GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/tscc2.c Lines: 153 192 79.7 %
Date: 2020-08-14 10:39:37 Branches: 81 110 73.6 %

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
#define BITSTREAM_READER_LE
30
#include "avcodec.h"
31
#include "bytestream.h"
32
#include "get_bits.h"
33
#include "internal.h"
34
#include "mathops.h"
35
#include "tscc2data.h"
36
37
typedef struct TSCC2Context {
38
    AVCodecContext *avctx;
39
    AVFrame       *pic;
40
    int            mb_width, mb_height;
41
    uint8_t        *slice_quants;
42
    int            quant[2];
43
    int            q[2][3];
44
    GetBitContext  gb;
45
46
    VLC            dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
47
    int            block[16];
48
} TSCC2Context;
49
50
4
static av_cold void free_vlcs(TSCC2Context *c)
51
{
52
    int i;
53
54
4
    ff_free_vlc(&c->dc_vlc);
55
56
    for (i = 0; i < NUM_VLC_SETS; i++) {
56
52
        ff_free_vlc(c->nc_vlc + i);
57
52
        ff_free_vlc(c->ac_vlc + i);
58
    }
59
4
}
60
61
4
static av_cold int init_vlcs(TSCC2Context *c)
62
{
63
    int i, ret;
64
65
4
    ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT,
66
                             tscc2_dc_vlc_bits,  1, 1,
67
                             tscc2_dc_vlc_codes, 2, 2,
68
                             tscc2_dc_vlc_syms,  2, 2, INIT_VLC_LE);
69
4
    if (ret)
70
        return ret;
71
72
56
    for (i = 0; i < NUM_VLC_SETS; i++) {
73
52
        ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16,
74
52
                                 tscc2_nc_vlc_bits[i],  1, 1,
75
52
                                 tscc2_nc_vlc_codes[i], 2, 2,
76
                                 tscc2_nc_vlc_syms,     1, 1, INIT_VLC_LE);
77
52
        if (ret) {
78
            free_vlcs(c);
79
            return ret;
80
        }
81
52
        ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i],
82
52
                                 tscc2_ac_vlc_bits[i],  1, 1,
83
52
                                 tscc2_ac_vlc_codes[i], 2, 2,
84
52
                                 tscc2_ac_vlc_syms[i],  2, 2, INIT_VLC_LE);
85
52
        if (ret) {
86
            free_vlcs(c);
87
            return ret;
88
        }
89
    }
90
91
4
    return 0;
92
}
93
94
#define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8)
95
#define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
96
    OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3));  \
97
    OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1));  \
98
    OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1));  \
99
    OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3));  \
100
101
#define COL_OP(a, b)  a = (b)
102
#define ROW_OP(a, b)  a = ((b) + 0x20) >> 6
103
104
441488
static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
105
{
106
    int i;
107
    int tblk[4 * 4];
108
    int t0, t1, t2, t3;
109
110
2207440
    for (i = 0; i < 4; i++) {
111
1765952
        t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
112
1765952
        t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
113
1765952
        t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
114
1765952
        t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
115
1765952
        DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
116
              tblk[2 * 4 + i], tblk[3 * 4 + i],
117
              t0, t1, t2, t3, COL_OP);
118
    }
119
2207440
    for (i = 0; i < 4; i++) {
120
1765952
        DCT1D(dst[0], dst[1], dst[2], dst[3],
121
              tblk[i * 4 + 0], tblk[i * 4 + 1],
122
              tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
123
1765952
        dst += stride;
124
    }
125
441488
}
126
127
66141
static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
128
                           uint8_t *dst, int stride, int plane)
129
{
130
66141
    GetBitContext *gb = &c->gb;
131
    int prev_dc, dc, nc, ac, bpos, val;
132
    int i, j, k, l;
133
134
66141
    if (get_bits1(gb)) {
135
10955
        if (get_bits1(gb)) {
136
10954
            val = get_bits(gb, 8);
137
98586
            for (i = 0; i < 8; i++, dst += stride)
138
87632
                memset(dst, val, 16);
139
        } else {
140
1
            if (get_bits_left(gb) < 16 * 8 * 8)
141
                return AVERROR_INVALIDDATA;
142
9
            for (i = 0; i < 8; i++) {
143
136
                for (j = 0; j < 16; j++)
144
128
                    dst[j] = get_bits(gb, 8);
145
8
                dst += stride;
146
            }
147
        }
148
10955
        return 0;
149
    }
150
151
55186
    prev_dc = 0;
152
165558
    for (j = 0; j < 2; j++) {
153
551860
        for (k = 0; k < 4; k++) {
154
441488
            if (!(j | k)) {
155
55186
                dc = get_bits(gb, 8);
156
            } else {
157
386302
                dc = get_vlc2(gb, c->dc_vlc.table, 9, 2);
158
386302
                if (dc == -1)
159
                    return AVERROR_INVALIDDATA;
160
386302
                if (dc == 0x100)
161
22622
                    dc = get_bits(gb, 8);
162
            }
163
441488
            dc          = (dc + prev_dc) & 0xFF;
164
441488
            prev_dc     = dc;
165
441488
            c->block[0] = dc;
166
167
441488
            nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1);
168
441488
            if (nc == -1)
169
                return AVERROR_INVALIDDATA;
170
171
441488
            bpos = 1;
172
441488
            memset(c->block + 1, 0, 15 * sizeof(*c->block));
173
2082935
            for (l = 0; l < nc; l++) {
174
1641447
                ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2);
175
1641447
                if (ac == -1)
176
                    return AVERROR_INVALIDDATA;
177
1641447
                if (ac == 0x1000)
178
48321
                    ac = get_bits(gb, 12);
179
1641447
                bpos += ac & 0xF;
180
1641447
                if (bpos >= 16)
181
                    return AVERROR_INVALIDDATA;
182
1641447
                val = sign_extend(ac >> 4, 8);
183
1641447
                c->block[ff_zigzag_scan[bpos++]] = val;
184
            }
185
441488
            tscc2_idct4_put(c->block, q, dst + k * 4, stride);
186
        }
187
110372
        dst += 4 * stride;
188
    }
189
55186
    return 0;
190
}
191
192
1084
static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
193
                              const uint8_t *buf, int buf_size)
194
{
195
    int i, mb_x, q, ret;
196
    int off;
197
198
1084
    if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0)
199
        return ret;
200
201
34860
    for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
202
33776
        q = c->slice_quants[mb_x + c->mb_width * mb_y];
203
204

33776
        if (q == 0 || q == 3) // skip block
205
11729
            continue;
206
88188
        for (i = 0; i < 3; i++) {
207
66141
            off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];
208
66141
            ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,
209
66141
                                  c->pic->data[i] + off, c->pic->linesize[i], i);
210
66141
            if (ret)
211
                return ret;
212
        }
213
    }
214
215
1084
    return 0;
216
}
217
218
48
static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
219
                              int *got_frame, AVPacket *avpkt)
220
{
221
48
    const uint8_t *buf = avpkt->data;
222
48
    int buf_size = avpkt->size;
223
48
    TSCC2Context *c = avctx->priv_data;
224
    GetByteContext gb;
225
    uint32_t frame_type, size;
226
48
    int i, val, len, pos = 0;
227
48
    int num_mb = c->mb_width * c->mb_height;
228
    int ret;
229
230
48
    bytestream2_init(&gb, buf, buf_size);
231
48
    frame_type = bytestream2_get_byte(&gb);
232
48
    if (frame_type > 1) {
233
        av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n",
234
               frame_type);
235
        return AVERROR_INVALIDDATA;
236
    }
237
238
48
    if (frame_type == 0) {
239
        // Skip duplicate frames
240
17
        return buf_size;
241
    }
242
243
31
    if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0) {
244
        return ret;
245
    }
246
247
31
    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
31
    c->quant[0] = bytestream2_get_byte(&gb);
253
31
    c->quant[1] = bytestream2_get_byte(&gb);
254

31
    if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
255

31
        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
124
    for (i = 0; i < 3; i++) {
262
93
        c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
263
93
        c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
264
    }
265
266
31
    bytestream2_skip(&gb, 1);
267
268
31
    size = bytestream2_get_le32(&gb);
269
31
    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
3319
    for (i = 0; i < size; i++) {
275
3288
        val   = bytestream2_get_byte(&gb);
276
3288
        len   = val & 0x3F;
277
3288
        val >>= 6;
278
3288
        if (pos + len > num_mb) {
279
            av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
280
            return AVERROR_INVALIDDATA;
281
        }
282
3288
        memset(c->slice_quants + pos, val, len);
283
3288
        pos += len;
284
    }
285
31
    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
1115
    for (i = 0; i < c->mb_height; i++) {
292
1085
        size = bytestream2_peek_byte(&gb);
293
1085
        if (size & 1) {
294
103
            size = bytestream2_get_byte(&gb) - 1;
295
        } else {
296
982
            size = bytestream2_get_le32(&gb) >> 1;
297
        }
298
1085
        if (!size) {
299
103
            int skip_row = 1, j, off = i * c->mb_width;
300
5871
            for (j = 0; j < c->mb_width; j++) {
301
5768
                if (c->slice_quants[off + j] == 1 ||
302
5768
                    c->slice_quants[off + j] == 2) {
303
                    skip_row = 0;
304
                    break;
305
                }
306
            }
307
103
            if (!skip_row) {
308
                av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
309
                return AVERROR_INVALIDDATA;
310
            }
311
        }
312
1085
        if (bytestream2_get_bytes_left(&gb) < size) {
313
1
            av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n",
314
                   size, bytestream2_get_bytes_left(&gb));
315
1
            return AVERROR_INVALIDDATA;
316
        }
317
1084
        ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
318
1084
        if (ret) {
319
            av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
320
            return ret;
321
        }
322
1084
        bytestream2_skip(&gb, size);
323
    }
324
325
30
    *got_frame      = 1;
326
30
    if ((ret = av_frame_ref(data, c->pic)) < 0)
327
        return ret;
328
329
    /* always report that the buffer was completely consumed */
330
30
    return buf_size;
331
}
332
333
4
static av_cold int tscc2_decode_end(AVCodecContext *avctx)
334
{
335
4
    TSCC2Context * const c = avctx->priv_data;
336
337
4
    av_frame_free(&c->pic);
338
4
    av_freep(&c->slice_quants);
339
4
    free_vlcs(c);
340
341
4
    return 0;
342
}
343
344
4
static av_cold int tscc2_decode_init(AVCodecContext *avctx)
345
{
346
4
    TSCC2Context * const c = avctx->priv_data;
347
    int ret;
348
349
4
    c->avctx = avctx;
350
351
4
    avctx->pix_fmt = AV_PIX_FMT_YUV444P;
352
353
4
    if ((ret = init_vlcs(c)) < 0) {
354
        av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
355
        return ret;
356
    }
357
358
4
    c->mb_width     = FFALIGN(avctx->width,  16) >> 4;
359
4
    c->mb_height    = FFALIGN(avctx->height,  8) >> 3;
360
4
    c->slice_quants = av_malloc(c->mb_width * c->mb_height);
361
4
    if (!c->slice_quants) {
362
        av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
363
        free_vlcs(c);
364
        return AVERROR(ENOMEM);
365
    }
366
367
4
    c->pic = av_frame_alloc();
368
4
    if (!c->pic) {
369
        tscc2_decode_end(avctx);
370
        return AVERROR(ENOMEM);
371
    }
372
373
4
    return 0;
374
}
375
376
AVCodec ff_tscc2_decoder = {
377
    .name           = "tscc2",
378
    .long_name      = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),
379
    .type           = AVMEDIA_TYPE_VIDEO,
380
    .id             = AV_CODEC_ID_TSCC2,
381
    .priv_data_size = sizeof(TSCC2Context),
382
    .init           = tscc2_decode_init,
383
    .close          = tscc2_decode_end,
384
    .decode         = tscc2_decode_frame,
385
    .capabilities   = AV_CODEC_CAP_DR1,
386
};