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 fec-decodes an audio stream. */
17 #include "portable_io.h"
22 * How many FEC groups to store in memory.
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
28 #define NUM_FEC_GROUPS 3
30 /** Default size of the output buffer of the fecdec filter. */
31 #define FECDEC_DEFAULT_OUTBUF_SIZE (16 * 1024)
32 /** Maximal size of the output buffer of the fecdec filter. */
33 #define FECDEC_MAX_OUTBUF_SIZE (1024 * 1024)
35 /** Data read from the header of a slice. */
37 /** Total number of slices in this group. */
38 uint8_t slices_per_group;
39 /** Number of slices needed to start decoding. */
40 uint8_t data_slices_per_group;
41 /** Size of the ogg vorbis header (zero for mp3, aac). */
42 uint32_t audio_header_size;
43 /** Number of the FEC group this slice belongs to. */
45 /** Size of the data in this FEC group. */
47 /** Number of this slice in the group. */
49 /** Used data bytes of this slice. */
51 /** Non-zero if this group is the beginning of the stream. */
53 /** Non-zero if this stream embedds audio headers into fec groups. */
54 uint8_t header_stream;
58 * The status of one partially received FEC group.
61 /** The header read from the last slice. */
63 /** How many slices received so far. */
64 int num_received_slices;
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];
84 /** Iterate over all fecdec groups. */
85 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
86 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
88 static int group_complete(struct fecdec_group *fg)
90 return fg->num_received_slices >= fg->h.data_slices_per_group;
93 static int group_empty(struct fecdec_group *fg)
95 return fg->num_received_slices == 0;
98 static void clear_group(struct fecdec_group *fg)
102 for (i = 0; i < fg->num_slices; i++) {
110 memset(&fg->h, 0, sizeof(struct fec_header));
111 fg->num_received_slices = 0;
114 static int find_group(struct fec_header *h,
115 struct private_fecdec_data *pfd, struct fecdec_group **result)
117 struct fecdec_group *fg;
119 FOR_EACH_FECDEC_GROUP(fg, pfd) {
120 if (fg->h.group_num != h->group_num)
122 if (fg->h.slices_per_group != h->slices_per_group)
124 if (fg->h.data_slices_per_group != h->data_slices_per_group)
132 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
134 struct fecdec_group *fg;
136 FOR_EACH_FECDEC_GROUP(fg, pfd) {
137 if (fg->num_received_slices == 0)
143 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
145 struct fecdec_group *fg;
147 FOR_EACH_FECDEC_GROUP(fg, pfd) {
148 if (!group_complete(fg))
156 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
158 struct fecdec_group *fg, *oldest = NULL;
160 FOR_EACH_FECDEC_GROUP(fg, pfd) {
161 if (!oldest || oldest->h.group_num > fg->h.group_num)
164 if (!group_complete(oldest) && !group_empty(oldest))
165 PARA_WARNING_LOG("Clearing incomplete group %d "
166 "(contains %d slices)\n", fg->h.group_num,
167 fg->num_received_slices);
172 /* returns 1 if the group was found, 0 if not, negative on errors */
173 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
174 struct fecdec_group **result)
176 struct fecdec_group *fg;
177 int ret = find_group(h, pfd, &fg);
181 if (ret > 0) /* found group */
183 /* group not found */
184 fg = find_unused_group(pfd);
187 fg = try_to_free_group(pfd);
190 fg = free_oldest_group(pfd);
199 * returns 1 if slice was added, zero otherwise (because the group was already
200 * complete). In any case the number of received slices is being increased by
203 static int add_slice(char *buf, struct fecdec_group *fg)
207 if (group_complete(fg)) {
208 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
210 fg->num_received_slices++;
213 slice_num = fg->h.slice_num;
214 if (fg->num_slices == 0) {
215 fg->num_slices = fg->h.slices_per_group;
216 fg->idx = malloc(fg->num_slices * sizeof(int));
217 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
218 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
220 r = fg->num_received_slices;
221 fg->idx[r] = slice_num;
222 fg->data[r] = malloc(fg->h.slice_bytes);
223 memcpy(fg->data[r], buf, fg->h.slice_bytes);
224 fg->num_received_slices++;
228 enum fec_group_usability {
231 FEC_GROUP_USABLE_SKIP_HEADER,
234 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
235 struct private_fecdec_data *pfd)
237 struct fec_header *h = &fg->h;
239 if (!h->header_stream)
240 return FEC_GROUP_USABLE;
241 if (pfd->have_header) {
242 if (h->audio_header_size)
243 return FEC_GROUP_USABLE_SKIP_HEADER;
244 return FEC_GROUP_USABLE;
247 return FEC_GROUP_USABLE;
248 if (fg->h.audio_header_size)
249 return FEC_GROUP_USABLE;
250 return FEC_GROUP_UNUSABLE;
253 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
255 int i, ret, sb = fg->h.slice_bytes;
256 size_t written = 0, need;
257 struct private_fecdec_data *pfd = fn->private_data;
258 enum fec_group_usability u = group_is_usable(fg, pfd);
260 if (u == FEC_GROUP_UNUSABLE) {
261 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
264 PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
265 fg->h.data_slices_per_group);
266 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
269 pfd->have_header = 1;
271 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
272 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
274 PARA_DEBUG_LOG("skipping %d header slices\n", i);
276 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
277 fg->h.group_num, fg->h.group_bytes,
278 fg->h.data_slices_per_group * sb);
279 need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
280 if (need > fn->bufsize) {
281 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
282 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
283 return -E_FECDEC_OVERRUN;
284 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
285 fn->buf = para_realloc(fn->buf, fn->bufsize);
287 for (; i < fg->h.data_slices_per_group; i++) {
289 if (n + written > fg->h.group_bytes)
290 n = fg->h.group_bytes - written;
291 memcpy(fn->buf + fn->loaded, fg->data[i], n);
299 * Read a fec header from a buffer.
301 * \param buf The buffer to write to.
302 * \param h The fec header to write.
304 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
308 if (len < FEC_HEADER_SIZE)
310 magic = read_u32(buf);
311 if (magic != FEC_MAGIC)
312 return -E_BAD_FEC_HEADER;
313 h->slices_per_group = read_u8(buf + 4);
314 h->data_slices_per_group = read_u8(buf + 5);
315 h->audio_header_size = read_u32(buf + 6);
317 h->group_num = read_u32(buf + 10);
318 h->group_bytes = read_u32(buf + 14);
320 h->slice_num = read_u8(buf + 18);
321 h->slice_bytes = read_u16(buf + 20);
322 h->bos = read_u8(buf + 22);
323 h->header_stream = read_u8(buf + 23);
324 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
325 return -E_FECDEC_EOF;
326 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
327 // h->group_num, h->slice_num, h->slices_per_group);
331 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
332 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
333 struct filter_node *fn)
335 struct fecdec_group *fg;
337 struct private_fecdec_data *pfd = fn->private_data;
339 if (h->slice_bytes > len) /* can not use the thing, try to read more */
341 ret = get_group(h, pfd, &fg);
344 if (!add_slice(buf, fg))
346 if (group_complete(fg)) {
348 int k = h->data_slices_per_group, n = h->slices_per_group;
349 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
350 ret = fec_new(k, n, &pfd->fec);
354 ret = decode_group(fg, fn);
361 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
366 ret = read_fec_header(buf, len, &h);
369 if (!h.slice_bytes || h.slice_bytes > fn->bufsize)
370 return -E_BAD_SLICE_SIZE;
371 if (h.slice_num > h.slices_per_group)
372 return -E_BAD_SLICE_NUM;
373 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
375 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
378 return FEC_HEADER_SIZE + h.slice_bytes;
381 static void fecdec_close(struct filter_node *fn)
383 struct private_fecdec_data *pfd = fn->private_data;
384 struct fecdec_group *fg;
386 FOR_EACH_FECDEC_GROUP(fg, pfd)
391 free(fn->private_data);
392 fn->private_data = NULL;
395 static void fecdec_open(struct filter_node *fn)
397 fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
398 fn->buf = para_malloc(fn->bufsize);
399 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
404 * The init function of the fecdec filter.
406 * \param f struct to initialize.
408 void fecdec_filter_init(struct filter *f)
411 f->close = fecdec_close;
412 f->open = fecdec_open;