GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/dstdec.c Lines: 124 174 71.3 %
Date: 2019-11-20 04:07:19 Branches: 53 96 55.2 %

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 "internal.h"
31
#include "get_bits.h"
32
#include "avcodec.h"
33
#include "golomb.h"
34
#include "mathops.h"
35
#include "dsd.h"
36
37
#define DST_MAX_CHANNELS 6
38
#define DST_MAX_ELEMENTS (2 * DST_MAX_CHANNELS)
39
40
#define DSD_FS44(sample_rate) (sample_rate * 8LL / 44100)
41
42
#define DST_SAMPLES_PER_FRAME(sample_rate) (588 * DSD_FS44(sample_rate))
43
44
static const int8_t fsets_code_pred_coeff[3][3] = {
45
    {  -8 },
46
    { -16,  8 },
47
    {  -9, -5, 6 },
48
};
49
50
static const int8_t probs_code_pred_coeff[3][3] = {
51
    {  -8 },
52
    { -16,  8 },
53
    { -24, 24, -8 },
54
};
55
56
typedef struct ArithCoder {
57
    unsigned int a;
58
    unsigned int c;
59
    int overread;
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];
75
    DECLARE_ALIGNED(16, int16_t, filter)[DST_MAX_ELEMENTS][16][256];
76
    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
2
    avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
90
91
6
    for (i = 0; i < avctx->channels; i++)
92
4
        memset(s->dsdctx[i].buf, 0x69, sizeof(s->dsdctx[i].buf));
93
94
2
    ff_init_dsd_data();
95
96
2
    return 0;
97
}
98
99
10
static int read_map(GetBitContext *gb, Table *t, unsigned int map[DST_MAX_CHANNELS], int channels)
100
{
101
    int ch;
102
10
    t->elements = 1;
103
10
    map[0] = 0;
104
10
    if (!get_bits1(gb)) {
105
20
        for (ch = 1; ch < channels; ch++) {
106
10
            int bits = av_log2(t->elements) + 1;
107
10
            map[ch] = get_bits(gb, bits);
108
10
            if (map[ch] == t->elements) {
109
10
                t->elements++;
110
10
                if (t->elements >= DST_MAX_ELEMENTS)
111
                    return AVERROR_INVALIDDATA;
112
            } else if (map[ch] > t->elements) {
113
                return AVERROR_INVALIDDATA;
114
            }
115
        }
116
    } else {
117
        memset(map, 0, sizeof(*map) * DST_MAX_CHANNELS);
118
    }
119
10
    return 0;
120
}
121
122
static av_always_inline int get_sr_golomb_dst(GetBitContext *gb, unsigned int k)
123
{
124
    int v = get_ur_golomb(gb, k, get_bits_left(gb), 0);
125
    if (v && get_bits1(gb))
126
        v = -v;
127
    return v;
128
}
129
130
40
static void read_uncoded_coeff(GetBitContext *gb, int *dst, unsigned int elements,
131
                               int coeff_bits, int is_signed, int offset)
132
{
133
    int i;
134
135
3880
    for (i = 0; i < elements; i++) {
136
3840
        dst[i] = (is_signed ? get_sbits(gb, coeff_bits) : get_bits(gb, coeff_bits)) + offset;
137
    }
138
40
}
139
140
20
static int read_table(GetBitContext *gb, Table *t, const int8_t code_pred_coeff[3][3],
141
                      int length_bits, int coeff_bits, int is_signed, int offset)
142
{
143
    unsigned int i, j, k;
144
60
    for (i = 0; i < t->elements; i++) {
145
40
        t->length[i] = get_bits(gb, length_bits) + 1;
146
40
        if (!get_bits1(gb)) {
147
40
            read_uncoded_coeff(gb, t->coeff[i], t->length[i], coeff_bits, is_signed, offset);
148
        } else {
149
            int method = get_bits(gb, 2), lsb_size;
150
            if (method == 3)
151
                return AVERROR_INVALIDDATA;
152
153
            read_uncoded_coeff(gb, t->coeff[i], method + 1, coeff_bits, is_signed, offset);
154
155
            lsb_size  = get_bits(gb, 3);
156
            for (j = method + 1; j < t->length[i]; j++) {
157
                int c, x = 0;
158
                for (k = 0; k < method + 1; k++)
159
                    x += code_pred_coeff[method][k] * t->coeff[i][j - k - 1];
160
                c = get_sr_golomb_dst(gb, lsb_size);
161
                if (x >= 0)
162
                    c -= (x + 4) / 8;
163
                else
164
                    c += (-x + 3) / 8;
165
                if (!is_signed) {
166
                    if (c < offset || c >= offset + (1<<coeff_bits))
167
                        return AVERROR_INVALIDDATA;
168
                }
169
                t->coeff[i][j] = c;
170
            }
171
        }
172
    }
173
20
    return 0;
174
}
175
176
10
static void ac_init(ArithCoder *ac, GetBitContext *gb)
177
{
178
10
    ac->a = 4095;
179
10
    ac->c = get_bits(gb, 12);
180
10
    ac->overread = 0;
181
10
}
182
183
752650
static av_always_inline void ac_get(ArithCoder *ac, GetBitContext *gb, int p, int *e)
184
{
185
752650
    unsigned int k = (ac->a >> 8) | ((ac->a >> 7) & 1);
186
752650
    unsigned int q = k * p;
187
752650
    unsigned int a_q = ac->a - q;
188
189
752650
    *e = ac->c < a_q;
190
752650
    if (*e) {
191
637782
        ac->a  = a_q;
192
    } else {
193
114868
        ac->a  = q;
194
114868
        ac->c -= a_q;
195
    }
196
197
752650
    if (ac->a < 2048) {
198
247803
        int n = 11 - av_log2(ac->a);
199
247803
        ac->a <<= n;
200
247803
        if (get_bits_left(gb) < n)
201
70
            ac->overread ++;
202
247803
        ac->c = (ac->c << n) | get_bits(gb, n);
203
    }
204
752650
}
205
206
10
static uint8_t prob_dst_x_bit(int c)
207
{
208
10
    return (ff_reverse[c & 127] >> 1) + 1;
209
}
210
211
10
static void build_filter(int16_t table[DST_MAX_ELEMENTS][16][256], const Table *fsets)
212
{
213
    int i, j, k, l;
214
215
30
    for (i = 0; i < fsets->elements; i++) {
216
20
        int length = fsets->length[i];
217
218
340
        for (j = 0; j < 16; j++) {
219
320
            int total = av_clip(length - j * 8, 0, 8);
220
221
82240
            for (k = 0; k < 256; k++) {
222
81920
                int v = 0;
223
224
737280
                for (l = 0; l < total; l++)
225
655360
                    v += (((k >> l) & 1) * 2 - 1) * fsets->coeff[i][j * 8 + l];
226
81920
                table[i][j][k] = v;
227
            }
228
        }
229
    }
230
10
}
231
232
10
static int decode_frame(AVCodecContext *avctx, void *data,
233
                        int *got_frame_ptr, AVPacket *avpkt)
234
{
235
10
    unsigned samples_per_frame = DST_SAMPLES_PER_FRAME(avctx->sample_rate);
236
    unsigned map_ch_to_felem[DST_MAX_CHANNELS];
237
    unsigned map_ch_to_pelem[DST_MAX_CHANNELS];
238
    unsigned i, ch, same_map, dst_x_bit;
239
    unsigned half_prob[DST_MAX_CHANNELS];
240
10
    const int channels = avctx->channels;
241
10
    DSTContext *s = avctx->priv_data;
242
10
    GetBitContext *gb = &s->gb;
243
10
    ArithCoder *ac = &s->ac;
244
10
    AVFrame *frame = data;
245
    uint8_t *dsd;
246
    float *pcm;
247
    int ret;
248
249
10
    if (avpkt->size <= 1)
250
        return AVERROR_INVALIDDATA;
251
252
10
    frame->nb_samples = samples_per_frame / 8;
253
10
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
254
        return ret;
255
10
    dsd = frame->data[0];
256
10
    pcm = (float *)frame->data[0];
257
258
10
    if ((ret = init_get_bits8(gb, avpkt->data, avpkt->size)) < 0)
259
        return ret;
260
261
10
    if (!get_bits1(gb)) {
262
        skip_bits1(gb);
263
        if (get_bits(gb, 6))
264
            return AVERROR_INVALIDDATA;
265
        memcpy(frame->data[0], avpkt->data + 1, FFMIN(avpkt->size - 1, frame->nb_samples * avctx->channels));
266
        goto dsd;
267
    }
268
269
    /* Segmentation (10.4, 10.5, 10.6) */
270
271
10
    if (!get_bits1(gb)) {
272
        avpriv_request_sample(avctx, "Not Same Segmentation");
273
        return AVERROR_PATCHWELCOME;
274
    }
275
276
10
    if (!get_bits1(gb)) {
277
        avpriv_request_sample(avctx, "Not Same Segmentation For All Channels");
278
        return AVERROR_PATCHWELCOME;
279
    }
280
281
10
    if (!get_bits1(gb)) {
282
        avpriv_request_sample(avctx, "Not End Of Channel Segmentation");
283
        return AVERROR_PATCHWELCOME;
284
    }
285
286
    /* Mapping (10.7, 10.8, 10.9) */
287
288
10
    same_map = get_bits1(gb);
289
290
10
    if ((ret = read_map(gb, &s->fsets, map_ch_to_felem, avctx->channels)) < 0)
291
        return ret;
292
293
10
    if (same_map) {
294
10
        s->probs.elements = s->fsets.elements;
295
10
        memcpy(map_ch_to_pelem, map_ch_to_felem, sizeof(map_ch_to_felem));
296
    } else {
297
        avpriv_request_sample(avctx, "Not Same Mapping");
298
        if ((ret = read_map(gb, &s->probs, map_ch_to_pelem, avctx->channels)) < 0)
299
            return ret;
300
    }
301
302
    /* Half Probability (10.10) */
303
304
30
    for (ch = 0; ch < avctx->channels; ch++)
305
20
        half_prob[ch] = get_bits1(gb);
306
307
    /* Filter Coef Sets (10.12) */
308
309
10
    ret = read_table(gb, &s->fsets, fsets_code_pred_coeff, 7, 9, 1, 0);
310
10
    if (ret < 0)
311
        return ret;
312
313
    /* Probability Tables (10.13) */
314
315
10
    ret = read_table(gb, &s->probs, probs_code_pred_coeff, 6, 7, 0, 1);
316
10
    if (ret < 0)
317
        return ret;
318
319
    /* Arithmetic Coded Data (10.11) */
320
321
10
    if (get_bits1(gb))
322
        return AVERROR_INVALIDDATA;
323
10
    ac_init(ac, gb);
324
325
10
    build_filter(s->filter, &s->fsets);
326
327
10
    memset(s->status, 0xAA, sizeof(s->status));
328
10
    memset(dsd, 0, frame->nb_samples * 4 * avctx->channels);
329
330
10
    ac_get(ac, gb, prob_dst_x_bit(s->fsets.coeff[0][0]), &dst_x_bit);
331
332
376330
    for (i = 0; i < samples_per_frame; i++) {
333
1128960
        for (ch = 0; ch < channels; ch++) {
334
752640
            const unsigned felem = map_ch_to_felem[ch];
335
752640
            int16_t (*filter)[256] = s->filter[felem];
336
752640
            uint8_t *status = s->status[ch];
337
            int prob, residual, v;
338
339
#define F(x) filter[(x)][status[(x)]]
340
752640
            const int16_t predict = F( 0) + F( 1) + F( 2) + F( 3) +
341
752640
                                    F( 4) + F( 5) + F( 6) + F( 7) +
342
752640
                                    F( 8) + F( 9) + F(10) + F(11) +
343
752640
                                    F(12) + F(13) + F(14) + F(15);
344
#undef F
345
346

752640
            if (!half_prob[ch] || i >= s->fsets.length[felem]) {
347
750080
                unsigned pelem = map_ch_to_pelem[ch];
348
750080
                unsigned index = FFABS(predict) >> 3;
349
750080
                prob = s->probs.coeff[pelem][FFMIN(index, s->probs.length[pelem] - 1)];
350
            } else {
351
2560
                prob = 128;
352
            }
353
354
752640
            if (ac->overread > 16)
355
                return AVERROR_INVALIDDATA;
356
357
752640
            ac_get(ac, gb, prob, &residual);
358
752640
            v = ((predict >> 15) ^ residual) & 1;
359
752640
            dsd[((i >> 3) * channels + ch) << 2] |= v << (7 - (i & 0x7 ));
360
361
752640
            AV_WL64A(status + 8, (AV_RL64A(status + 8) << 1) | ((AV_RL64A(status) >> 63) & 1));
362
752640
            AV_WL64A(status, (AV_RL64A(status) << 1) | v);
363
        }
364
    }
365
366
10
dsd:
367
30
    for (i = 0; i < avctx->channels; i++) {
368
20
        ff_dsd2pcm_translate(&s->dsdctx[i], frame->nb_samples, 0,
369
20
                             frame->data[0] + i * 4,
370
20
                             avctx->channels * 4, pcm + i, avctx->channels);
371
    }
372
373
10
    *got_frame_ptr = 1;
374
375
10
    return avpkt->size;
376
}
377
378
AVCodec ff_dst_decoder = {
379
    .name           = "dst",
380
    .long_name      = NULL_IF_CONFIG_SMALL("DST (Digital Stream Transfer)"),
381
    .type           = AVMEDIA_TYPE_AUDIO,
382
    .id             = AV_CODEC_ID_DST,
383
    .priv_data_size = sizeof(DSTContext),
384
    .init           = decode_init,
385
    .decode         = decode_frame,
386
    .capabilities   = AV_CODEC_CAP_DR1,
387
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
388
                                                      AV_SAMPLE_FMT_NONE },
389
};