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path: root/libavcodec/dca_parser.c (plain)
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1/*
2 * DCA parser
3 * Copyright (C) 2004 Gildas Bazin
4 * Copyright (C) 2004 Benjamin Zores
5 * Copyright (C) 2006 Benjamin Larsson
6 * Copyright (C) 2007 Konstantin Shishkov
7 *
8 * This file is part of FFmpeg.
9 *
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#include "dca.h"
26#include "dca_exss.h"
27#include "dca_syncwords.h"
28#include "get_bits.h"
29#include "parser.h"
30
31typedef struct DCAParseContext {
32 ParseContext pc;
33 uint32_t lastmarker;
34 int size;
35 int framesize;
36 unsigned int startpos;
37 DCAExssParser exss;
38 unsigned int sr_code;
39} DCAParseContext;
40
41#define IS_CORE_MARKER(state) \
42 (((state & 0xFFFFFFFFF0FF) == (((uint64_t)DCA_SYNCWORD_CORE_14B_LE << 16) | 0xF007)) || \
43 ((state & 0xFFFFFFFFFFF0) == (((uint64_t)DCA_SYNCWORD_CORE_14B_BE << 16) | 0x07F0)) || \
44 ((state & 0xFFFFFFFF00FC) == (((uint64_t)DCA_SYNCWORD_CORE_LE << 16) | 0x00FC)) || \
45 ((state & 0xFFFFFFFFFC00) == (((uint64_t)DCA_SYNCWORD_CORE_BE << 16) | 0xFC00)))
46
47#define IS_EXSS_MARKER(state) ((state & 0xFFFFFFFF) == DCA_SYNCWORD_SUBSTREAM)
48
49#define IS_MARKER(state) (IS_CORE_MARKER(state) || IS_EXSS_MARKER(state))
50
51#define CORE_MARKER(state) ((state >> 16) & 0xFFFFFFFF)
52#define EXSS_MARKER(state) (state & 0xFFFFFFFF)
53
54#define STATE_LE(state) (((state & 0xFF00FF00) >> 8) | ((state & 0x00FF00FF) << 8))
55#define STATE_14(state) (((state & 0x3FFF0000) >> 8) | ((state & 0x00003FFF) >> 6))
56
57#define CORE_FRAMESIZE(state) (((state >> 4) & 0x3FFF) + 1)
58#define EXSS_FRAMESIZE(state) ((state & 0x2000000000) ? \
59 ((state >> 5) & 0xFFFFF) + 1 : \
60 ((state >> 13) & 0x0FFFF) + 1)
61
62/**
63 * Find the end of the current frame in the bitstream.
64 * @return the position of the first byte of the next frame, or -1
65 */
66static int dca_find_frame_end(DCAParseContext *pc1, const uint8_t *buf,
67 int buf_size)
68{
69 int start_found, size, i;
70 uint64_t state;
71 ParseContext *pc = &pc1->pc;
72
73 start_found = pc->frame_start_found;
74 state = pc->state64;
75 size = pc1->size;
76
77 i = 0;
78 if (!start_found) {
79 for (; i < buf_size; i++) {
80 size++;
81 state = (state << 8) | buf[i];
82
83 if (IS_MARKER(state) &&
84 (!pc1->lastmarker ||
85 pc1->lastmarker == CORE_MARKER(state) ||
86 pc1->lastmarker == DCA_SYNCWORD_SUBSTREAM)) {
87 if (!pc1->lastmarker)
88 pc1->startpos = IS_EXSS_MARKER(state) ? size - 4 : size - 6;
89
90 if (IS_EXSS_MARKER(state))
91 pc1->lastmarker = EXSS_MARKER(state);
92 else
93 pc1->lastmarker = CORE_MARKER(state);
94
95 start_found = 1;
96 size = 0;
97
98 i++;
99 break;
100 }
101 }
102 }
103
104 if (start_found) {
105 for (; i < buf_size; i++) {
106 size++;
107 state = (state << 8) | buf[i];
108
109 if (start_found == 1) {
110 switch (pc1->lastmarker) {
111 case DCA_SYNCWORD_CORE_BE:
112 if (size == 2) {
113 pc1->framesize = CORE_FRAMESIZE(state);
114 start_found = 2;
115 }
116 break;
117 case DCA_SYNCWORD_CORE_LE:
118 if (size == 2) {
119 pc1->framesize = CORE_FRAMESIZE(STATE_LE(state));
120 start_found = 4;
121 }
122 break;
123 case DCA_SYNCWORD_CORE_14B_BE:
124 if (size == 4) {
125 pc1->framesize = CORE_FRAMESIZE(STATE_14(state)) * 8 / 14 * 2;
126 start_found = 4;
127 }
128 break;
129 case DCA_SYNCWORD_CORE_14B_LE:
130 if (size == 4) {
131 pc1->framesize = CORE_FRAMESIZE(STATE_14(STATE_LE(state))) * 8 / 14 * 2;
132 start_found = 4;
133 }
134 break;
135 case DCA_SYNCWORD_SUBSTREAM:
136 if (size == 6) {
137 pc1->framesize = EXSS_FRAMESIZE(state);
138 start_found = 4;
139 }
140 break;
141 default:
142 av_assert0(0);
143 }
144 continue;
145 }
146
147 if (start_found == 2 && IS_EXSS_MARKER(state) &&
148 pc1->framesize <= size + 2) {
149 pc1->framesize = size + 2;
150 start_found = 3;
151 continue;
152 }
153
154 if (start_found == 3) {
155 if (size == pc1->framesize + 4) {
156 pc1->framesize += EXSS_FRAMESIZE(state);
157 start_found = 4;
158 }
159 continue;
160 }
161
162 if (pc1->framesize > size)
163 continue;
164
165 if (IS_MARKER(state) &&
166 (pc1->lastmarker == CORE_MARKER(state) ||
167 pc1->lastmarker == DCA_SYNCWORD_SUBSTREAM)) {
168 pc->frame_start_found = 0;
169 pc->state64 = -1;
170 pc1->size = 0;
171 return IS_EXSS_MARKER(state) ? i - 3 : i - 5;
172 }
173 }
174 }
175
176 pc->frame_start_found = start_found;
177 pc->state64 = state;
178 pc1->size = size;
179 return END_NOT_FOUND;
180}
181
182static av_cold int dca_parse_init(AVCodecParserContext *s)
183{
184 DCAParseContext *pc1 = s->priv_data;
185
186 pc1->lastmarker = 0;
187 pc1->sr_code = -1;
188 return 0;
189}
190
191static int dca_parse_params(DCAParseContext *pc1, const uint8_t *buf,
192 int buf_size, int *duration, int *sample_rate)
193{
194 GetBitContext gb;
195 uint8_t hdr[12 + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 };
196 int ret, sample_blocks;
197
198 if (buf_size < 12)
199 return AVERROR_INVALIDDATA;
200
201 if (AV_RB32(buf) == DCA_SYNCWORD_SUBSTREAM) {
202 DCAExssAsset *asset = &pc1->exss.assets[0];
203
204 if ((ret = ff_dca_exss_parse(&pc1->exss, buf, buf_size)) < 0)
205 return ret;
206
207 if (asset->extension_mask & DCA_EXSS_LBR) {
208 if ((ret = init_get_bits8(&gb, buf + asset->lbr_offset, asset->lbr_size)) < 0)
209 return ret;
210
211 if (get_bits_long(&gb, 32) != DCA_SYNCWORD_LBR)
212 return AVERROR_INVALIDDATA;
213
214 switch (get_bits(&gb, 8)) {
215 case 2:
216 pc1->sr_code = get_bits(&gb, 8);
217 case 1:
218 break;
219 default:
220 return AVERROR_INVALIDDATA;
221 }
222
223 if (pc1->sr_code >= FF_ARRAY_ELEMS(ff_dca_sampling_freqs))
224 return AVERROR_INVALIDDATA;
225
226 *sample_rate = ff_dca_sampling_freqs[pc1->sr_code];
227 *duration = 1024 << ff_dca_freq_ranges[pc1->sr_code];
228 return 0;
229 }
230
231 if (asset->extension_mask & DCA_EXSS_XLL) {
232 int nsamples_log2;
233
234 if ((ret = init_get_bits8(&gb, buf + asset->xll_offset, asset->xll_size)) < 0)
235 return ret;
236
237 if (get_bits_long(&gb, 32) != DCA_SYNCWORD_XLL)
238 return AVERROR_INVALIDDATA;
239
240 if (get_bits(&gb, 4))
241 return AVERROR_INVALIDDATA;
242
243 skip_bits(&gb, 8);
244 skip_bits_long(&gb, get_bits(&gb, 5) + 1);
245 skip_bits(&gb, 4);
246 nsamples_log2 = get_bits(&gb, 4) + get_bits(&gb, 4);
247 if (nsamples_log2 > 24)
248 return AVERROR_INVALIDDATA;
249
250 *sample_rate = asset->max_sample_rate;
251 *duration = (1 + (*sample_rate > 96000)) << nsamples_log2;
252 return 0;
253 }
254
255 return AVERROR_INVALIDDATA;
256 }
257
258 if ((ret = avpriv_dca_convert_bitstream(buf, 12, hdr, 12)) < 0)
259 return ret;
260
261 init_get_bits(&gb, hdr, 96);
262
263 skip_bits_long(&gb, 39);
264 sample_blocks = get_bits(&gb, 7) + 1;
265 if (sample_blocks < 8)
266 return AVERROR_INVALIDDATA;
267 *duration = 256 * (sample_blocks / 8);
268
269 skip_bits(&gb, 20);
270 *sample_rate = avpriv_dca_sample_rates[get_bits(&gb, 4)];
271 if (*sample_rate == 0)
272 return AVERROR_INVALIDDATA;
273
274 return 0;
275}
276
277static int dca_parse(AVCodecParserContext *s, AVCodecContext *avctx,
278 const uint8_t **poutbuf, int *poutbuf_size,
279 const uint8_t *buf, int buf_size)
280{
281 DCAParseContext *pc1 = s->priv_data;
282 ParseContext *pc = &pc1->pc;
283 int next, duration, sample_rate;
284
285 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
286 next = buf_size;
287 } else {
288 next = dca_find_frame_end(pc1, buf, buf_size);
289
290 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
291 *poutbuf = NULL;
292 *poutbuf_size = 0;
293 return buf_size;
294 }
295
296 /* skip initial padding */
297 if (buf_size > pc1->startpos) {
298 buf += pc1->startpos;
299 buf_size -= pc1->startpos;
300 }
301 pc1->startpos = 0;
302 }
303
304 /* read the duration and sample rate from the frame header */
305 if (!dca_parse_params(pc1, buf, buf_size, &duration, &sample_rate)) {
306 if (!avctx->sample_rate)
307 avctx->sample_rate = sample_rate;
308 s->duration = av_rescale(duration, avctx->sample_rate, sample_rate);
309 } else
310 s->duration = 0;
311
312 *poutbuf = buf;
313 *poutbuf_size = buf_size;
314 return next;
315}
316
317AVCodecParser ff_dca_parser = {
318 .codec_ids = { AV_CODEC_ID_DTS },
319 .priv_data_size = sizeof(DCAParseContext),
320 .parser_init = dca_parse_init,
321 .parser_parse = dca_parse,
322 .parser_close = ff_parse_close,
323};
324
generated by cgit at 2024-05-17 08:25:26 (GMT)