FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/dstdec.c
Date: 2022-07-07 01:21:54
Exec Total Coverage
Lines: 121 172 70.3%
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/intreadwrite.h"
29 #include "libavutil/mem_internal.h"
30 #include "libavutil/reverse.h"
31 #include "codec_internal.h"
32 #include "internal.h"
33 #include "get_bits.h"
34 #include "avcodec.h"
35 #include "golomb.h"
36 #include "mathops.h"
37 #include "dsd.h"
38
39 #define DST_MAX_CHANNELS 6
40 #define DST_MAX_ELEMENTS (2 * DST_MAX_CHANNELS)
41
42 #define DSD_FS44(sample_rate) (sample_rate * 8LL / 44100)
43
44 #define DST_SAMPLES_PER_FRAME(sample_rate) (588 * DSD_FS44(sample_rate))
45
46 static const int8_t fsets_code_pred_coeff[3][3] = {
47 { -8 },
48 { -16, 8 },
49 { -9, -5, 6 },
50 };
51
52 static const int8_t probs_code_pred_coeff[3][3] = {
53 { -8 },
54 { -16, 8 },
55 { -24, 24, -8 },
56 };
57
58 typedef struct ArithCoder {
59 unsigned int a;
60 unsigned int c;
61 } ArithCoder;
62
63 typedef struct Table {
64 unsigned int elements;
65 unsigned int length[DST_MAX_ELEMENTS];
66 int coeff[DST_MAX_ELEMENTS][128];
67 } Table;
68
69 typedef struct DSTContext {
70 AVClass *class;
71
72 GetBitContext gb;
73 ArithCoder ac;
74 Table fsets, probs;
75 DECLARE_ALIGNED(16, uint8_t, status)[DST_MAX_CHANNELS][16];
76 DECLARE_ALIGNED(16, int16_t, filter)[DST_MAX_ELEMENTS][16][256];
77 DSDContext dsdctx[DST_MAX_CHANNELS];
78 } DSTContext;
79
80 2 static av_cold int decode_init(AVCodecContext *avctx)
81 {
82 2 DSTContext *s = avctx->priv_data;
83 int i;
84
85
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2 if (avctx->ch_layout.nb_channels > DST_MAX_CHANNELS) {
86 avpriv_request_sample(avctx, "Channel count %d", avctx->ch_layout.nb_channels);
87 return AVERROR_PATCHWELCOME;
88 }
89
90 // the sample rate is only allowed to be 64,128,256 * 44100 by ISO/IEC 14496-3:2005(E)
91 // We are a bit more tolerant here, but this check is needed to bound the size and duration
92
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2 if (avctx->sample_rate > 512 * 44100)
93 return AVERROR_INVALIDDATA;
94
95
96
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2 if (DST_SAMPLES_PER_FRAME(avctx->sample_rate) & 7) {
97 return AVERROR_PATCHWELCOME;
98 }
99
100 2 avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
101
102
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6 for (i = 0; i < avctx->ch_layout.nb_channels; i++)
103 4 memset(s->dsdctx[i].buf, 0x69, sizeof(s->dsdctx[i].buf));
104
105 2 ff_init_dsd_data();
106
107 2 return 0;
108 }
109
110 10 static int read_map(GetBitContext *gb, Table *t, unsigned int map[DST_MAX_CHANNELS], int channels)
111 {
112 int ch;
113 10 t->elements = 1;
114 10 map[0] = 0;
115
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10 if (!get_bits1(gb)) {
116
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20 for (ch = 1; ch < channels; ch++) {
117 10 int bits = av_log2(t->elements) + 1;
118 10 map[ch] = get_bits(gb, bits);
119
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10 if (map[ch] == t->elements) {
120 10 t->elements++;
121
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10 if (t->elements >= DST_MAX_ELEMENTS)
122 return AVERROR_INVALIDDATA;
123 } else if (map[ch] > t->elements) {
124 return AVERROR_INVALIDDATA;
125 }
126 }
127 } else {
128 memset(map, 0, sizeof(*map) * DST_MAX_CHANNELS);
129 }
130 10 return 0;
131 }
132
133 static av_always_inline int get_sr_golomb_dst(GetBitContext *gb, unsigned int k)
134 {
135 int v = get_ur_golomb_jpegls(gb, k, get_bits_left(gb), 0);
136 if (v && get_bits1(gb))
137 v = -v;
138 return v;
139 }
140
141 40 static void read_uncoded_coeff(GetBitContext *gb, int *dst, unsigned int elements,
142 int coeff_bits, int is_signed, int offset)
143 {
144 int i;
145
146
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3880 for (i = 0; i < elements; i++) {
147
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3840 dst[i] = (is_signed ? get_sbits(gb, coeff_bits) : get_bits(gb, coeff_bits)) + offset;
148 }
149 40 }
150
151 20 static int read_table(GetBitContext *gb, Table *t, const int8_t code_pred_coeff[3][3],
152 int length_bits, int coeff_bits, int is_signed, int offset)
153 {
154 unsigned int i, j, k;
155
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60 for (i = 0; i < t->elements; i++) {
156 40 t->length[i] = get_bits(gb, length_bits) + 1;
157
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40 if (!get_bits1(gb)) {
158 40 read_uncoded_coeff(gb, t->coeff[i], t->length[i], coeff_bits, is_signed, offset);
159 } else {
160 int method = get_bits(gb, 2), lsb_size;
161 if (method == 3)
162 return AVERROR_INVALIDDATA;
163
164 read_uncoded_coeff(gb, t->coeff[i], method + 1, coeff_bits, is_signed, offset);
165
166 lsb_size = get_bits(gb, 3);
167 for (j = method + 1; j < t->length[i]; j++) {
168 int c, x = 0;
169 for (k = 0; k < method + 1; k++)
170 x += code_pred_coeff[method][k] * (unsigned)t->coeff[i][j - k - 1];
171 c = get_sr_golomb_dst(gb, lsb_size);
172 if (x >= 0)
173 c -= (x + 4) / 8;
174 else
175 c += (-x + 3) / 8;
176 if (!is_signed) {
177 if (c < offset || c >= offset + (1<<coeff_bits))
178 return AVERROR_INVALIDDATA;
179 }
180 t->coeff[i][j] = c;
181 }
182 }
183 }
184 20 return 0;
185 }
186
187 10 static void ac_init(ArithCoder *ac, GetBitContext *gb)
188 {
189 10 ac->a = 4095;
190 10 ac->c = get_bits(gb, 12);
191 10 }
192
193 752650 static av_always_inline void ac_get(ArithCoder *ac, GetBitContext *gb, int p, int *e)
194 {
195 752650 unsigned int k = (ac->a >> 8) | ((ac->a >> 7) & 1);
196 752650 unsigned int q = k * p;
197 752650 unsigned int a_q = ac->a - q;
198
199 752650 *e = ac->c < a_q;
200
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752650 if (*e) {
201 637782 ac->a = a_q;
202 } else {
203 114868 ac->a = q;
204 114868 ac->c -= a_q;
205 }
206
207
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752650 if (ac->a < 2048) {
208 247803 int n = 11 - av_log2(ac->a);
209 247803 ac->a <<= n;
210 247803 ac->c = (ac->c << n) | get_bits(gb, n);
211 }
212 752650 }
213
214 10 static uint8_t prob_dst_x_bit(int c)
215 {
216 10 return (ff_reverse[c & 127] >> 1) + 1;
217 }
218
219 10 static void build_filter(int16_t table[DST_MAX_ELEMENTS][16][256], const Table *fsets)
220 {
221 int i, j, k, l;
222
223
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30 for (i = 0; i < fsets->elements; i++) {
224 20 int length = fsets->length[i];
225
226
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340 for (j = 0; j < 16; j++) {
227 320 int total = av_clip(length - j * 8, 0, 8);
228
229
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82240 for (k = 0; k < 256; k++) {
230 81920 int v = 0;
231
232
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737280 for (l = 0; l < total; l++)
233 655360 v += (((k >> l) & 1) * 2 - 1) * fsets->coeff[i][j * 8 + l];
234 81920 table[i][j][k] = v;
235 }
236 }
237 }
238 10 }
239
240 10 static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
241 int *got_frame_ptr, AVPacket *avpkt)
242 {
243 10 unsigned samples_per_frame = DST_SAMPLES_PER_FRAME(avctx->sample_rate);
244 unsigned map_ch_to_felem[DST_MAX_CHANNELS];
245 unsigned map_ch_to_pelem[DST_MAX_CHANNELS];
246 unsigned i, ch, same_map, dst_x_bit;
247 unsigned half_prob[DST_MAX_CHANNELS];
248 10 const int channels = avctx->ch_layout.nb_channels;
249 10 DSTContext *s = avctx->priv_data;
250 10 GetBitContext *gb = &s->gb;
251 10 ArithCoder *ac = &s->ac;
252 uint8_t *dsd;
253 float *pcm;
254 int ret;
255
256
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10 if (avpkt->size <= 1)
257 return AVERROR_INVALIDDATA;
258
259 10 frame->nb_samples = samples_per_frame / 8;
260
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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
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10 if ((ret = init_get_bits8(gb, avpkt->data, avpkt->size)) < 0)
266 return ret;
267
268
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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
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10 if (!get_bits1(gb)) {
279 avpriv_request_sample(avctx, "Not Same Segmentation");
280 return AVERROR_PATCHWELCOME;
281 }
282
283
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10 if (!get_bits1(gb)) {
284 avpriv_request_sample(avctx, "Not Same Segmentation For All Channels");
285 return AVERROR_PATCHWELCOME;
286 }
287
288
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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
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10 if ((ret = read_map(gb, &s->fsets, map_ch_to_felem, channels)) < 0)
298 return ret;
299
300
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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
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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
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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
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10 if (ret < 0)
324 return ret;
325
326 /* Arithmetic Coded Data (10.11) */
327
328
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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
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376330 for (i = 0; i < samples_per_frame; i++) {
340
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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
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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
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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 const FFCodec ff_dst_decoder = {
383 .p.name = "dst",
384 .p.long_name = NULL_IF_CONFIG_SMALL("DST (Digital Stream Transfer)"),
385 .p.type = AVMEDIA_TYPE_AUDIO,
386 .p.id = AV_CODEC_ID_DST,
387 .priv_data_size = sizeof(DSTContext),
388 .init = decode_init,
389 FF_CODEC_DECODE_CB(decode_frame),
390 .p.capabilities = AV_CODEC_CAP_DR1,
391 .p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
392 AV_SAMPLE_FMT_NONE },
393 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
394 };
395