GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/mpeg12.c Lines: 134 143 93.7 %
Date: 2021-04-20 04:37:23 Branches: 70 78 89.7 %

Line Branch Exec Source
1
/*
2
 * MPEG-1/2 decoder
3
 * Copyright (c) 2000, 2001 Fabrice Bellard
4
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5
 *
6
 * This file is part of FFmpeg.
7
 *
8
 * FFmpeg is free software; you can redistribute it and/or
9
 * modify it under the terms of the GNU Lesser General Public
10
 * License as published by the Free Software Foundation; either
11
 * version 2.1 of the License, or (at your option) any later version.
12
 *
13
 * FFmpeg is distributed in the hope that it will be useful,
14
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16
 * Lesser General Public License for more details.
17
 *
18
 * You should have received a copy of the GNU Lesser General Public
19
 * License along with FFmpeg; if not, write to the Free Software
20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21
 */
22
23
/**
24
 * @file
25
 * MPEG-1/2 decoder
26
 */
27
28
#define UNCHECKED_BITSTREAM_READER 1
29
30
#include "libavutil/attributes.h"
31
#include "libavutil/avassert.h"
32
#include "libavutil/timecode.h"
33
#include "libavutil/thread.h"
34
35
#include "internal.h"
36
#include "avcodec.h"
37
#include "mpegvideo.h"
38
#include "error_resilience.h"
39
#include "mpeg12.h"
40
#include "mpeg12data.h"
41
#include "mpegvideodata.h"
42
#include "bytestream.h"
43
#include "thread.h"
44
45
static const uint8_t table_mb_ptype[7][2] = {
46
    { 3, 5 }, // 0x01 MB_INTRA
47
    { 1, 2 }, // 0x02 MB_PAT
48
    { 1, 3 }, // 0x08 MB_FOR
49
    { 1, 1 }, // 0x0A MB_FOR|MB_PAT
50
    { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
51
    { 1, 5 }, // 0x12 MB_QUANT|MB_PAT
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    { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
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};
54
55
static const uint8_t table_mb_btype[11][2] = {
56
    { 3, 5 }, // 0x01 MB_INTRA
57
    { 2, 3 }, // 0x04 MB_BACK
58
    { 3, 3 }, // 0x06 MB_BACK|MB_PAT
59
    { 2, 4 }, // 0x08 MB_FOR
60
    { 3, 4 }, // 0x0A MB_FOR|MB_PAT
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    { 2, 2 }, // 0x0C MB_FOR|MB_BACK
62
    { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT
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    { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
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    { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT
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    { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
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    { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
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};
68
69
242
av_cold void ff_init_2d_vlc_rl(RLTable *rl, unsigned static_size, int flags)
70
{
71
    int i;
72
242
    VLC_TYPE table[680][2] = {{0}};
73
242
    VLC vlc = { .table = table, .table_allocated = static_size };
74
242
    av_assert0(static_size <= FF_ARRAY_ELEMS(table));
75
242
    init_vlc(&vlc, TEX_VLC_BITS, rl->n + 2, &rl->table_vlc[0][1], 4, 2, &rl->table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | flags);
76
77
164070
    for (i = 0; i < vlc.table_size; i++) {
78
163828
        int code = vlc.table[i][0];
79
163828
        int len  = vlc.table[i][1];
80
        int level, run;
81
82
163828
        if (len == 0) { // illegal code
83
5072
            run   = 65;
84
5072
            level = MAX_LEVEL;
85
158756
        } else if (len<0) { //more bits needed
86
1570
            run   = 0;
87
1570
            level = code;
88
        } else {
89
157186
            if (code == rl->n) { //esc
90
1936
                run   = 65;
91
1936
                level = 0;
92
155250
            } else if (code == rl->n+1) { //eob
93
19264
                run   = 0;
94
19264
                level = 127;
95
            } else {
96
135986
                run   = rl->table_run  [code] + 1;
97
135986
                level = rl->table_level[code];
98
            }
99
        }
100
163828
        rl->rl_vlc[0][i].len   = len;
101
163828
        rl->rl_vlc[0][i].level = level;
102
163828
        rl->rl_vlc[0][i].run   = run;
103
    }
104
242
}
105
106
308
av_cold void ff_mpeg12_common_init(MpegEncContext *s)
107
{
108
109
308
    s->y_dc_scale_table =
110
308
    s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
111
112
308
}
113
114
399158
void ff_mpeg1_clean_buffers(MpegEncContext *s)
115
{
116
399158
    s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
117
399158
    s->last_dc[1] = s->last_dc[0];
118
399158
    s->last_dc[2] = s->last_dc[0];
119
399158
    memset(s->last_mv, 0, sizeof(s->last_mv));
120
399158
}
121
122
123
/******************************************/
124
/* decoding */
125
126
VLC ff_mv_vlc;
127
128
VLC ff_dc_lum_vlc;
129
VLC ff_dc_chroma_vlc;
130
131
VLC ff_mbincr_vlc;
132
VLC ff_mb_ptype_vlc;
133
VLC ff_mb_btype_vlc;
134
VLC ff_mb_pat_vlc;
135
136
120
static av_cold void mpeg12_init_vlcs(void)
137
{
138
120
    INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
139
                    ff_mpeg12_vlc_dc_lum_bits, 1, 1,
140
                    ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
141
120
    INIT_VLC_STATIC(&ff_dc_chroma_vlc,  DC_VLC_BITS, 12,
142
                    ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
143
                    ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
144
120
    INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
145
                    &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
146
                    &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 266);
147
120
    INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
148
                    &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
149
                    &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
150
120
    INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
151
                    &ff_mpeg12_mbPatTable[0][1], 2, 1,
152
                    &ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
153
154
120
    INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
155
                    &table_mb_ptype[0][1], 2, 1,
156
                    &table_mb_ptype[0][0], 2, 1, 64);
157
120
    INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
158
                    &table_mb_btype[0][1], 2, 1,
159
                    &table_mb_btype[0][0], 2, 1, 64);
160
161
120
    INIT_2D_VLC_RL(ff_rl_mpeg1, 680, 0);
162
120
    INIT_2D_VLC_RL(ff_rl_mpeg2, 674, 0);
163
120
}
164
165
273
av_cold void ff_mpeg12_init_vlcs(void)
166
{
167
    static AVOnce init_static_once = AV_ONCE_INIT;
168
273
    ff_thread_once(&init_static_once, mpeg12_init_vlcs);
169
273
}
170
171
/**
172
 * Find the end of the current frame in the bitstream.
173
 * @return the position of the first byte of the next frame, or -1
174
 */
175
45008
int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
176
{
177
    int i;
178
45008
    uint32_t state = pc->state;
179
180
    /* EOF considered as end of frame */
181
45008
    if (buf_size == 0)
182
312
        return 0;
183
184
/*
185
 0  frame start         -> 1/4
186
 1  first_SEQEXT        -> 0/2
187
 2  first field start   -> 3/0
188
 3  second_SEQEXT       -> 2/0
189
 4  searching end
190
*/
191
192
250313
    for (i = 0; i < buf_size; i++) {
193
        av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
194
211213
        if (pc->frame_start_found & 1) {
195

20856
            if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
196
2094
                pc->frame_start_found--;
197
18762
            else if (state == EXT_START_CODE + 2) {
198
6254
                if ((buf[i] & 3) == 3)
199
3899
                    pc->frame_start_found = 0;
200
                else
201
2355
                    pc->frame_start_found = (pc->frame_start_found + 1) & 3;
202
            }
203
20856
            state++;
204
        } else {
205
190357
            i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
206

190357
            if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
207
6028
                i++;
208
6028
                pc->frame_start_found = 4;
209
            }
210
190357
            if (state == SEQ_END_CODE) {
211
8
                pc->frame_start_found = 0;
212
8
                pc->state=-1;
213
8
                return i+1;
214
            }
215

190349
            if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
216
                pc->frame_start_found = 0;
217

190349
            if (pc->frame_start_found  < 4 && state == EXT_START_CODE)
218
8348
                pc->frame_start_found++;
219

190349
            if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
220

115356
                if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
221
5588
                    pc->frame_start_found = 0;
222
5588
                    pc->state             = -1;
223
5588
                    return i - 3;
224
                }
225
            }
226

184761
            if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
227
5989
                ff_fetch_timestamp(s, i - 3, 1, i > 3);
228
            }
229
        }
230
    }
231
39100
    pc->state = state;
232
39100
    return END_NOT_FOUND;
233
}
234
235
#define MAX_INDEX (64 - 1)
236
237
176526
int ff_mpeg1_decode_block_intra(GetBitContext *gb,
238
                                const uint16_t *quant_matrix,
239
                                uint8_t *const scantable, int last_dc[3],
240
                                int16_t *block, int index, int qscale)
241
{
242
176526
    int dc, diff, i = 0, component;
243
176526
    RLTable *rl = &ff_rl_mpeg1;
244
245
    /* DC coefficient */
246
176526
    component = index <= 3 ? 0 : index - 4 + 1;
247
248
176526
    diff = decode_dc(gb, component);
249
176526
    if (diff >= 0xffff)
250
        return AVERROR_INVALIDDATA;
251
252
176526
    dc  = last_dc[component];
253
176526
    dc += diff;
254
176526
    last_dc[component] = dc;
255
256
176526
    block[0] = dc * quant_matrix[0];
257
258
    {
259
176526
        OPEN_READER(re, gb);
260
176526
        UPDATE_CACHE(re, gb);
261
176526
        if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
262
36372
            goto end;
263
264
        /* now quantify & encode AC coefficients */
265
1334388
        while (1) {
266
            int level, run, j;
267
268
1474542
            GET_RL_VLC(level, run, re, gb, rl->rl_vlc[0],
269
                       TEX_VLC_BITS, 2, 0);
270
271
1474542
            if (level != 0) {
272
1469278
                i += run;
273
1469278
                if (i > MAX_INDEX)
274
                    break;
275
276
1469278
                j = scantable[i];
277
1469278
                level = (level * qscale * quant_matrix[j]) >> 4;
278
1469278
                level = (level - 1) | 1;
279
1469278
                level = (level ^ SHOW_SBITS(re, gb, 1)) -
280
1469278
                        SHOW_SBITS(re, gb, 1);
281
1469278
                SKIP_BITS(re, gb, 1);
282
            } else {
283
                /* escape */
284
5264
                run = SHOW_UBITS(re, gb, 6) + 1;
285
5264
                LAST_SKIP_BITS(re, gb, 6);
286
5264
                UPDATE_CACHE(re, gb);
287
5264
                level = SHOW_SBITS(re, gb, 8);
288
5264
                SKIP_BITS(re, gb, 8);
289
290
5264
                if (level == -128) {
291
                    level = SHOW_UBITS(re, gb, 8) - 256;
292
                    SKIP_BITS(re, gb, 8);
293
5264
                } else if (level == 0) {
294
                    level = SHOW_UBITS(re, gb, 8);
295
                    SKIP_BITS(re, gb, 8);
296
                }
297
298
5264
                i += run;
299
5264
                if (i > MAX_INDEX)
300
                    break;
301
302
5264
                j = scantable[i];
303
5264
                if (level < 0) {
304
2967
                    level = -level;
305
2967
                    level = (level * qscale * quant_matrix[j]) >> 4;
306
2967
                    level = (level - 1) | 1;
307
2967
                    level = -level;
308
                } else {
309
2297
                    level = (level * qscale * quant_matrix[j]) >> 4;
310
2297
                    level = (level - 1) | 1;
311
                }
312
            }
313
314
1474542
            block[j] = level;
315
1474542
            if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
316
140154
               break;
317
318
1334388
            UPDATE_CACHE(re, gb);
319
        }
320
176526
end:
321
176526
        LAST_SKIP_BITS(re, gb, 2);
322
176526
        CLOSE_READER(re, gb);
323
    }
324
325
176526
    if (i > MAX_INDEX)
326
        i = AVERROR_INVALIDDATA;
327
328
176526
    return i;
329
}