FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/tscc2.c
Date: 2021-09-16 08:47:15
Exec Total Coverage
Lines: 147 174 84.5%
Branches: 72 94 76.6%

Line Branch Exec Source
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 "get_bits.h"
35 #include "internal.h"
36 #include "mathops.h"
37 #include "tscc2data.h"
38
39 #define TSCC2_VLC_BITS 9
40
41 typedef struct TSCC2Context {
42 AVCodecContext *avctx;
43 AVFrame *pic;
44 int mb_width, mb_height;
45 uint8_t *slice_quants;
46 int quant[2];
47 int q[2][3];
48 GetBitContext gb;
49
50 int block[16];
51 } TSCC2Context;
52
53 static VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
54
55 54 static av_cold void tscc2_init_vlc(VLC *vlc, int *offset, int nb_codes,
56 const uint8_t *lens, const void *syms,
57 int sym_length)
58 {
59 static VLC_TYPE vlc_buf[15442][2];
60
61 54 vlc->table = &vlc_buf[*offset];
62 54 vlc->table_allocated = FF_ARRAY_ELEMS(vlc_buf) - *offset;
63 54 ff_init_vlc_from_lengths(vlc, TSCC2_VLC_BITS, nb_codes,
64 lens, 1, syms, sym_length, sym_length, 0,
65 INIT_VLC_STATIC_OVERLONG | INIT_VLC_OUTPUT_LE, NULL);
66 54 *offset += vlc->table_size;
67 54 }
68
69 2 static av_cold void tscc2_init_vlcs(void)
70 {
71 2 const uint16_t *ac_vlc_syms = tscc2_ac_vlc_syms;
72 2 const uint8_t *ac_vlc_lens = tscc2_ac_vlc_lens;
73 2 int i, offset = 0;
74
75 2 tscc2_init_vlc(&dc_vlc, &offset, DC_VLC_COUNT,
76 tscc2_dc_vlc_lens, tscc2_dc_vlc_syms, 2);
77
78
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28 for (i = 0; i < NUM_VLC_SETS; i++) {
79 26 tscc2_init_vlc(&nc_vlc[i], &offset, 16,
80 26 tscc2_nc_vlc_lens[i], tscc2_nc_vlc_syms[i], 1);
81
82 26 tscc2_init_vlc(&ac_vlc[i], &offset, tscc2_ac_vlc_sizes[i],
83 ac_vlc_lens, ac_vlc_syms, 2);
84 26 ac_vlc_lens += tscc2_ac_vlc_sizes[i];
85 26 ac_vlc_syms += tscc2_ac_vlc_sizes[i];
86 }
87 2 }
88
89 #define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8)
90 #define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
91 OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3)); \
92 OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1)); \
93 OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1)); \
94 OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3)); \
95
96 #define COL_OP(a, b) a = (b)
97 #define ROW_OP(a, b) a = ((b) + 0x20) >> 6
98
99 441488 static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
100 {
101 int i;
102 int tblk[4 * 4];
103 int t0, t1, t2, t3;
104
105
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2207440 for (i = 0; i < 4; i++) {
106 1765952 t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
107 1765952 t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
108 1765952 t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
109 1765952 t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
110 1765952 DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
111 tblk[2 * 4 + i], tblk[3 * 4 + i],
112 t0, t1, t2, t3, COL_OP);
113 }
114
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2207440 for (i = 0; i < 4; i++) {
115 1765952 DCT1D(dst[0], dst[1], dst[2], dst[3],
116 tblk[i * 4 + 0], tblk[i * 4 + 1],
117 tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
118 1765952 dst += stride;
119 }
120 441488 }
121
122 66141 static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
123 uint8_t *dst, int stride, int plane)
124 {
125 66141 GetBitContext *gb = &c->gb;
126 int prev_dc, dc, nc, ac, bpos, val;
127 int i, j, k, l;
128
129
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66141 if (get_bits1(gb)) {
130
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10955 if (get_bits1(gb)) {
131 10954 val = get_bits(gb, 8);
132
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98586 for (i = 0; i < 8; i++, dst += stride)
133 87632 memset(dst, val, 16);
134 } else {
135
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1 if (get_bits_left(gb) < 16 * 8 * 8)
136 return AVERROR_INVALIDDATA;
137
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9 for (i = 0; i < 8; i++) {
138
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136 for (j = 0; j < 16; j++)
139 128 dst[j] = get_bits(gb, 8);
140 8 dst += stride;
141 }
142 }
143 10955 return 0;
144 }
145
146 55186 prev_dc = 0;
147
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165558 for (j = 0; j < 2; j++) {
148
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551860 for (k = 0; k < 4; k++) {
149
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441488 if (!(j | k)) {
150 55186 dc = get_bits(gb, 8);
151 } else {
152 386302 dc = get_vlc2(gb, dc_vlc.table, TSCC2_VLC_BITS, 2);
153
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386302 if (dc == 0x100)
154 22622 dc = get_bits(gb, 8);
155 }
156 441488 dc = (dc + prev_dc) & 0xFF;
157 441488 prev_dc = dc;
158 441488 c->block[0] = dc;
159
160 441488 nc = get_vlc2(gb, nc_vlc[vlc_set].table, TSCC2_VLC_BITS, 1);
161
162 441488 bpos = 1;
163 441488 memset(c->block + 1, 0, 15 * sizeof(*c->block));
164
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2082935 for (l = 0; l < nc; l++) {
165 1641447 ac = get_vlc2(gb, ac_vlc[vlc_set].table, TSCC2_VLC_BITS, 2);
166
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1641447 if (ac == 0x1000)
167 48321 ac = get_bits(gb, 12);
168 1641447 bpos += ac & 0xF;
169
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1641447 if (bpos >= 16)
170 return AVERROR_INVALIDDATA;
171 1641447 val = sign_extend(ac >> 4, 8);
172 1641447 c->block[ff_zigzag_scan[bpos++]] = val;
173 }
174 441488 tscc2_idct4_put(c->block, q, dst + k * 4, stride);
175 }
176 110372 dst += 4 * stride;
177 }
178 55186 return 0;
179 }
180
181 1084 static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
182 const uint8_t *buf, int buf_size)
183 {
184 int i, mb_x, q, ret;
185 int off;
186
187
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1084 if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0)
188 return ret;
189
190
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34860 for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
191 33776 q = c->slice_quants[mb_x + c->mb_width * mb_y];
192
193
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33776 if (q == 0 || q == 3) // skip block
194 11729 continue;
195
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88188 for (i = 0; i < 3; i++) {
196 66141 off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];
197 66141 ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,
198 66141 c->pic->data[i] + off, c->pic->linesize[i], i);
199
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66141 if (ret)
200 return ret;
201 }
202 }
203
204 1084 return 0;
205 }
206
207 48 static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
208 int *got_frame, AVPacket *avpkt)
209 {
210 48 const uint8_t *buf = avpkt->data;
211 48 int buf_size = avpkt->size;
212 48 TSCC2Context *c = avctx->priv_data;
213 GetByteContext gb;
214 uint32_t frame_type, size;
215 48 int i, val, len, pos = 0;
216 48 int num_mb = c->mb_width * c->mb_height;
217 int ret;
218
219 48 bytestream2_init(&gb, buf, buf_size);
220 48 frame_type = bytestream2_get_byte(&gb);
221
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48 if (frame_type > 1) {
222 av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n",
223 frame_type);
224 return AVERROR_INVALIDDATA;
225 }
226
227
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48 if (frame_type == 0) {
228 // Skip duplicate frames
229 17 return buf_size;
230 }
231
232
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31 if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0) {
233 return ret;
234 }
235
236
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31 if (bytestream2_get_bytes_left(&gb) < 4) {
237 av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
238 return AVERROR_INVALIDDATA;
239 }
240
241 31 c->quant[0] = bytestream2_get_byte(&gb);
242 31 c->quant[1] = bytestream2_get_byte(&gb);
243
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31 if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
244
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31 c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {
245 av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",
246 c->quant[0], c->quant[1]);
247 return AVERROR_INVALIDDATA;
248 }
249
250
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124 for (i = 0; i < 3; i++) {
251 93 c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
252 93 c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
253 }
254
255 31 bytestream2_skip(&gb, 1);
256
257 31 size = bytestream2_get_le32(&gb);
258
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31 if (size > bytestream2_get_bytes_left(&gb)) {
259 av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");
260 return AVERROR_INVALIDDATA;
261 }
262
263
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3319 for (i = 0; i < size; i++) {
264 3288 val = bytestream2_get_byte(&gb);
265 3288 len = val & 0x3F;
266 3288 val >>= 6;
267
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3288 if (pos + len > num_mb) {
268 av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
269 return AVERROR_INVALIDDATA;
270 }
271 3288 memset(c->slice_quants + pos, val, len);
272 3288 pos += len;
273 }
274
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31 if (pos < num_mb) {
275 av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",
276 pos, num_mb);
277 return AVERROR_INVALIDDATA;
278 }
279
280
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1115 for (i = 0; i < c->mb_height; i++) {
281 1085 size = bytestream2_peek_byte(&gb);
282
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1085 if (size & 1) {
283 103 size = bytestream2_get_byte(&gb) - 1;
284 } else {
285 982 size = bytestream2_get_le32(&gb) >> 1;
286 }
287
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1085 if (!size) {
288 103 int skip_row = 1, j, off = i * c->mb_width;
289
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5871 for (j = 0; j < c->mb_width; j++) {
290
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5768 if (c->slice_quants[off + j] == 1 ||
291
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5768 c->slice_quants[off + j] == 2) {
292 skip_row = 0;
293 break;
294 }
295 }
296
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103 if (!skip_row) {
297 av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
298 return AVERROR_INVALIDDATA;
299 }
300 }
301
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1085 if (bytestream2_get_bytes_left(&gb) < size) {
302 1 av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n",
303 size, bytestream2_get_bytes_left(&gb));
304 1 return AVERROR_INVALIDDATA;
305 }
306 1084 ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
307
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1084 if (ret) {
308 av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
309 return ret;
310 }
311 1084 bytestream2_skip(&gb, size);
312 }
313
314 30 *got_frame = 1;
315
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30 if ((ret = av_frame_ref(data, c->pic)) < 0)
316 return ret;
317
318 /* always report that the buffer was completely consumed */
319 30 return buf_size;
320 }
321
322 4 static av_cold int tscc2_decode_end(AVCodecContext *avctx)
323 {
324 4 TSCC2Context * const c = avctx->priv_data;
325
326 4 av_frame_free(&c->pic);
327 4 av_freep(&c->slice_quants);
328
329 4 return 0;
330 }
331
332 4 static av_cold int tscc2_decode_init(AVCodecContext *avctx)
333 {
334 4 TSCC2Context * const c = avctx->priv_data;
335 static AVOnce init_static_once = AV_ONCE_INIT;
336
337 4 c->avctx = avctx;
338
339 4 avctx->pix_fmt = AV_PIX_FMT_YUV444P;
340
341 4 c->mb_width = FFALIGN(avctx->width, 16) >> 4;
342 4 c->mb_height = FFALIGN(avctx->height, 8) >> 3;
343 4 c->slice_quants = av_malloc(c->mb_width * c->mb_height);
344
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4 if (!c->slice_quants) {
345 av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
346 return AVERROR(ENOMEM);
347 }
348
349 4 c->pic = av_frame_alloc();
350
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4 if (!c->pic)
351 return AVERROR(ENOMEM);
352
353 4 ff_thread_once(&init_static_once, tscc2_init_vlcs);
354
355 4 return 0;
356 }
357
358 const AVCodec ff_tscc2_decoder = {
359 .name = "tscc2",
360 .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),
361 .type = AVMEDIA_TYPE_VIDEO,
362 .id = AV_CODEC_ID_TSCC2,
363 .priv_data_size = sizeof(TSCC2Context),
364 .init = tscc2_decode_init,
365 .close = tscc2_decode_end,
366 .decode = tscc2_decode_frame,
367 .capabilities = AV_CODEC_CAP_DR1,
368 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
369 };
370