FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/dstdec.c
Date: 2021-09-24 20:55:06
Exec Total Coverage
Lines: 122 173 70.5%
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 "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 } ArithCoder;
60
61 typedef struct Table {
62 unsigned int elements;
63 unsigned int length[DST_MAX_ELEMENTS];
64 int coeff[DST_MAX_ELEMENTS][128];
65 } Table;
66
67 typedef struct DSTContext {
68 AVClass *class;
69
70 GetBitContext gb;
71 ArithCoder ac;
72 Table fsets, probs;
73 DECLARE_ALIGNED(16, uint8_t, status)[DST_MAX_CHANNELS][16];
74 DECLARE_ALIGNED(16, int16_t, filter)[DST_MAX_ELEMENTS][16][256];
75 DSDContext dsdctx[DST_MAX_CHANNELS];
76 } DSTContext;
77
78 2 static av_cold int decode_init(AVCodecContext *avctx)
79 {
80 2 DSTContext *s = avctx->priv_data;
81 int i;
82
83
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2 if (avctx->channels > DST_MAX_CHANNELS) {
84 avpriv_request_sample(avctx, "Channel count %d", avctx->channels);
85 return AVERROR_PATCHWELCOME;
86 }
87
88 // the sample rate is only allowed to be 64,128,256 * 44100 by ISO/IEC 14496-3:2005(E)
89 // We are a bit more tolerant here, but this check is needed to bound the size and duration
90
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2 if (avctx->sample_rate > 512 * 44100)
91 return AVERROR_INVALIDDATA;
92
93
94
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2 if (DST_SAMPLES_PER_FRAME(avctx->sample_rate) & 7) {
95 return AVERROR_PATCHWELCOME;
96 }
97
98 2 avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
99
100
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6 for (i = 0; i < avctx->channels; i++)
101 4 memset(s->dsdctx[i].buf, 0x69, sizeof(s->dsdctx[i].buf));
102
103 2 ff_init_dsd_data();
104
105 2 return 0;
106 }
107
108 10 static int read_map(GetBitContext *gb, Table *t, unsigned int map[DST_MAX_CHANNELS], int channels)
109 {
110 int ch;
111 10 t->elements = 1;
112 10 map[0] = 0;
113
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10 if (!get_bits1(gb)) {
114
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20 for (ch = 1; ch < channels; ch++) {
115 10 int bits = av_log2(t->elements) + 1;
116 10 map[ch] = get_bits(gb, bits);
117
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10 if (map[ch] == t->elements) {
118 10 t->elements++;
119
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10 if (t->elements >= DST_MAX_ELEMENTS)
120 return AVERROR_INVALIDDATA;
121 } else if (map[ch] > t->elements) {
122 return AVERROR_INVALIDDATA;
123 }
124 }
125 } else {
126 memset(map, 0, sizeof(*map) * DST_MAX_CHANNELS);
127 }
128 10 return 0;
129 }
130
131 static av_always_inline int get_sr_golomb_dst(GetBitContext *gb, unsigned int k)
132 {
133 int v = get_ur_golomb_jpegls(gb, k, get_bits_left(gb), 0);
134 if (v && get_bits1(gb))
135 v = -v;
136 return v;
137 }
138
139 40 static void read_uncoded_coeff(GetBitContext *gb, int *dst, unsigned int elements,
140 int coeff_bits, int is_signed, int offset)
141 {
142 int i;
143
144
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3880 for (i = 0; i < elements; i++) {
145
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3840 dst[i] = (is_signed ? get_sbits(gb, coeff_bits) : get_bits(gb, coeff_bits)) + offset;
146 }
147 40 }
148
149 20 static int read_table(GetBitContext *gb, Table *t, const int8_t code_pred_coeff[3][3],
150 int length_bits, int coeff_bits, int is_signed, int offset)
151 {
152 unsigned int i, j, k;
153
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60 for (i = 0; i < t->elements; i++) {
154 40 t->length[i] = get_bits(gb, length_bits) + 1;
155
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40 if (!get_bits1(gb)) {
156 40 read_uncoded_coeff(gb, t->coeff[i], t->length[i], coeff_bits, is_signed, offset);
157 } else {
158 int method = get_bits(gb, 2), lsb_size;
159 if (method == 3)
160 return AVERROR_INVALIDDATA;
161
162 read_uncoded_coeff(gb, t->coeff[i], method + 1, coeff_bits, is_signed, offset);
163
164 lsb_size = get_bits(gb, 3);
165 for (j = method + 1; j < t->length[i]; j++) {
166 int c, x = 0;
167 for (k = 0; k < method + 1; k++)
168 x += code_pred_coeff[method][k] * (unsigned)t->coeff[i][j - k - 1];
169 c = get_sr_golomb_dst(gb, lsb_size);
170 if (x >= 0)
171 c -= (x + 4) / 8;
172 else
173 c += (-x + 3) / 8;
174 if (!is_signed) {
175 if (c < offset || c >= offset + (1<<coeff_bits))
176 return AVERROR_INVALIDDATA;
177 }
178 t->coeff[i][j] = c;
179 }
180 }
181 }
182 20 return 0;
183 }
184
185 10 static void ac_init(ArithCoder *ac, GetBitContext *gb)
186 {
187 10 ac->a = 4095;
188 10 ac->c = get_bits(gb, 12);
189 10 }
190
191 752650 static av_always_inline void ac_get(ArithCoder *ac, GetBitContext *gb, int p, int *e)
192 {
193 752650 unsigned int k = (ac->a >> 8) | ((ac->a >> 7) & 1);
194 752650 unsigned int q = k * p;
195 752650 unsigned int a_q = ac->a - q;
196
197 752650 *e = ac->c < a_q;
198
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752650 if (*e) {
199 637782 ac->a = a_q;
200 } else {
201 114868 ac->a = q;
202 114868 ac->c -= a_q;
203 }
204
205
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752650 if (ac->a < 2048) {
206 247803 int n = 11 - av_log2(ac->a);
207 247803 ac->a <<= n;
208 247803 ac->c = (ac->c << n) | get_bits(gb, n);
209 }
210 752650 }
211
212 10 static uint8_t prob_dst_x_bit(int c)
213 {
214 10 return (ff_reverse[c & 127] >> 1) + 1;
215 }
216
217 10 static void build_filter(int16_t table[DST_MAX_ELEMENTS][16][256], const Table *fsets)
218 {
219 int i, j, k, l;
220
221
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30 for (i = 0; i < fsets->elements; i++) {
222 20 int length = fsets->length[i];
223
224
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340 for (j = 0; j < 16; j++) {
225 320 int total = av_clip(length - j * 8, 0, 8);
226
227
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82240 for (k = 0; k < 256; k++) {
228 81920 int v = 0;
229
230
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737280 for (l = 0; l < total; l++)
231 655360 v += (((k >> l) & 1) * 2 - 1) * fsets->coeff[i][j * 8 + l];
232 81920 table[i][j][k] = v;
233 }
234 }
235 }
236 10 }
237
238 10 static int decode_frame(AVCodecContext *avctx, void *data,
239 int *got_frame_ptr, AVPacket *avpkt)
240 {
241 10 unsigned samples_per_frame = DST_SAMPLES_PER_FRAME(avctx->sample_rate);
242 unsigned map_ch_to_felem[DST_MAX_CHANNELS];
243 unsigned map_ch_to_pelem[DST_MAX_CHANNELS];
244 unsigned i, ch, same_map, dst_x_bit;
245 unsigned half_prob[DST_MAX_CHANNELS];
246 10 const int channels = avctx->channels;
247 10 DSTContext *s = avctx->priv_data;
248 10 GetBitContext *gb = &s->gb;
249 10 ArithCoder *ac = &s->ac;
250 10 AVFrame *frame = data;
251 uint8_t *dsd;
252 float *pcm;
253 int ret;
254
255
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10 if (avpkt->size <= 1)
256 return AVERROR_INVALIDDATA;
257
258 10 frame->nb_samples = samples_per_frame / 8;
259
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10 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
260 return ret;
261 10 dsd = frame->data[0];
262 10 pcm = (float *)frame->data[0];
263
264
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10 if ((ret = init_get_bits8(gb, avpkt->data, avpkt->size)) < 0)
265 return ret;
266
267
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10 if (!get_bits1(gb)) {
268 skip_bits1(gb);
269 if (get_bits(gb, 6))
270 return AVERROR_INVALIDDATA;
271 memcpy(frame->data[0], avpkt->data + 1, FFMIN(avpkt->size - 1, frame->nb_samples * channels));
272 goto dsd;
273 }
274
275 /* Segmentation (10.4, 10.5, 10.6) */
276
277
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10 if (!get_bits1(gb)) {
278 avpriv_request_sample(avctx, "Not Same Segmentation");
279 return AVERROR_PATCHWELCOME;
280 }
281
282
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10 if (!get_bits1(gb)) {
283 avpriv_request_sample(avctx, "Not Same Segmentation For All Channels");
284 return AVERROR_PATCHWELCOME;
285 }
286
287
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10 if (!get_bits1(gb)) {
288 avpriv_request_sample(avctx, "Not End Of Channel Segmentation");
289 return AVERROR_PATCHWELCOME;
290 }
291
292 /* Mapping (10.7, 10.8, 10.9) */
293
294 10 same_map = get_bits1(gb);
295
296
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10 if ((ret = read_map(gb, &s->fsets, map_ch_to_felem, channels)) < 0)
297 return ret;
298
299
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10 if (same_map) {
300 10 s->probs.elements = s->fsets.elements;
301 10 memcpy(map_ch_to_pelem, map_ch_to_felem, sizeof(map_ch_to_felem));
302 } else {
303 avpriv_request_sample(avctx, "Not Same Mapping");
304 if ((ret = read_map(gb, &s->probs, map_ch_to_pelem, channels)) < 0)
305 return ret;
306 }
307
308 /* Half Probability (10.10) */
309
310
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30 for (ch = 0; ch < channels; ch++)
311 20 half_prob[ch] = get_bits1(gb);
312
313 /* Filter Coef Sets (10.12) */
314
315 10 ret = read_table(gb, &s->fsets, fsets_code_pred_coeff, 7, 9, 1, 0);
316
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10 if (ret < 0)
317 return ret;
318
319 /* Probability Tables (10.13) */
320
321 10 ret = read_table(gb, &s->probs, probs_code_pred_coeff, 6, 7, 0, 1);
322
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10 if (ret < 0)
323 return ret;
324
325 /* Arithmetic Coded Data (10.11) */
326
327
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10 if (get_bits1(gb))
328 return AVERROR_INVALIDDATA;
329 10 ac_init(ac, gb);
330
331 10 build_filter(s->filter, &s->fsets);
332
333 10 memset(s->status, 0xAA, sizeof(s->status));
334 10 memset(dsd, 0, frame->nb_samples * 4 * channels);
335
336 10 ac_get(ac, gb, prob_dst_x_bit(s->fsets.coeff[0][0]), &dst_x_bit);
337
338
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376330 for (i = 0; i < samples_per_frame; i++) {
339
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1128960 for (ch = 0; ch < channels; ch++) {
340 752640 const unsigned felem = map_ch_to_felem[ch];
341 752640 int16_t (*filter)[256] = s->filter[felem];
342 752640 uint8_t *status = s->status[ch];
343 int prob, residual, v;
344
345 #define F(x) filter[(x)][status[(x)]]
346 752640 const int16_t predict = F( 0) + F( 1) + F( 2) + F( 3) +
347 752640 F( 4) + F( 5) + F( 6) + F( 7) +
348 752640 F( 8) + F( 9) + F(10) + F(11) +
349 752640 F(12) + F(13) + F(14) + F(15);
350 #undef F
351
352
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752640 if (!half_prob[ch] || i >= s->fsets.length[felem]) {
353 750080 unsigned pelem = map_ch_to_pelem[ch];
354 750080 unsigned index = FFABS(predict) >> 3;
355 750080 prob = s->probs.coeff[pelem][FFMIN(index, s->probs.length[pelem] - 1)];
356 } else {
357 2560 prob = 128;
358 }
359
360 752640 ac_get(ac, gb, prob, &residual);
361 752640 v = ((predict >> 15) ^ residual) & 1;
362 752640 dsd[((i >> 3) * channels + ch) << 2] |= v << (7 - (i & 0x7 ));
363
364 752640 AV_WL64A(status + 8, (AV_RL64A(status + 8) << 1) | ((AV_RL64A(status) >> 63) & 1));
365 752640 AV_WL64A(status, (AV_RL64A(status) << 1) | v);
366 }
367 }
368
369 10 dsd:
370
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30 for (i = 0; i < channels; i++) {
371 20 ff_dsd2pcm_translate(&s->dsdctx[i], frame->nb_samples, 0,
372 20 frame->data[0] + i * 4,
373 20 channels * 4, pcm + i, channels);
374 }
375
376 10 *got_frame_ptr = 1;
377
378 10 return avpkt->size;
379 }
380
381 const AVCodec ff_dst_decoder = {
382 .name = "dst",
383 .long_name = NULL_IF_CONFIG_SMALL("DST (Digital Stream Transfer)"),
384 .type = AVMEDIA_TYPE_AUDIO,
385 .id = AV_CODEC_ID_DST,
386 .priv_data_size = sizeof(DSTContext),
387 .init = decode_init,
388 .decode = decode_frame,
389 .capabilities = AV_CODEC_CAP_DR1,
390 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
391 AV_SAMPLE_FMT_NONE },
392 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
393 };
394