2 * Copyright (C) 2009-2010 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. */
18 #include "buffer_tree.h"
21 #include "portable_io.h"
26 * How many FEC groups to store in memory.
28 * Packet reordering requires to keep more than one FEC group in memory because
29 * slices belonging to the next FEC group may arrive before the current FEC group
32 #define NUM_FEC_GROUPS 3
34 /** Data read from the header of a slice. */
36 /** Total number of slices in this group. */
37 uint8_t slices_per_group;
38 /** Number of slices needed to start decoding. */
39 uint8_t data_slices_per_group;
40 /** Size of the ogg vorbis/wma header (zero for mp3, aac). */
41 uint32_t audio_header_size;
42 /** Number of the FEC group this slice belongs to. */
44 /** Size of the data in this FEC group. */
46 /** Number of this slice in the group. */
48 /** Used data bytes of this slice. */
50 /** Non-zero if this group is the beginning of the stream. */
52 /** Non-zero if this stream embedds audio headers into fec groups. */
53 uint8_t header_stream;
57 * The status of one partially received FEC group.
60 /** The header read from the last slice. */
62 /** How many slices received so far. */
63 int num_received_slices;
64 /** The size of the \a idx and the \a data arrays below. */
66 /** Array of indices of the received slices. */
68 /** Content of the received slices. */
73 * Data private to the fecdec filter.
75 struct private_fecdec_data {
76 /** Used by the fec core code. */
77 struct fec_parms *fec;
78 /** Keeps track of what was received so far. */
79 struct fecdec_group groups[NUM_FEC_GROUPS];
80 /** Whether an audio file header was already received. */
82 /** Points to the first received group. */
83 struct fecdec_group *first_complete_group;
84 struct btr_pool *btrp;
87 /** Iterate over all fecdec groups. */
88 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
89 (g) < (d)->groups + NUM_FEC_GROUPS; (g)++)
91 static int group_complete(struct fecdec_group *fg)
93 return fg->num_received_slices >= fg->h.data_slices_per_group;
96 static int group_empty(struct fecdec_group *fg)
98 return fg->num_received_slices == 0;
101 static void clear_group(struct fecdec_group *fg)
105 for (i = 0; i < fg->num_slices; i++) {
115 memset(&fg->h, 0, sizeof(struct fec_header));
116 fg->num_received_slices = 0;
119 static int find_group(struct fec_header *h,
120 struct private_fecdec_data *pfd, struct fecdec_group **result)
122 struct fecdec_group *fg;
124 FOR_EACH_FECDEC_GROUP(fg, pfd) {
125 if (fg->h.group_num != h->group_num)
127 if (fg->num_received_slices == 0)
129 if (fg->h.slices_per_group != h->slices_per_group)
130 return -E_BAD_FEC_HEADER;
131 if (fg->h.data_slices_per_group != h->data_slices_per_group)
132 return -E_BAD_FEC_HEADER;
133 if (fg->h.group_bytes != h->group_bytes)
134 return -E_BAD_FEC_HEADER;
142 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
144 struct fecdec_group *fg;
146 FOR_EACH_FECDEC_GROUP(fg, pfd) {
147 if (fg->num_received_slices == 0)
153 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
155 struct fecdec_group *fg;
157 FOR_EACH_FECDEC_GROUP(fg, pfd) {
158 if (!group_complete(fg))
161 * Don't clear the first complete group if it has not yet been
164 if (fg == pfd->first_complete_group)
172 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
174 struct fecdec_group *fg, *oldest = NULL;
176 FOR_EACH_FECDEC_GROUP(fg, pfd) {
177 if (!oldest || oldest->h.group_num > fg->h.group_num)
180 if (!group_complete(oldest) && !group_empty(oldest))
181 PARA_WARNING_LOG("Clearing incomplete group %d "
182 "(contains %d slices)\n", oldest->h.group_num,
183 oldest->num_received_slices);
184 if (oldest == pfd->first_complete_group)
185 pfd->first_complete_group = NULL;
190 /* returns 1 if the group was found, 0 if not, negative on errors */
191 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
192 struct fecdec_group **result)
194 struct fecdec_group *fg;
195 int ret = find_group(h, pfd, &fg);
199 if (ret > 0) /* found group */
201 /* group not found */
202 fg = find_unused_group(pfd);
205 fg = try_to_free_group(pfd);
208 fg = free_oldest_group(pfd);
217 * returns 1 if slice was added, zero otherwise (because the group was already
218 * complete). In any case the number of received slices is being increased by
221 static int add_slice(char *buf, struct fecdec_group *fg)
225 if (group_complete(fg)) {
226 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
227 fg->h.group_num, fg->h.slice_num);
228 fg->num_received_slices++;
231 slice_num = fg->h.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_malloc(fg->num_slices * sizeof(unsigned char *));
236 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
238 r = fg->num_received_slices;
239 fg->idx[r] = slice_num;
240 fg->data[r] = para_malloc(fg->h.slice_bytes);
241 memcpy(fg->data[r], buf, fg->h.slice_bytes);
242 fg->num_received_slices++;
247 * The different states of a complete FEC group.
249 * Even if a FEC group has been received successfully, it probably can not be
250 * used right away because some streams (ogg, wma) need to receive an audio
251 * file header before decoding can start.
253 enum fec_group_usability {
254 /** Drop the group (because we did not receive the header yet). */
256 /** Use all data in the group. */
258 /** Use the group, but drop its audio file header. */
259 FEC_GROUP_USABLE_SKIP_HEADER,
260 /** Use the group, including its header. */
261 FEC_GROUP_USABLE_WITH_HEADER
264 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
265 struct private_fecdec_data *pfd)
267 struct fec_header *h = &fg->h;
269 if (!h->header_stream)
270 return FEC_GROUP_USABLE;
271 if (pfd->have_header) {
272 if (h->audio_header_size)
273 return FEC_GROUP_USABLE_SKIP_HEADER;
274 return FEC_GROUP_USABLE;
277 return FEC_GROUP_USABLE;
278 if (fg->h.audio_header_size)
279 return FEC_GROUP_USABLE_WITH_HEADER;
280 return FEC_GROUP_UNUSABLE;
283 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
285 int i, ret, sb = fg->h.slice_bytes;
286 size_t written, need;
287 struct private_fecdec_data *pfd = fn->private_data;
288 enum fec_group_usability u = group_is_usable(fg, pfd);
289 char *buf = NULL, *p;
291 if (u == FEC_GROUP_UNUSABLE) {
292 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
295 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
296 fg->h.data_slices_per_group);
297 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
300 pfd->have_header = 1;
302 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
303 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
305 PARA_DEBUG_LOG("skipping %d header slices\n", i);
307 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
308 fg->h.group_num, fg->h.group_bytes,
309 fg->h.data_slices_per_group * sb);
310 need = (fg->h.data_slices_per_group - i) * sb;
311 if (need > btr_pool_unused(pfd->btrp))
312 return -E_FECDEC_OVERRUN;
313 btr_pool_get_buffer(pfd->btrp, &buf);
315 if (u == FEC_GROUP_USABLE_WITH_HEADER) {
316 PARA_INFO_LOG("writing audio file header\n");
318 for (i = 0; i < fg->h.data_slices_per_group; i++) {
320 if (written >= fg->h.audio_header_size)
322 if (sb + written > fg->h.audio_header_size)
323 n = fg->h.audio_header_size - written;
324 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
330 for (; i < fg->h.data_slices_per_group; i++) {
332 if (n + written > fg->h.group_bytes)
333 n = fg->h.group_bytes - written;
334 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
342 * Read a fec header from a buffer.
344 * \param buf The buffer to write to.
345 * \param h The fec header to write.
347 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
351 if (len < FEC_HEADER_SIZE)
353 magic = read_u32(buf);
354 if (magic != FEC_MAGIC)
355 return -E_BAD_FEC_HEADER;
356 h->slices_per_group = read_u8(buf + 4);
357 h->data_slices_per_group = read_u8(buf + 5);
358 h->audio_header_size = read_u32(buf + 6);
360 h->group_num = read_u32(buf + 10);
361 h->group_bytes = read_u32(buf + 14);
363 h->slice_num = read_u8(buf + 18);
364 h->slice_bytes = read_u16(buf + 20);
365 h->bos = read_u8(buf + 22);
366 h->header_stream = read_u8(buf + 23);
367 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
368 return -E_FECDEC_EOF;
369 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
370 // h->group_num, h->slice_num, h->slices_per_group);
374 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
375 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
376 struct filter_node *fn)
378 struct fecdec_group *fg;
380 struct private_fecdec_data *pfd = fn->private_data;
382 if (h->slice_bytes > len) { /* can not use the thing, try to read more */
383 fn->min_iqs = h->slice_bytes + FEC_HEADER_SIZE;
386 ret = get_group(h, pfd, &fg);
389 if (!add_slice(buf, fg)) /* group already complete */
391 if (!group_complete(fg))
393 /* this slice completed the group */
396 /* it's either the first or the second complete group */
397 if (!pfd->first_complete_group) { /* it's the first group */
398 enum fec_group_usability u = group_is_usable(fg, pfd);
399 assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
400 if (u == FEC_GROUP_UNUSABLE) /* forget it */
402 pfd->first_complete_group = fg; /* remember it */
405 /* we have two complete groups, let's go */
406 k = h->data_slices_per_group;
407 n = h->slices_per_group;
408 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
409 ret = fec_new(k, n, &pfd->fec);
412 pfd->btrp = btr_pool_new("fecdec", 20 * k * h->slice_bytes);
413 /* decode and clear the first group */
414 ret = decode_group(pfd->first_complete_group, fn);
417 clear_group(pfd->first_complete_group);
418 pfd->first_complete_group = NULL;
420 ret = decode_group(fg, fn);
426 static void fecdec_close(struct filter_node *fn)
428 struct private_fecdec_data *pfd = fn->private_data;
429 struct fecdec_group *fg;
431 FOR_EACH_FECDEC_GROUP(fg, pfd)
434 btr_pool_free(pfd->btrp);
435 free(fn->private_data);
436 fn->private_data = NULL;
439 static void fecdec_post_select(__a_unused struct sched *s, struct task *t)
441 struct filter_node *fn = container_of(t, struct filter_node, task);
442 struct btr_node *btrn = fn->btrn;
449 ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
452 btr_merge(btrn, fn->min_iqs);
453 len = btr_next_buffer(btrn, &buf);
454 ret = read_fec_header(buf, len, &h);
457 ret = -E_BAD_SLICE_SIZE;
460 ret = -E_BAD_SLICE_NUM;
461 if (h.slice_num > h.slices_per_group)
463 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
465 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
468 btr_consume(btrn, FEC_HEADER_SIZE + h.slice_bytes);
473 btr_remove_node(btrn);
476 static void fecdec_open(struct filter_node *fn)
478 struct private_fecdec_data *pfd;
479 pfd = para_calloc(sizeof(*pfd));
480 fn->private_data = pfd;
481 fn->min_iqs = FEC_HEADER_SIZE;
485 * The init function of the fecdec filter.
487 * \param f Struct to initialize.
489 void fecdec_filter_init(struct filter *f)
491 f->close = fecdec_close;
492 f->open = fecdec_open;
493 f->pre_select = generic_filter_pre_select;
494 f->post_select = fecdec_post_select;