GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/dstdec.c Lines: 122 173 70.5 %
Date: 2021-01-21 21:11:50 Branches: 52 96 54.2 %

Line Branch Exec Source
1
/*
2
 * Direct Stream Transfer (DST) decoder
3
 * Copyright (c) 2014 Peter Ross <pross@xvid.org>
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
 * Direct Stream Transfer (DST) decoder
25
 * ISO/IEC 14496-3 Part 3 Subpart 10: Technical description of lossless coding of oversampled audio
26
 */
27
28
#include "libavutil/avassert.h"
29
#include "libavutil/intreadwrite.h"
30
#include "libavutil/mem_internal.h"
31
#include "internal.h"
32
#include "get_bits.h"
33
#include "avcodec.h"
34
#include "golomb.h"
35
#include "mathops.h"
36
#include "dsd.h"
37
38
#define DST_MAX_CHANNELS 6
39
#define DST_MAX_ELEMENTS (2 * DST_MAX_CHANNELS)
40
41
#define DSD_FS44(sample_rate) (sample_rate * 8LL / 44100)
42
43
#define DST_SAMPLES_PER_FRAME(sample_rate) (588 * DSD_FS44(sample_rate))
44
45
static const int8_t fsets_code_pred_coeff[3][3] = {
46
    {  -8 },
47
    { -16,  8 },
48
    {  -9, -5, 6 },
49
};
50
51
static const int8_t probs_code_pred_coeff[3][3] = {
52
    {  -8 },
53
    { -16,  8 },
54
    { -24, 24, -8 },
55
};
56
57
typedef struct ArithCoder {
58
    unsigned int a;
59
    unsigned int c;
60
} ArithCoder;
61
62
typedef struct Table {
63
    unsigned int elements;
64
    unsigned int length[DST_MAX_ELEMENTS];
65
    int coeff[DST_MAX_ELEMENTS][128];
66
} Table;
67
68
typedef struct DSTContext {
69
    AVClass *class;
70
71
    GetBitContext gb;
72
    ArithCoder ac;
73
    Table fsets, probs;
74
    DECLARE_ALIGNED(16, uint8_t, status)[DST_MAX_CHANNELS][16];
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    DECLARE_ALIGNED(16, int16_t, filter)[DST_MAX_ELEMENTS][16][256];
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    DSDContext dsdctx[DST_MAX_CHANNELS];
77
} DSTContext;
78
79
2
static av_cold int decode_init(AVCodecContext *avctx)
80
{
81
2
    DSTContext *s = avctx->priv_data;
82
    int i;
83
84
2
    if (avctx->channels > DST_MAX_CHANNELS) {
85
        avpriv_request_sample(avctx, "Channel count %d", avctx->channels);
86
        return AVERROR_PATCHWELCOME;
87
    }
88
89
    // the sample rate is only allowed to be 64,128,256 * 44100 by ISO/IEC 14496-3:2005(E)
90
    // We are a bit more tolerant here, but this check is needed to bound the size and duration
91
2
    if (avctx->sample_rate > 512 * 44100)
92
        return AVERROR_INVALIDDATA;
93
94
95
2
    if (DST_SAMPLES_PER_FRAME(avctx->sample_rate) & 7) {
96
        return AVERROR_PATCHWELCOME;
97
    }
98
99
2
    avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
100
101
6
    for (i = 0; i < avctx->channels; i++)
102
4
        memset(s->dsdctx[i].buf, 0x69, sizeof(s->dsdctx[i].buf));
103
104
2
    ff_init_dsd_data();
105
106
2
    return 0;
107
}
108
109
10
static int read_map(GetBitContext *gb, Table *t, unsigned int map[DST_MAX_CHANNELS], int channels)
110
{
111
    int ch;
112
10
    t->elements = 1;
113
10
    map[0] = 0;
114
10
    if (!get_bits1(gb)) {
115
20
        for (ch = 1; ch < channels; ch++) {
116
10
            int bits = av_log2(t->elements) + 1;
117
10
            map[ch] = get_bits(gb, bits);
118
10
            if (map[ch] == t->elements) {
119
10
                t->elements++;
120
10
                if (t->elements >= DST_MAX_ELEMENTS)
121
                    return AVERROR_INVALIDDATA;
122
            } else if (map[ch] > t->elements) {
123
                return AVERROR_INVALIDDATA;
124
            }
125
        }
126
    } else {
127
        memset(map, 0, sizeof(*map) * DST_MAX_CHANNELS);
128
    }
129
10
    return 0;
130
}
131
132
static av_always_inline int get_sr_golomb_dst(GetBitContext *gb, unsigned int k)
133
{
134
    int v = get_ur_golomb_jpegls(gb, k, get_bits_left(gb), 0);
135
    if (v && get_bits1(gb))
136
        v = -v;
137
    return v;
138
}
139
140
40
static void read_uncoded_coeff(GetBitContext *gb, int *dst, unsigned int elements,
141
                               int coeff_bits, int is_signed, int offset)
142
{
143
    int i;
144
145
3880
    for (i = 0; i < elements; i++) {
146
3840
        dst[i] = (is_signed ? get_sbits(gb, coeff_bits) : get_bits(gb, coeff_bits)) + offset;
147
    }
148
40
}
149
150
20
static int read_table(GetBitContext *gb, Table *t, const int8_t code_pred_coeff[3][3],
151
                      int length_bits, int coeff_bits, int is_signed, int offset)
152
{
153
    unsigned int i, j, k;
154
60
    for (i = 0; i < t->elements; i++) {
155
40
        t->length[i] = get_bits(gb, length_bits) + 1;
156
40
        if (!get_bits1(gb)) {
157
40
            read_uncoded_coeff(gb, t->coeff[i], t->length[i], coeff_bits, is_signed, offset);
158
        } else {
159
            int method = get_bits(gb, 2), lsb_size;
160
            if (method == 3)
161
                return AVERROR_INVALIDDATA;
162
163
            read_uncoded_coeff(gb, t->coeff[i], method + 1, coeff_bits, is_signed, offset);
164
165
            lsb_size  = get_bits(gb, 3);
166
            for (j = method + 1; j < t->length[i]; j++) {
167
                int c, x = 0;
168
                for (k = 0; k < method + 1; k++)
169
                    x += code_pred_coeff[method][k] * (unsigned)t->coeff[i][j - k - 1];
170
                c = get_sr_golomb_dst(gb, lsb_size);
171
                if (x >= 0)
172
                    c -= (x + 4) / 8;
173
                else
174
                    c += (-x + 3) / 8;
175
                if (!is_signed) {
176
                    if (c < offset || c >= offset + (1<<coeff_bits))
177
                        return AVERROR_INVALIDDATA;
178
                }
179
                t->coeff[i][j] = c;
180
            }
181
        }
182
    }
183
20
    return 0;
184
}
185
186
10
static void ac_init(ArithCoder *ac, GetBitContext *gb)
187
{
188
10
    ac->a = 4095;
189
10
    ac->c = get_bits(gb, 12);
190
10
}
191
192
752650
static av_always_inline void ac_get(ArithCoder *ac, GetBitContext *gb, int p, int *e)
193
{
194
752650
    unsigned int k = (ac->a >> 8) | ((ac->a >> 7) & 1);
195
752650
    unsigned int q = k * p;
196
752650
    unsigned int a_q = ac->a - q;
197
198
752650
    *e = ac->c < a_q;
199
752650
    if (*e) {
200
637782
        ac->a  = a_q;
201
    } else {
202
114868
        ac->a  = q;
203
114868
        ac->c -= a_q;
204
    }
205
206
752650
    if (ac->a < 2048) {
207
247803
        int n = 11 - av_log2(ac->a);
208
247803
        ac->a <<= n;
209
247803
        ac->c = (ac->c << n) | get_bits(gb, n);
210
    }
211
752650
}
212
213
10
static uint8_t prob_dst_x_bit(int c)
214
{
215
10
    return (ff_reverse[c & 127] >> 1) + 1;
216
}
217
218
10
static void build_filter(int16_t table[DST_MAX_ELEMENTS][16][256], const Table *fsets)
219
{
220
    int i, j, k, l;
221
222
30
    for (i = 0; i < fsets->elements; i++) {
223
20
        int length = fsets->length[i];
224
225
340
        for (j = 0; j < 16; j++) {
226
320
            int total = av_clip(length - j * 8, 0, 8);
227
228
82240
            for (k = 0; k < 256; k++) {
229
81920
                int v = 0;
230
231
737280
                for (l = 0; l < total; l++)
232
655360
                    v += (((k >> l) & 1) * 2 - 1) * fsets->coeff[i][j * 8 + l];
233
81920
                table[i][j][k] = v;
234
            }
235
        }
236
    }
237
10
}
238
239
10
static int decode_frame(AVCodecContext *avctx, void *data,
240
                        int *got_frame_ptr, AVPacket *avpkt)
241
{
242
10
    unsigned samples_per_frame = DST_SAMPLES_PER_FRAME(avctx->sample_rate);
243
    unsigned map_ch_to_felem[DST_MAX_CHANNELS];
244
    unsigned map_ch_to_pelem[DST_MAX_CHANNELS];
245
    unsigned i, ch, same_map, dst_x_bit;
246
    unsigned half_prob[DST_MAX_CHANNELS];
247
10
    const int channels = avctx->channels;
248
10
    DSTContext *s = avctx->priv_data;
249
10
    GetBitContext *gb = &s->gb;
250
10
    ArithCoder *ac = &s->ac;
251
10
    AVFrame *frame = data;
252
    uint8_t *dsd;
253
    float *pcm;
254
    int ret;
255
256
10
    if (avpkt->size <= 1)
257
        return AVERROR_INVALIDDATA;
258
259
10
    frame->nb_samples = samples_per_frame / 8;
260
10
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
261
        return ret;
262
10
    dsd = frame->data[0];
263
10
    pcm = (float *)frame->data[0];
264
265
10
    if ((ret = init_get_bits8(gb, avpkt->data, avpkt->size)) < 0)
266
        return ret;
267
268
10
    if (!get_bits1(gb)) {
269
        skip_bits1(gb);
270
        if (get_bits(gb, 6))
271
            return AVERROR_INVALIDDATA;
272
        memcpy(frame->data[0], avpkt->data + 1, FFMIN(avpkt->size - 1, frame->nb_samples * channels));
273
        goto dsd;
274
    }
275
276
    /* Segmentation (10.4, 10.5, 10.6) */
277
278
10
    if (!get_bits1(gb)) {
279
        avpriv_request_sample(avctx, "Not Same Segmentation");
280
        return AVERROR_PATCHWELCOME;
281
    }
282
283
10
    if (!get_bits1(gb)) {
284
        avpriv_request_sample(avctx, "Not Same Segmentation For All Channels");
285
        return AVERROR_PATCHWELCOME;
286
    }
287
288
10
    if (!get_bits1(gb)) {
289
        avpriv_request_sample(avctx, "Not End Of Channel Segmentation");
290
        return AVERROR_PATCHWELCOME;
291
    }
292
293
    /* Mapping (10.7, 10.8, 10.9) */
294
295
10
    same_map = get_bits1(gb);
296
297
10
    if ((ret = read_map(gb, &s->fsets, map_ch_to_felem, channels)) < 0)
298
        return ret;
299
300
10
    if (same_map) {
301
10
        s->probs.elements = s->fsets.elements;
302
10
        memcpy(map_ch_to_pelem, map_ch_to_felem, sizeof(map_ch_to_felem));
303
    } else {
304
        avpriv_request_sample(avctx, "Not Same Mapping");
305
        if ((ret = read_map(gb, &s->probs, map_ch_to_pelem, channels)) < 0)
306
            return ret;
307
    }
308
309
    /* Half Probability (10.10) */
310
311
30
    for (ch = 0; ch < channels; ch++)
312
20
        half_prob[ch] = get_bits1(gb);
313
314
    /* Filter Coef Sets (10.12) */
315
316
10
    ret = read_table(gb, &s->fsets, fsets_code_pred_coeff, 7, 9, 1, 0);
317
10
    if (ret < 0)
318
        return ret;
319
320
    /* Probability Tables (10.13) */
321
322
10
    ret = read_table(gb, &s->probs, probs_code_pred_coeff, 6, 7, 0, 1);
323
10
    if (ret < 0)
324
        return ret;
325
326
    /* Arithmetic Coded Data (10.11) */
327
328
10
    if (get_bits1(gb))
329
        return AVERROR_INVALIDDATA;
330
10
    ac_init(ac, gb);
331
332
10
    build_filter(s->filter, &s->fsets);
333
334
10
    memset(s->status, 0xAA, sizeof(s->status));
335
10
    memset(dsd, 0, frame->nb_samples * 4 * channels);
336
337
10
    ac_get(ac, gb, prob_dst_x_bit(s->fsets.coeff[0][0]), &dst_x_bit);
338
339
376330
    for (i = 0; i < samples_per_frame; i++) {
340
1128960
        for (ch = 0; ch < channels; ch++) {
341
752640
            const unsigned felem = map_ch_to_felem[ch];
342
752640
            int16_t (*filter)[256] = s->filter[felem];
343
752640
            uint8_t *status = s->status[ch];
344
            int prob, residual, v;
345
346
#define F(x) filter[(x)][status[(x)]]
347
752640
            const int16_t predict = F( 0) + F( 1) + F( 2) + F( 3) +
348
752640
                                    F( 4) + F( 5) + F( 6) + F( 7) +
349
752640
                                    F( 8) + F( 9) + F(10) + F(11) +
350
752640
                                    F(12) + F(13) + F(14) + F(15);
351
#undef F
352
353

752640
            if (!half_prob[ch] || i >= s->fsets.length[felem]) {
354
750080
                unsigned pelem = map_ch_to_pelem[ch];
355
750080
                unsigned index = FFABS(predict) >> 3;
356
750080
                prob = s->probs.coeff[pelem][FFMIN(index, s->probs.length[pelem] - 1)];
357
            } else {
358
2560
                prob = 128;
359
            }
360
361
752640
            ac_get(ac, gb, prob, &residual);
362
752640
            v = ((predict >> 15) ^ residual) & 1;
363
752640
            dsd[((i >> 3) * channels + ch) << 2] |= v << (7 - (i & 0x7 ));
364
365
752640
            AV_WL64A(status + 8, (AV_RL64A(status + 8) << 1) | ((AV_RL64A(status) >> 63) & 1));
366
752640
            AV_WL64A(status, (AV_RL64A(status) << 1) | v);
367
        }
368
    }
369
370
10
dsd:
371
30
    for (i = 0; i < channels; i++) {
372
20
        ff_dsd2pcm_translate(&s->dsdctx[i], frame->nb_samples, 0,
373
20
                             frame->data[0] + i * 4,
374
20
                             channels * 4, pcm + i, channels);
375
    }
376
377
10
    *got_frame_ptr = 1;
378
379
10
    return avpkt->size;
380
}
381
382
AVCodec ff_dst_decoder = {
383
    .name           = "dst",
384
    .long_name      = NULL_IF_CONFIG_SMALL("DST (Digital Stream Transfer)"),
385
    .type           = AVMEDIA_TYPE_AUDIO,
386
    .id             = AV_CODEC_ID_DST,
387
    .priv_data_size = sizeof(DSTContext),
388
    .init           = decode_init,
389
    .decode         = decode_frame,
390
    .capabilities   = AV_CODEC_CAP_DR1,
391
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
392
                                                      AV_SAMPLE_FMT_NONE },
393
    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
394
};