2 * Copyright (C) 2009-2011 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file fecdec_filter.c A filter that fec-decodes an audio stream. */
17 #include "buffer_tree.h"
20 #include "portable_io.h"
25 * How many FEC groups to store in memory.
27 * Packet reordering requires to keep more than one FEC group in memory because
28 * slices belonging to the next FEC group may arrive before the current FEC group
31 #define NUM_FEC_GROUPS 3
33 /** Data read from the header of a slice. */
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/wma header (zero for mp3, aac). */
40 uint32_t audio_header_size;
41 /** Number of the FEC group this slice belongs to. */
43 /** Size of the data in this FEC group. */
45 /** Number of this slice in the group. */
47 /** Used data bytes of this slice. */
49 /** Non-zero if this group is the beginning of the stream. */
51 /** Non-zero if this stream embedds audio headers into fec groups. */
52 uint8_t header_stream;
56 * The status of one partially received FEC group.
59 /** The header read from the last slice. */
61 /** How many slices received so far. */
62 int num_received_slices;
63 /** Bitmap of received slices. */
64 uint8_t received_slices[32];
65 /** The size of the \a idx and the \a data arrays below. */
67 /** Array of indices of the received slices. */
69 /** Content of the received slices. */
74 * Data private to the fecdec filter.
76 struct private_fecdec_data {
77 /** Used by the fec core code. */
78 struct fec_parms *fec;
79 /** Keeps track of what was received so far. */
80 struct fecdec_group groups[NUM_FEC_GROUPS];
81 /** Whether an audio file header was already received. */
83 /** Points to the first received group. */
84 struct fecdec_group *first_complete_group;
85 struct btr_pool *btrp;
88 /** Iterate over all fecdec groups. */
89 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
90 (g) < (d)->groups + NUM_FEC_GROUPS; (g)++)
92 static int group_complete(struct fecdec_group *fg)
94 return fg->num_received_slices >= fg->h.data_slices_per_group;
97 static int group_empty(struct fecdec_group *fg)
99 return fg->num_received_slices == 0;
102 static void clear_group(struct fecdec_group *fg)
106 for (i = 0; i < fg->num_slices; i++)
110 memset(fg, 0, sizeof(*fg));
113 static int find_group(struct fec_header *h,
114 struct private_fecdec_data *pfd, struct fecdec_group **result)
116 struct fecdec_group *fg;
118 FOR_EACH_FECDEC_GROUP(fg, pfd) {
119 if (fg->h.group_num != h->group_num)
121 if (fg->num_received_slices == 0)
123 if (fg->h.slices_per_group != h->slices_per_group)
124 return -E_BAD_FEC_HEADER;
125 if (fg->h.data_slices_per_group != h->data_slices_per_group)
126 return -E_BAD_FEC_HEADER;
127 if (fg->h.group_bytes != h->group_bytes)
128 return -E_BAD_FEC_HEADER;
136 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
138 struct fecdec_group *fg;
140 FOR_EACH_FECDEC_GROUP(fg, pfd) {
141 if (fg->num_received_slices == 0)
147 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
149 struct fecdec_group *fg;
151 FOR_EACH_FECDEC_GROUP(fg, pfd) {
152 if (!group_complete(fg))
155 * Don't clear the first complete group if it has not yet been
158 if (fg == pfd->first_complete_group)
166 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
168 struct fecdec_group *fg, *oldest = NULL;
170 FOR_EACH_FECDEC_GROUP(fg, pfd) {
171 if (!oldest || oldest->h.group_num > fg->h.group_num)
174 if (!group_complete(oldest) && !group_empty(oldest))
175 PARA_WARNING_LOG("Clearing incomplete group %d "
176 "(contains %d slices)\n", oldest->h.group_num,
177 oldest->num_received_slices);
178 if (oldest == pfd->first_complete_group)
179 pfd->first_complete_group = NULL;
184 /* returns 1 if the group was found, 0 if not, negative on errors */
185 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
186 struct fecdec_group **result)
188 struct fecdec_group *fg;
189 int ret = find_group(h, pfd, &fg);
193 if (ret > 0) /* found group */
195 /* group not found */
196 fg = find_unused_group(pfd);
199 fg = try_to_free_group(pfd);
202 fg = free_oldest_group(pfd);
210 static bool test_and_set_slice_bit(struct fecdec_group *fg, uint8_t slice_num)
212 uint8_t *p = fg->received_slices + slice_num / 8, old = *p;
214 *p |= 1 << (slice_num % 8);
219 * returns 1 if slice was added, zero otherwise (because the group was already
220 * complete or a slice has been received twice).
222 static int add_slice(char *buf, struct fecdec_group *fg)
225 uint8_t slice_num = fg->h.slice_num;
227 if (group_complete(fg)) {
228 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
229 fg->h.group_num, slice_num);
232 if (fg->num_slices == 0) {
233 fg->num_slices = fg->h.slices_per_group;
234 fg->idx = para_malloc(fg->num_slices * sizeof(int));
235 fg->data = para_calloc(fg->num_slices * sizeof(unsigned char *));
237 r = fg->num_received_slices;
238 /* Check if we already have this slice. */
239 if (test_and_set_slice_bit(fg, slice_num)) {
240 PARA_INFO_LOG("ignoring duplicate slice %d:%d\n", fg->h.group_num,
244 fg->idx[r] = slice_num;
245 fg->data[r] = para_malloc(fg->h.slice_bytes);
246 memcpy(fg->data[r], buf, fg->h.slice_bytes);
247 fg->num_received_slices++;
252 * The different states of a complete FEC group.
254 * Even if a FEC group has been received successfully, it probably can not be
255 * used right away because some streams (ogg, wma) need to receive an audio
256 * file header before decoding can start.
258 enum fec_group_usability {
259 /** Drop the group (because we did not receive the header yet). */
261 /** Use all data in the group. */
263 /** Use the group, but drop its audio file header. */
264 FEC_GROUP_USABLE_SKIP_HEADER,
265 /** Use the group, including its header. */
266 FEC_GROUP_USABLE_WITH_HEADER
269 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
270 struct private_fecdec_data *pfd)
272 struct fec_header *h = &fg->h;
274 if (!h->header_stream)
275 return FEC_GROUP_USABLE;
276 if (pfd->have_header) {
277 if (h->audio_header_size)
278 return FEC_GROUP_USABLE_SKIP_HEADER;
279 return FEC_GROUP_USABLE;
282 return FEC_GROUP_USABLE;
283 if (fg->h.audio_header_size)
284 return FEC_GROUP_USABLE_WITH_HEADER;
285 return FEC_GROUP_UNUSABLE;
288 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
290 int i, ret, sb = fg->h.slice_bytes;
291 size_t written, need;
292 struct private_fecdec_data *pfd = fn->private_data;
293 enum fec_group_usability u = group_is_usable(fg, pfd);
294 char *buf = NULL, *p;
296 if (u == FEC_GROUP_UNUSABLE) {
297 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
300 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
301 fg->h.data_slices_per_group);
302 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
305 pfd->have_header = 1;
307 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
308 i = DIV_ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes);
309 PARA_DEBUG_LOG("skipping %d header slices\n", i);
311 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
312 fg->h.group_num, fg->h.group_bytes,
313 fg->h.data_slices_per_group * sb);
314 need = (fg->h.data_slices_per_group - i) * sb;
315 if (need > btr_pool_unused(pfd->btrp))
316 return -E_FECDEC_OVERRUN;
317 btr_pool_get_buffer(pfd->btrp, &buf);
319 if (u == FEC_GROUP_USABLE_WITH_HEADER) {
320 PARA_INFO_LOG("writing audio file header\n");
322 for (i = 0; i < fg->h.data_slices_per_group; i++) {
324 if (written >= fg->h.audio_header_size)
326 if (sb + written > fg->h.audio_header_size)
327 n = fg->h.audio_header_size - written;
328 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
334 for (; i < fg->h.data_slices_per_group; i++) {
336 if (n + written > fg->h.group_bytes)
337 n = fg->h.group_bytes - written;
338 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
346 * Read a fec header from a buffer.
348 * \param buf The buffer to write to.
349 * \param h The fec header to write.
351 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
355 if (len < FEC_HEADER_SIZE)
357 magic = read_u32(buf);
358 if (magic != FEC_MAGIC)
359 return -E_BAD_FEC_HEADER;
360 h->slices_per_group = read_u8(buf + 4);
361 h->data_slices_per_group = read_u8(buf + 5);
362 h->audio_header_size = read_u32(buf + 6);
364 h->group_num = read_u32(buf + 10);
365 h->group_bytes = read_u32(buf + 14);
367 h->slice_num = read_u8(buf + 18);
368 h->slice_bytes = read_u16(buf + 20);
369 h->bos = read_u8(buf + 22);
370 h->header_stream = read_u8(buf + 23);
371 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
372 return -E_FECDEC_EOF;
373 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
374 // h->group_num, h->slice_num, h->slices_per_group);
378 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
379 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
380 struct filter_node *fn)
382 struct fecdec_group *fg;
384 struct private_fecdec_data *pfd = fn->private_data;
386 if (h->slice_bytes > len) { /* can not use the thing, try to read more */
387 fn->min_iqs = h->slice_bytes + FEC_HEADER_SIZE;
390 ret = get_group(h, pfd, &fg);
393 if (!add_slice(buf, fg)) /* group already complete */
395 if (!group_complete(fg))
397 /* this slice completed the group */
400 /* it's either the first or the second complete group */
401 if (!pfd->first_complete_group) { /* it's the first group */
402 enum fec_group_usability u = group_is_usable(fg, pfd);
403 assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
404 if (u == FEC_GROUP_UNUSABLE) /* forget it */
406 pfd->first_complete_group = fg; /* remember it */
409 /* we have two complete groups, let's go */
410 k = h->data_slices_per_group;
411 n = h->slices_per_group;
412 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
413 ret = fec_new(k, n, &pfd->fec);
416 pfd->btrp = btr_pool_new("fecdec", 64 * 1024);
417 /* decode and clear the first group */
418 ret = decode_group(pfd->first_complete_group, fn);
421 clear_group(pfd->first_complete_group);
422 pfd->first_complete_group = NULL;
424 ret = decode_group(fg, fn);
430 static void fecdec_close(struct filter_node *fn)
432 struct private_fecdec_data *pfd = fn->private_data;
433 struct fecdec_group *fg;
435 FOR_EACH_FECDEC_GROUP(fg, pfd)
438 btr_pool_free(pfd->btrp);
439 free(fn->private_data);
440 fn->private_data = NULL;
443 static void fecdec_post_select(__a_unused struct sched *s, struct task *t)
445 struct filter_node *fn = container_of(t, struct filter_node, task);
446 struct btr_node *btrn = fn->btrn;
453 ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
456 btr_merge(btrn, fn->min_iqs);
457 len = btr_next_buffer(btrn, &buf);
458 ret = read_fec_header(buf, len, &h);
461 ret = -E_BAD_SLICE_SIZE;
464 ret = -E_BAD_SLICE_NUM;
465 if (h.slice_num > h.slices_per_group)
467 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
469 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
472 btr_consume(btrn, FEC_HEADER_SIZE + h.slice_bytes);
477 btr_remove_node(btrn);
480 static void fecdec_open(struct filter_node *fn)
482 struct private_fecdec_data *pfd;
483 pfd = para_calloc(sizeof(*pfd));
484 fn->private_data = pfd;
485 fn->min_iqs = FEC_HEADER_SIZE;
489 * The init function of the fecdec filter.
491 * \param f Struct to initialize.
493 void fecdec_filter_init(struct filter *f)
495 f->close = fecdec_close;
496 f->open = fecdec_open;
497 f->pre_select = generic_filter_pre_select;
498 f->post_select = fecdec_post_select;