bc5300627dbdfb7a1ab1bf37f0ac5aa681dbd4a2
[paraslash.git] / fecdec_filter.c
1 /*
2 * Copyright (C) 2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file fecdec_filter.c A filter fec-decodes an audio stream. */
8
9 #include <dirent.h>
10 #include "para.h"
11 #include "error.h"
12 #include "list.h"
13 #include "sched.h"
14 #include "ggo.h"
15 #include "filter.h"
16 #include "string.h"
17 #include "portable_io.h"
18 #include "fec.h"
19 #include "fd.h"
20
21 /**
22 * How many FEC groups to store in memory.
23 *
24 * Packet reordering requires to keep more than one FEC group in memory because
25 * slices belonging to the next FEC group may arrive before the current FEC group
26 * is complete.
27 */
28 #define NUM_FEC_GROUPS 3
29
30 /** Size of the output buffer of the fecdec filter. */
31 #define FECDEC_OUTBUF_SIZE (1024 * 1024) /* FIXME: This has to depend on the fec params */
32
33 /** Data read from the header of a slice. */
34 struct fec_header {
35 /** Total number of slices in this group. */
36 uint8_t slices_per_group;
37 /** Number of slices needed to start decoding. */
38 uint8_t data_slices_per_group;
39 /** Size of the ogg vorbis header (zero for mp3, aac). */
40 uint32_t audio_header_size;
41 /** Number of the FEC group this slice belongs to. */
42 uint32_t group_num;
43 /** Size of the data in this FEC group. */
44 uint32_t group_bytes;
45 /** Number of this slice in the group. */
46 uint8_t slice_num;
47 /** Used data bytes of this slice. */
48 uint16_t slice_bytes;
49 /** Non-zero if this group is the beginning of the stream. */
50 uint8_t bos;
51 /** Non-zero if this stream embedds audio headers into fec groups. */
52 uint8_t header_stream;
53 };
54
55 /**
56 * The status of one partially received FEC group.
57 */
58 struct fecdec_group {
59 /** The header read from the last slice. */
60 struct fec_header h;
61 /** How many slices received so far. */
62 int num_received_slices;
63 /** The size of the \a idx and the \a data arrays below. */
64 int num_slices;
65 /** Array of indices of the received slices. */
66 int *idx;
67 /** Content of the received slices. */
68 unsigned char **data;
69 };
70
71 /**
72 * Data private to the fecdec filter.
73 */
74 struct private_fecdec_data {
75 /** Used by the fec core code. */
76 struct fec_parms *fec;
77 /** Keeps track of what was received so far. */
78 struct fecdec_group groups[NUM_FEC_GROUPS];
79 int have_header;
80 };
81
82 /** Iterate over all fecdec groups. */
83 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
84 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
85
86 static int group_complete(struct fecdec_group *fg)
87 {
88 return fg->num_received_slices >= fg->h.data_slices_per_group;
89 }
90
91 static int group_empty(struct fecdec_group *fg)
92 {
93 return fg->num_received_slices == 0;
94 }
95
96 static void clear_group(struct fecdec_group *fg)
97 {
98 int i;
99
100 for (i = 0; i < fg->num_slices; i++) {
101 free(fg->data[i]);
102 fg->data[i] = NULL;
103 fg->idx[i] = -1;
104 }
105 free(fg->data);
106 free(fg->idx);
107 fg->num_slices = 0;
108 memset(&fg->h, 0, sizeof(struct fec_header));
109 fg->num_received_slices = 0;
110 }
111
112 static int find_group(struct fec_header *h,
113 struct private_fecdec_data *pfd, struct fecdec_group **result)
114 {
115 struct fecdec_group *fg;
116
117 FOR_EACH_FECDEC_GROUP(fg, pfd) {
118 if (fg->h.group_num != h->group_num)
119 continue;
120 if (fg->h.slices_per_group != h->slices_per_group)
121 continue;
122 if (fg->h.data_slices_per_group != h->data_slices_per_group)
123 continue;
124 *result = fg;
125 return 1;
126 }
127 return 0;
128 }
129
130 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
131 {
132 struct fecdec_group *fg;
133
134 FOR_EACH_FECDEC_GROUP(fg, pfd) {
135 if (fg->num_received_slices == 0)
136 return fg;
137 }
138 return NULL;
139 }
140
141 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
142 {
143 struct fecdec_group *fg;
144
145 FOR_EACH_FECDEC_GROUP(fg, pfd) {
146 if (!group_complete(fg))
147 continue;
148 clear_group(fg);
149 return fg;
150 }
151 return NULL;
152 }
153
154 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
155 {
156 struct fecdec_group *fg, *oldest = NULL;
157
158 FOR_EACH_FECDEC_GROUP(fg, pfd) {
159 if (!oldest || oldest->h.group_num > fg->h.group_num)
160 oldest = fg;
161 }
162 if (!group_complete(oldest) && !group_empty(oldest))
163 PARA_WARNING_LOG("Clearing incomplete group %d "
164 "(contains %d slices)\n", fg->h.group_num,
165 fg->num_received_slices);
166 clear_group(oldest);
167 return oldest;
168 }
169
170 /* returns 1 if the group was found, 0 if not, negative on errors */
171 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
172 struct fecdec_group **result)
173 {
174 struct fecdec_group *fg;
175 int ret = find_group(h, pfd, &fg);
176
177 if (ret < 0)
178 return ret;
179 if (ret > 0) /* found group */
180 goto success;
181 /* group not found */
182 fg = find_unused_group(pfd);
183 if (fg)
184 goto success;
185 fg = try_to_free_group(pfd);
186 if (fg)
187 goto success;
188 fg = free_oldest_group(pfd);
189 ret = 0;
190 success:
191 fg->h = *h;
192 *result = fg;
193 return ret;
194 }
195
196 /*
197 * returns 1 if slice was added, zero otherwise (because the group was already
198 * complete). In any case the number of received slices is being increased by
199 * one.
200 */
201 static int add_slice(char *buf, struct fecdec_group *fg)
202 {
203 int r, slice_num;
204
205 if (group_complete(fg)) {
206 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
207 fg->h.slice_num);
208 fg->num_received_slices++;
209 return 0;
210 }
211 slice_num = fg->h.slice_num;
212 if (fg->num_slices == 0) {
213 fg->num_slices = fg->h.slices_per_group;
214 fg->idx = malloc(fg->num_slices * sizeof(int));
215 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
216 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
217 }
218 r = fg->num_received_slices;
219 fg->idx[r] = slice_num;
220 fg->data[r] = malloc(fg->h.slice_bytes);
221 memcpy(fg->data[r], buf, fg->h.slice_bytes);
222 fg->num_received_slices++;
223 return 1;
224 }
225
226 enum fec_group_usability {
227 FEC_GROUP_UNUSABLE,
228 FEC_GROUP_USABLE,
229 FEC_GROUP_USABLE_SKIP_HEADER,
230 };
231
232 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
233 struct private_fecdec_data *pfd)
234 {
235 struct fec_header *h = &fg->h;
236
237 if (!h->header_stream)
238 return FEC_GROUP_USABLE;
239 if (pfd->have_header) {
240 if (h->audio_header_size)
241 return FEC_GROUP_USABLE_SKIP_HEADER;
242 return FEC_GROUP_USABLE;
243 }
244 if (fg->h.bos)
245 return FEC_GROUP_USABLE;
246 if (fg->h.audio_header_size)
247 return FEC_GROUP_USABLE;
248 return FEC_GROUP_UNUSABLE;
249 }
250
251 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
252 {
253 int i, ret, sb = fg->h.slice_bytes;
254 size_t written = 0;
255 struct private_fecdec_data *pfd = fn->private_data;
256 enum fec_group_usability u = group_is_usable(fg, pfd);
257
258 if (u == FEC_GROUP_UNUSABLE) {
259 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
260 return 0;
261 }
262 PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
263 fg->h.data_slices_per_group);
264 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
265 if (ret < 0)
266 return ret;
267 pfd->have_header = 1;
268 i = 0;
269 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
270 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
271 / fg->h.slice_bytes;
272 PARA_DEBUG_LOG("skipping %d header slices\n", i);
273 }
274 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
275 fg->h.group_num, fg->h.group_bytes,
276 fg->h.data_slices_per_group * sb);
277 for (; i < fg->h.data_slices_per_group; i++) {
278 size_t n = sb;
279 if (n + written > fg->h.group_bytes)
280 n = fg->h.group_bytes - written;
281 if (fn->loaded + n > fn->bufsize)
282 return -E_FECDEC_OVERRUN;
283 memcpy(fn->buf + fn->loaded, fg->data[i], n);
284 fn->loaded += n;
285 written += n;
286 }
287 return 0;
288 }
289
290 /**
291 * Read a fec header from a buffer.
292 *
293 * \param buf The buffer to write to.
294 * \param h The fec header to write.
295 */
296 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
297 {
298 uint32_t magic;
299
300 if (len < FEC_HEADER_SIZE)
301 return 0;
302 magic = read_u32(buf);
303 if (magic != FEC_MAGIC)
304 return -E_BAD_FEC_HEADER;
305 h->slices_per_group = read_u8(buf + 4);
306 h->data_slices_per_group = read_u8(buf + 5);
307 h->audio_header_size = read_u32(buf + 6);
308
309 h->group_num = read_u32(buf + 10);
310 h->group_bytes = read_u32(buf + 14);
311
312 h->slice_num = read_u8(buf + 18);
313 h->slice_bytes = read_u16(buf + 20);
314 h->bos = read_u8(buf + 22);
315 h->header_stream = read_u8(buf + 23);
316 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
317 return -E_FECDEC_EOF;
318 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
319 // h->group_num, h->slice_num, h->slices_per_group);
320 return 1;
321 }
322
323 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
324 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
325 struct filter_node *fn)
326 {
327 struct fecdec_group *fg;
328 int ret;
329 struct private_fecdec_data *pfd = fn->private_data;
330
331 if (h->slice_bytes > len) /* can not use the thing, try to read more */
332 return 0;
333 ret = get_group(h, pfd, &fg);
334 if (ret < 0)
335 return ret;
336 if (!add_slice(buf, fg))
337 return 1;
338 if (group_complete(fg)) {
339 if (!pfd->fec) {
340 int k = h->data_slices_per_group, n = h->slices_per_group;
341 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
342 ret = fec_new(k, n, &pfd->fec);
343 if (ret < 0)
344 return ret;
345 }
346 ret = decode_group(fg, fn);
347 if (ret < 0)
348 return ret;
349 }
350 return 1;
351 }
352
353 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
354 {
355 int ret;
356 struct fec_header h;
357
358 ret = read_fec_header(buf, len, &h);
359 if (ret <= 0)
360 return ret;
361 if (!h.slice_bytes || h.slice_bytes > fn->bufsize)
362 return -E_BAD_SLICE_SIZE;
363 if (h.slice_num > h.slices_per_group)
364 return -E_BAD_SLICE_NUM;
365 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
366 &h, fn);
367 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
368 if (ret <= 0)
369 return ret;
370 return FEC_HEADER_SIZE + h.slice_bytes;
371 }
372
373 static void fecdec_close(struct filter_node *fn)
374 {
375 struct private_fecdec_data *pfd = fn->private_data;
376 struct fecdec_group *fg;
377
378 FOR_EACH_FECDEC_GROUP(fg, pfd)
379 clear_group(fg);
380 free(fn->buf);
381 fn->buf = NULL;
382 fec_free(pfd->fec);
383 free(fn->private_data);
384 fn->private_data = NULL;
385 }
386
387 static void fecdec_open(struct filter_node *fn)
388 {
389 fn->bufsize = FECDEC_OUTBUF_SIZE;
390 fn->buf = para_malloc(fn->bufsize);
391 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
392 fn->loaded = 0;
393 }
394
395 /**
396 * The init function of the fecdec filter.
397 *
398 * \param f struct to initialize.
399 */
400 void fecdec_filter_init(struct filter *f)
401 {
402 f->convert = fecdec;
403 f->close = fecdec_close;
404 f->open = fecdec_open;
405 }