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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 #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 
36 typedef struct TSCC2Context {
41  int quant[2];
42  int q[2][3];
44 
46  int block[16];
47 } TSCC2Context;
48 
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 
61 {
62  int i, ret;
63 
65  tscc2_dc_vlc_bits, 1, 1,
66  tscc2_dc_vlc_codes, 2, 2,
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,
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 
103 static 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 
126 static 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 
191 static 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 
217 static 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 
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 
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;
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 
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),
387  .capabilities = CODEC_CAP_DR1,
388 };