  t0, t1, t2, t3, COL_OP);
115  }
116  for (i = 0; i < 4; i++) {
117  DCT1D(dst[0], dst[1], dst[2], dst[3],
118  tblk[i * 4 + 0], tblk[i * 4 + 1],
119  tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
120  dst += stride;
121  }
122 }
123 
124 static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
125  uint8_t *dst, int stride, int plane)
126 {
127  GetBitContext *gb = &c->gb;
128  int prev_dc, dc, nc, ac, bpos, val;
129  int i, j, k, l;
130 
131  if (get_bits1(gb)) {
132  if (get_bits1(gb)) {
133  val = get_bits(gb, 8);
134  for (i = 0; i < 8; i++, dst += stride)
135  memset(dst, val, 16);
136  } else {
137  if (get_bits_left(gb) < 16 * 8 * 8)
138  return AVERROR_INVALIDDATA;
139  for (i = 0; i < 8; i++) {
140  for (j = 0; j < 16; j++)
141  dst[j] = get_bits(gb, 8);
142  dst += stride;
143  }
144  }
145  return 0;
146  }
147 
148  prev_dc = 0;
149  for (j = 0; j < 2; j++) {
150  for (k = 0; k < 4; k++) {
151  if (!(j | k)) {
152  dc = get_bits(gb, 8);
153  } else {
154  dc = get_vlc2(gb, c->dc_vlc.table, 9, 2);
155  if (dc == -1)
156  return AVERROR_INVALIDDATA;
157  if (dc == 0x100)
158  dc = get_bits(gb, 8);
159  }
160  dc = (dc + prev_dc) & 0xFF;
161  prev_dc = dc;
162  c->block[0] = dc;
163 
164  nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1);
165  if (nc == -1)
166  return AVERROR_INVALIDDATA;
167 
168  bpos = 1;
169  memset(c->block + 1, 0, 15 * sizeof(*c->block));
170  for (l = 0; l < nc; l++) {
171  ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2);
172  if (ac == -1)
173  return AVERROR_INVALIDDATA;
174  if (ac == 0x1000)
175  ac = get_bits(gb, 12);
176  bpos += ac & 0xF;
177  if (bpos >= 16)
178  return AVERROR_INVALIDDATA;
179  val = sign_extend(ac >> 4, 8);
180  c->block[tscc2_zigzag[bpos++]] = val;
181  }
182  tscc2_idct4_put(c->block, q, dst + k * 4, stride);
183  }
184  dst += 4 * stride;
185  }
186  return 0;
187 }
188 
189 static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
190  const uint8_t *buf, int buf_size)
191 {
192  int i, mb_x, q, ret;
193  int off;
194 
195  init_get_bits(&c->gb, buf, buf_size * 8);
196 
197  for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
198  q = c->slice_quants[mb_x + c->mb_width * mb_y];
199 
200  if (q == 0 || q == 3) // skip block
201  continue;
202  for (i = 0; i < 3; i++) {
203  off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];
204  ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,
205  c->pic->data[i] + off, c->pic->linesize[i], i);
206  if (ret)
207  return ret;
208  }
209  }
210 
211  return 0;
212 }
213 
214 static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
215  int *got_frame, AVPacket *avpkt)
216 {
217  const uint8_t *buf = avpkt->data;
218  int buf_size = avpkt->size;
219  TSCC2Context *c = avctx->priv_data;
220  GetByteContext gb;
221  uint32_t frame_type, size;
222  int i, val, len, pos = 0;
223  int num_mb = c->mb_width * c->mb_height;
224  int ret;
225 
226  bytestream2_init(&gb, buf, buf_size);
227  frame_type = bytestream2_get_byte(&gb);
228  if (frame_type > 1) {
229  av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %d\n", frame_type);
230  return AVERROR_INVALIDDATA;
231  }
232 
233  if ((ret = ff_reget_buffer(avctx, c->pic)) < 0) {
234  return ret;
235  }
236 
237  if (frame_type == 0) {
238  *got_frame = 1;
239  if ((ret = av_frame_ref(data, c->pic)) < 0)
240  return ret;
241 
242  return buf_size;
243  }
244 
245  if (bytestream2_get_bytes_left(&gb) < 4) {
246  av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
247  return AVERROR_INVALIDDATA;
248  }
249 
250  c->quant[0] = bytestream2_get_byte(&gb);
251  c->quant[1] = bytestream2_get_byte(&gb);
252  if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
253  c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {
254  av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",
255  c->quant[0], c->quant[1]);
256  return AVERROR_INVALIDDATA;
257  }
258 
259  for (i = 0; i < 3; i++) {
260  c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
261  c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
262  }
263 
264  bytestream2_skip(&gb, 1);
265 
266  size = bytestream2_get_le32(&gb);
267  if (size > bytestream2_get_bytes_left(&gb)) {
268  av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");
269  return AVERROR_INVALIDDATA;
270  }
271 
272  for (i = 0; i < size; i++) {
273  val = bytestream2_get_byte(&gb);
274  len = val & 0x3F;
275  val >>= 6;
276  if (pos + len > num_mb) {
277  av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
278  return AVERROR_INVALIDDATA;
279  }
280  memset(c->slice_quants + pos, val, len);
281  pos += len;
282  }
283  if (pos < num_mb) {
284  av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",
285  pos, num_mb);
286  return AVERROR_INVALIDDATA;
287  }
288 
289  for (i = 0; i < c->mb_height; i++) {
290  size = bytestream2_peek_byte(&gb);
291  if (size & 1) {
292  size = bytestream2_get_byte(&gb) - 1;
293  } else {
294  size = bytestream2_get_le32(&gb) >> 1;
295  }
296  if (!size) {
297  int skip_row = 1, j, off = i * c->mb_width;
298  for (j = 0; j < c->mb_width; j++) {
299  if (c->slice_quants[off + j] == 1 ||
300  c->slice_quants[off + j] == 2) {
301  skip_row = 0;
302  break;
303  }
304  }
305  if (!skip_row) {
306  av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
307  return AVERROR_INVALIDDATA;
308  }
309  }
310  if (bytestream2_get_bytes_left(&gb) < size) {
311  av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%d/%d)\n",
312  size, bytestream2_get_bytes_left(&gb));
313  return AVERROR_INVALIDDATA;
314  }
315  ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
316  if (ret) {
317  av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
318  return ret;
319  }
320  bytestream2_skip(&gb, size);
321  }
322 
323  *got_frame = 1;
324  if ((ret = av_frame_ref(data, c->pic)) < 0)
325  return ret;
326 
327  /* always report that the buffer was completely consumed */
328  return buf_size;
329 }
330 
331 static av_cold int tscc2_decode_end(AVCodecContext *avctx)
332 {
333  TSCC2Context * const c = avctx->priv_data;
334 
335  av_frame_free(&c->pic);
336  av_freep(&c->slice_quants);
337  free_vlcs(c);
338 
339  return 0;
340 }
341 
342 static av_cold int tscc2_decode_init(AVCodecContext *avctx)
343 {
344  TSCC2Context * const c = avctx->priv_data;
345  int ret;
346 
347  c->avctx = avctx;
348 
349  avctx->pix_fmt = AV_PIX_FMT_YUV444P;
350 
351  if ((ret = init_vlcs(c)) < 0) {
352  av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
353  return ret;
354  }
355 
356  c->mb_width = FFALIGN(avctx->width, 16) >> 4;
357  c->mb_height = FFALIGN(avctx->height, 8) >> 3;
358  c->slice_quants = av_malloc(c->mb_width * c->mb_height);
359  if (!c->slice_quants) {
360  av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
361  free_vlcs(c);
362  return AVERROR(ENOMEM);
363  }
364 
365  c->pic = av_frame_alloc();
366  if (!c->pic) {
367  tscc2_decode_end(avctx);
368  return AVERROR(ENOMEM);
369  }
370 
371  return 0;
372 }
373 
374 AVCodec ff_tscc2_decoder = {
375  .name = "tscc2",
376  .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),
377  .type = AVMEDIA_TYPE_VIDEO,
378  .id = AV_CODEC_ID_TSCC2,
379  .priv_data_size = sizeof(TSCC2Context),
380  .init = tscc2_decode_init,
381  .close = tscc2_decode_end,
382  .decode = tscc2_decode_frame,
383  .capabilities = CODEC_CAP_DR1,
384 };
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