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. */
19 #include "portable_io.h"
24 * How many FEC groups to store in memory.
26 * Packet reordering requires to keep more than one FEC group in memory because
27 * slices belonging to the next FEC group may arrive before the current FEC group
30 #define NUM_FEC_GROUPS 3
32 /** Default size of the output buffer of the fecdec filter. */
33 #define FECDEC_DEFAULT_OUTBUF_SIZE (3 * 1024)
34 /** Maximal size of the output buffer of the fecdec filter. */
35 #define FECDEC_MAX_OUTBUF_SIZE (1024 * 1024)
37 /** Data read from the header of a slice. */
39 /** Total number of slices in this group. */
40 uint8_t slices_per_group;
41 /** Number of slices needed to start decoding. */
42 uint8_t data_slices_per_group;
43 /** Size of the ogg vorbis header (zero for mp3, aac). */
44 uint32_t audio_header_size;
45 /** Number of the FEC group this slice belongs to. */
47 /** Size of the data in this FEC group. */
49 /** Number of this slice in the group. */
51 /** Used data bytes of this slice. */
53 /** Non-zero if this group is the beginning of the stream. */
55 /** Non-zero if this stream embedds audio headers into fec groups. */
56 uint8_t header_stream;
60 * The status of one partially received FEC group.
63 /** The header read from the last slice. */
65 /** How many slices received so far. */
66 int num_received_slices;
67 /** The size of the \a idx and the \a data arrays below. */
69 /** Array of indices of the received slices. */
71 /** Content of the received slices. */
76 * Data private to the fecdec filter.
78 struct private_fecdec_data {
79 /** Used by the fec core code. */
80 struct fec_parms *fec;
81 /** Keeps track of what was received so far. */
82 struct fecdec_group groups[NUM_FEC_GROUPS];
83 /** Whether an audio file header was already received. */
85 /** Points to the first received group. */
86 struct fecdec_group *first_complete_group;
89 /** Iterate over all fecdec groups. */
90 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
91 (g) < (d)->groups + NUM_FEC_GROUPS; (g)++)
93 static int group_complete(struct fecdec_group *fg)
95 return fg->num_received_slices >= fg->h.data_slices_per_group;
98 static int group_empty(struct fecdec_group *fg)
100 return fg->num_received_slices == 0;
103 static void clear_group(struct fecdec_group *fg)
107 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++;
246 enum fec_group_usability {
249 FEC_GROUP_USABLE_SKIP_HEADER,
250 FEC_GROUP_USABLE_WITH_HEADER
253 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
254 struct private_fecdec_data *pfd)
256 struct fec_header *h = &fg->h;
258 if (!h->header_stream)
259 return FEC_GROUP_USABLE;
260 if (pfd->have_header) {
261 if (h->audio_header_size)
262 return FEC_GROUP_USABLE_SKIP_HEADER;
263 return FEC_GROUP_USABLE;
266 return FEC_GROUP_USABLE;
267 if (fg->h.audio_header_size)
268 return FEC_GROUP_USABLE_WITH_HEADER;
269 return FEC_GROUP_UNUSABLE;
272 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
274 int i, ret, sb = fg->h.slice_bytes;
275 size_t written, need;
276 struct private_fecdec_data *pfd = fn->private_data;
277 enum fec_group_usability u = group_is_usable(fg, pfd);
279 if (u == FEC_GROUP_UNUSABLE) {
280 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
283 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
284 fg->h.data_slices_per_group);
285 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
288 pfd->have_header = 1;
290 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
291 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
293 PARA_DEBUG_LOG("skipping %d header slices\n", i);
295 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
296 fg->h.group_num, fg->h.group_bytes,
297 fg->h.data_slices_per_group * sb);
298 need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
299 if (need > fn->bufsize) {
300 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
301 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
302 return -E_FECDEC_OVERRUN;
303 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
304 fn->buf = para_realloc(fn->buf, fn->bufsize);
306 if (u == FEC_GROUP_USABLE_WITH_HEADER) {
307 PARA_INFO_LOG("writing audio file header\n");
309 for (i = 0; i < fg->h.data_slices_per_group; i++) {
311 if (written >= fg->h.audio_header_size)
313 if (sb + written > fg->h.audio_header_size)
314 n = fg->h.audio_header_size - written;
315 memcpy(fn->buf + fn->loaded, fg->data[i], n);
321 for (; i < fg->h.data_slices_per_group; i++) {
323 if (n + written > fg->h.group_bytes)
324 n = fg->h.group_bytes - written;
325 memcpy(fn->buf + fn->loaded, fg->data[i], n);
333 * Read a fec header from a buffer.
335 * \param buf The buffer to write to.
336 * \param h The fec header to write.
338 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
342 if (len < FEC_HEADER_SIZE)
344 magic = read_u32(buf);
345 if (magic != FEC_MAGIC)
346 return -E_BAD_FEC_HEADER;
347 h->slices_per_group = read_u8(buf + 4);
348 h->data_slices_per_group = read_u8(buf + 5);
349 h->audio_header_size = read_u32(buf + 6);
351 h->group_num = read_u32(buf + 10);
352 h->group_bytes = read_u32(buf + 14);
354 h->slice_num = read_u8(buf + 18);
355 h->slice_bytes = read_u16(buf + 20);
356 h->bos = read_u8(buf + 22);
357 h->header_stream = read_u8(buf + 23);
358 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
359 return -E_FECDEC_EOF;
360 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
361 // h->group_num, h->slice_num, h->slices_per_group);
365 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
366 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
367 struct filter_node *fn)
369 struct fecdec_group *fg;
371 struct private_fecdec_data *pfd = fn->private_data;
373 if (h->slice_bytes > len) /* can not use the thing, try to read more */
375 ret = get_group(h, pfd, &fg);
378 if (!add_slice(buf, fg)) /* group already complete */
380 if (!group_complete(fg))
382 /* this slice completed the group */
385 /* it's either the first or the second complete group */
386 if (!pfd->first_complete_group) { /* it's the first group */
387 enum fec_group_usability u = group_is_usable(fg, pfd);
388 assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
389 if (u == FEC_GROUP_UNUSABLE) /* forget it */
391 pfd->first_complete_group = fg; /* remember it */
394 /* we have two complete groups, let's go */
395 k = h->data_slices_per_group;
396 n = h->slices_per_group;
397 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
398 ret = fec_new(k, n, &pfd->fec);
401 /* decode and clear the first group */
402 ret = decode_group(pfd->first_complete_group, fn);
405 clear_group(pfd->first_complete_group);
406 pfd->first_complete_group = NULL;
408 ret = decode_group(fg, fn);
414 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
419 ret = read_fec_header(buf, len, &h);
423 return -E_BAD_SLICE_SIZE;
424 if (h.slice_num > h.slices_per_group)
425 return -E_BAD_SLICE_NUM;
426 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
428 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
431 return FEC_HEADER_SIZE + h.slice_bytes;
434 static void fecdec_close(struct filter_node *fn)
436 struct private_fecdec_data *pfd = fn->private_data;
437 struct fecdec_group *fg;
439 FOR_EACH_FECDEC_GROUP(fg, pfd)
444 free(fn->private_data);
445 fn->private_data = NULL;
448 static void fecdec_open(struct filter_node *fn)
450 struct private_fecdec_data *pfd;
451 fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
452 fn->buf = para_malloc(fn->bufsize);
453 pfd = para_calloc(sizeof(*pfd));
454 fn->private_data = pfd;
459 * The init function of the fecdec filter.
461 * \param f struct to initialize.
463 void fecdec_filter_init(struct filter *f)
466 f->close = fecdec_close;
467 f->open = fecdec_open;