GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/tscc2.c Lines: 147 174 84.5 %
Date: 2021-01-20 23:14:43 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.
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 *
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 * 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
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 * Lesser General Public License for more details.
16
 *
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 * You should have received a copy of the GNU Lesser General Public
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 * 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;
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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];
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61
54
    vlc->table           = &vlc_buf[*offset];
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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,
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                             INIT_VLC_STATIC_OVERLONG | INIT_VLC_OUTPUT_LE, NULL);
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54
    *offset += vlc->table_size;
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54
}
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69
2
static av_cold void tscc2_init_vlcs(void)
70
{
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2
    const uint16_t *ac_vlc_syms = tscc2_ac_vlc_syms;
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2
    const uint8_t  *ac_vlc_lens = tscc2_ac_vlc_lens;
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2
    int i, offset = 0;
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75
2
    tscc2_init_vlc(&dc_vlc, &offset, DC_VLC_COUNT,
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                   tscc2_dc_vlc_lens, tscc2_dc_vlc_syms, 2);
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78
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);
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82
26
        tscc2_init_vlc(&ac_vlc[i], &offset, tscc2_ac_vlc_sizes[i],
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                       ac_vlc_lens, ac_vlc_syms, 2);
84
26
        ac_vlc_lens += tscc2_ac_vlc_sizes[i];
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26
        ac_vlc_syms += tscc2_ac_vlc_sizes[i];
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    }
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2
}
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#define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8)
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#define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
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    OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3));  \
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    OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1));  \
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    OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1));  \
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    OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3));  \
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#define COL_OP(a, b)  a = (b)
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#define ROW_OP(a, b)  a = ((b) + 0x20) >> 6
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441488
static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
100
{
101
    int i;
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    int tblk[4 * 4];
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    int t0, t1, t2, t3;
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2207440
    for (i = 0; i < 4; i++) {
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1765952
        t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
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1765952
        t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
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1765952
        t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
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1765952
        t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
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1765952
        DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
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              tblk[2 * 4 + i], tblk[3 * 4 + i],
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              t0, t1, t2, t3, COL_OP);
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    }
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2207440
    for (i = 0; i < 4; i++) {
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1765952
        DCT1D(dst[0], dst[1], dst[2], dst[3],
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              tblk[i * 4 + 0], tblk[i * 4 + 1],
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              tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
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1765952
        dst += stride;
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    }
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441488
}
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66141
static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
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                           uint8_t *dst, int stride, int plane)
124
{
125
66141
    GetBitContext *gb = &c->gb;
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    int prev_dc, dc, nc, ac, bpos, val;
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    int i, j, k, l;
128
129
66141
    if (get_bits1(gb)) {
130
10955
        if (get_bits1(gb)) {
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10954
            val = get_bits(gb, 8);
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98586
            for (i = 0; i < 8; i++, dst += stride)
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87632
                memset(dst, val, 16);
134
        } else {
135
1
            if (get_bits_left(gb) < 16 * 8 * 8)
136
                return AVERROR_INVALIDDATA;
137
9
            for (i = 0; i < 8; i++) {
138
136
                for (j = 0; j < 16; j++)
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128
                    dst[j] = get_bits(gb, 8);
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8
                dst += stride;
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            }
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        }
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10955
        return 0;
144
    }
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146
55186
    prev_dc = 0;
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165558
    for (j = 0; j < 2; j++) {
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551860
        for (k = 0; k < 4; k++) {
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441488
            if (!(j | k)) {
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55186
                dc = get_bits(gb, 8);
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            } else {
152
386302
                dc = get_vlc2(gb, dc_vlc.table, TSCC2_VLC_BITS, 2);
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386302
                if (dc == 0x100)
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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;
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160
441488
            nc = get_vlc2(gb, nc_vlc[vlc_set].table, TSCC2_VLC_BITS, 1);
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162
441488
            bpos = 1;
163
441488
            memset(c->block + 1, 0, 15 * sizeof(*c->block));
164
2082935
            for (l = 0; l < nc; l++) {
165
1641447
                ac = get_vlc2(gb, ac_vlc[vlc_set].table, TSCC2_VLC_BITS, 2);
166
1641447
                if (ac == 0x1000)
167
48321
                    ac = get_bits(gb, 12);
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1641447
                bpos += ac & 0xF;
169
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);
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        }
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
1084
    if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0)
188
        return ret;
189
190
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

33776
        if (q == 0 || q == 3) // skip block
194
11729
            continue;
195
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
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
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
48
    if (frame_type == 0) {
228
        // Skip duplicate frames
229
17
        return buf_size;
230
    }
231
232
31
    if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0) {
233
        return ret;
234
    }
235
236
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

31
    if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
244

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
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
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
3319
    for (i = 0; i < size; i++) {
264
3288
        val   = bytestream2_get_byte(&gb);
265
3288
        len   = val & 0x3F;
266
3288
        val >>= 6;
267
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
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
1115
    for (i = 0; i < c->mb_height; i++) {
281
1085
        size = bytestream2_peek_byte(&gb);
282
1085
        if (size & 1) {
283
103
            size = bytestream2_get_byte(&gb) - 1;
284
        } else {
285
982
            size = bytestream2_get_le32(&gb) >> 1;
286
        }
287
1085
        if (!size) {
288
103
            int skip_row = 1, j, off = i * c->mb_width;
289
5871
            for (j = 0; j < c->mb_width; j++) {
290
5768
                if (c->slice_quants[off + j] == 1 ||
291
5768
                    c->slice_quants[off + j] == 2) {
292
                    skip_row = 0;
293
                    break;
294
                }
295
            }
296
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
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
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
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
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
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
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
};