2 * Copyright (C) 2009 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 /** Default size of the output buffer of the fecdec filter. */
35 #define FECDEC_DEFAULT_OUTBUF_SIZE (3 * 1024)
36 /** Maximal size of the output buffer of the fecdec filter. */
37 #define FECDEC_MAX_OUTBUF_SIZE (1024 * 1024)
39 /** Data read from the header of a slice. */
41 /** Total number of slices in this group. */
42 uint8_t slices_per_group;
43 /** Number of slices needed to start decoding. */
44 uint8_t data_slices_per_group;
45 /** Size of the ogg vorbis/wma header (zero for mp3, aac). */
46 uint32_t audio_header_size;
47 /** Number of the FEC group this slice belongs to. */
49 /** Size of the data in this FEC group. */
51 /** Number of this slice in the group. */
53 /** Used data bytes of this slice. */
55 /** Non-zero if this group is the beginning of the stream. */
57 /** Non-zero if this stream embedds audio headers into fec groups. */
58 uint8_t header_stream;
62 * The status of one partially received FEC group.
65 /** The header read from the last slice. */
67 /** How many slices received so far. */
68 int num_received_slices;
69 /** The size of the \a idx and the \a data arrays below. */
71 /** Array of indices of the received slices. */
73 /** Content of the received slices. */
78 * Data private to the fecdec filter.
80 struct private_fecdec_data {
81 /** Used by the fec core code. */
82 struct fec_parms *fec;
83 /** Keeps track of what was received so far. */
84 struct fecdec_group groups[NUM_FEC_GROUPS];
85 /** Whether an audio file header was already received. */
87 /** Points to the first received group. */
88 struct fecdec_group *first_complete_group;
91 /** Iterate over all fecdec groups. */
92 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
93 (g) < (d)->groups + NUM_FEC_GROUPS; (g)++)
95 static int group_complete(struct fecdec_group *fg)
97 return fg->num_received_slices >= fg->h.data_slices_per_group;
100 static int group_empty(struct fecdec_group *fg)
102 return fg->num_received_slices == 0;
105 static void clear_group(struct fecdec_group *fg)
109 for (i = 0; i < fg->num_slices; i++) {
119 memset(&fg->h, 0, sizeof(struct fec_header));
120 fg->num_received_slices = 0;
123 static int find_group(struct fec_header *h,
124 struct private_fecdec_data *pfd, struct fecdec_group **result)
126 struct fecdec_group *fg;
128 FOR_EACH_FECDEC_GROUP(fg, pfd) {
129 if (fg->h.group_num != h->group_num)
131 if (fg->num_received_slices == 0)
133 if (fg->h.slices_per_group != h->slices_per_group)
134 return -E_BAD_FEC_HEADER;
135 if (fg->h.data_slices_per_group != h->data_slices_per_group)
136 return -E_BAD_FEC_HEADER;
137 if (fg->h.group_bytes != h->group_bytes)
138 return -E_BAD_FEC_HEADER;
146 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
148 struct fecdec_group *fg;
150 FOR_EACH_FECDEC_GROUP(fg, pfd) {
151 if (fg->num_received_slices == 0)
157 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
159 struct fecdec_group *fg;
161 FOR_EACH_FECDEC_GROUP(fg, pfd) {
162 if (!group_complete(fg))
165 * Don't clear the first complete group if it has not yet been
168 if (fg == pfd->first_complete_group)
176 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
178 struct fecdec_group *fg, *oldest = NULL;
180 FOR_EACH_FECDEC_GROUP(fg, pfd) {
181 if (!oldest || oldest->h.group_num > fg->h.group_num)
184 if (!group_complete(oldest) && !group_empty(oldest))
185 PARA_WARNING_LOG("Clearing incomplete group %d "
186 "(contains %d slices)\n", oldest->h.group_num,
187 oldest->num_received_slices);
188 if (oldest == pfd->first_complete_group)
189 pfd->first_complete_group = NULL;
194 /* returns 1 if the group was found, 0 if not, negative on errors */
195 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
196 struct fecdec_group **result)
198 struct fecdec_group *fg;
199 int ret = find_group(h, pfd, &fg);
203 if (ret > 0) /* found group */
205 /* group not found */
206 fg = find_unused_group(pfd);
209 fg = try_to_free_group(pfd);
212 fg = free_oldest_group(pfd);
221 * returns 1 if slice was added, zero otherwise (because the group was already
222 * complete). In any case the number of received slices is being increased by
225 static int add_slice(char *buf, struct fecdec_group *fg)
229 if (group_complete(fg)) {
230 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
231 fg->h.group_num, fg->h.slice_num);
232 fg->num_received_slices++;
235 slice_num = fg->h.slice_num;
236 if (fg->num_slices == 0) {
237 fg->num_slices = fg->h.slices_per_group;
238 fg->idx = para_malloc(fg->num_slices * sizeof(int));
239 fg->data = para_malloc(fg->num_slices * sizeof(unsigned char *));
240 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
242 r = fg->num_received_slices;
243 fg->idx[r] = slice_num;
244 fg->data[r] = para_malloc(fg->h.slice_bytes);
245 memcpy(fg->data[r], buf, fg->h.slice_bytes);
246 fg->num_received_slices++;
251 * The different states of a complete FEC group.
253 * Even if a FEC group has been received successfully, it probably can not be
254 * used right away because some streams (ogg, wma) need to receive an audio
255 * file header before decoding can start.
257 enum fec_group_usability {
258 /** Drop the group (because we did not receive the header yet). */
260 /** Use all data in the group. */
262 /** Use the group, but drop its audio file header. */
263 FEC_GROUP_USABLE_SKIP_HEADER,
264 /** Use the group, including its header. */
265 FEC_GROUP_USABLE_WITH_HEADER
268 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
269 struct private_fecdec_data *pfd)
271 struct fec_header *h = &fg->h;
273 if (!h->header_stream)
274 return FEC_GROUP_USABLE;
275 if (pfd->have_header) {
276 if (h->audio_header_size)
277 return FEC_GROUP_USABLE_SKIP_HEADER;
278 return FEC_GROUP_USABLE;
281 return FEC_GROUP_USABLE;
282 if (fg->h.audio_header_size)
283 return FEC_GROUP_USABLE_WITH_HEADER;
284 return FEC_GROUP_UNUSABLE;
287 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
289 int i, ret, sb = fg->h.slice_bytes;
290 size_t written, need;
291 struct private_fecdec_data *pfd = fn->private_data;
292 enum fec_group_usability u = group_is_usable(fg, pfd);
294 if (u == FEC_GROUP_UNUSABLE) {
295 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
298 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
299 fg->h.data_slices_per_group);
300 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
303 pfd->have_header = 1;
305 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
306 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
308 PARA_DEBUG_LOG("skipping %d header slices\n", i);
310 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
311 fg->h.group_num, fg->h.group_bytes,
312 fg->h.data_slices_per_group * sb);
313 need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
314 if (need > fn->bufsize) {
315 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
316 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
317 return -E_FECDEC_OVERRUN;
318 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
319 fn->buf = para_realloc(fn->buf, fn->bufsize);
321 if (u == FEC_GROUP_USABLE_WITH_HEADER) {
322 PARA_INFO_LOG("writing audio file header\n");
324 for (i = 0; i < fg->h.data_slices_per_group; i++) {
326 if (written >= fg->h.audio_header_size)
328 if (sb + written > fg->h.audio_header_size)
329 n = fg->h.audio_header_size - written;
330 memcpy(fn->buf + fn->loaded, fg->data[i], n);
336 for (; i < fg->h.data_slices_per_group; i++) {
338 if (n + written > fg->h.group_bytes)
339 n = fg->h.group_bytes - written;
340 memcpy(fn->buf + fn->loaded, fg->data[i], n);
348 * Read a fec header from a buffer.
350 * \param buf The buffer to write to.
351 * \param h The fec header to write.
353 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
357 if (len < FEC_HEADER_SIZE)
359 magic = read_u32(buf);
360 if (magic != FEC_MAGIC)
361 return -E_BAD_FEC_HEADER;
362 h->slices_per_group = read_u8(buf + 4);
363 h->data_slices_per_group = read_u8(buf + 5);
364 h->audio_header_size = read_u32(buf + 6);
366 h->group_num = read_u32(buf + 10);
367 h->group_bytes = read_u32(buf + 14);
369 h->slice_num = read_u8(buf + 18);
370 h->slice_bytes = read_u16(buf + 20);
371 h->bos = read_u8(buf + 22);
372 h->header_stream = read_u8(buf + 23);
373 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
374 return -E_FECDEC_EOF;
375 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
376 // h->group_num, h->slice_num, h->slices_per_group);
380 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
381 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
382 struct filter_node *fn)
384 struct fecdec_group *fg;
386 struct private_fecdec_data *pfd = fn->private_data;
388 if (h->slice_bytes > len) /* can not use the thing, try to read more */
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 /* decode and clear the first group */
417 ret = decode_group(pfd->first_complete_group, fn);
420 clear_group(pfd->first_complete_group);
421 pfd->first_complete_group = NULL;
423 ret = decode_group(fg, fn);
429 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
434 ret = read_fec_header(buf, len, &h);
438 return -E_BAD_SLICE_SIZE;
439 if (h.slice_num > h.slices_per_group)
440 return -E_BAD_SLICE_NUM;
441 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
443 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
446 return FEC_HEADER_SIZE + h.slice_bytes;
449 static void fecdec_close(struct filter_node *fn)
451 struct private_fecdec_data *pfd = fn->private_data;
452 struct fecdec_group *fg;
454 FOR_EACH_FECDEC_GROUP(fg, pfd)
459 free(fn->private_data);
460 fn->private_data = NULL;
463 static void fecdec_open(struct filter_node *fn)
465 struct private_fecdec_data *pfd;
466 fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
467 fn->buf = para_malloc(fn->bufsize);
468 pfd = para_calloc(sizeof(*pfd));
469 fn->private_data = pfd;
474 * The init function of the fecdec filter.
476 * \param f struct to initialize.
478 void fecdec_filter_init(struct filter *f)
481 f->close = fecdec_close;
482 f->open = fecdec_open;