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. */
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 (3 * 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 * The fecdec filter defers decoding of the first group until the first slice
75 * of the next group was received. This avoids buffer underruns in subsequent
76 * filters of the filter chain.
78 enum group_completion_status {
79 /** No complete group received so far. */
80 GCS_NO_COMPLETE_GROUP,
81 /** First group received, but not yet decoded. */
82 GCS_FIRST_GROUP_COMPLETE,
83 /** At least one complete group decoded. */
84 GCS_FIRST_GROUP_DECODED,
88 * Data private to the fecdec filter.
90 struct private_fecdec_data {
91 /** Used by the fec core code. */
92 struct fec_parms *fec;
93 /** Keeps track of what was received so far. */
94 struct fecdec_group groups[NUM_FEC_GROUPS];
95 /** Whether an audio file header was already received. */
97 /** See \ref group_completion_status. */
98 unsigned completion_status;
99 /** Points to the first received group. */
100 struct fecdec_group *first_complete_group;
103 /** Iterate over all fecdec groups. */
104 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
105 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
107 static int group_complete(struct fecdec_group *fg)
109 return fg->num_received_slices >= fg->h.data_slices_per_group;
112 static int group_empty(struct fecdec_group *fg)
114 return fg->num_received_slices == 0;
117 static void clear_group(struct fecdec_group *fg)
121 for (i = 0; i < fg->num_slices; i++) {
129 memset(&fg->h, 0, sizeof(struct fec_header));
130 fg->num_received_slices = 0;
133 static int find_group(struct fec_header *h,
134 struct private_fecdec_data *pfd, struct fecdec_group **result)
136 struct fecdec_group *fg;
138 FOR_EACH_FECDEC_GROUP(fg, pfd) {
139 if (fg->h.group_num != h->group_num)
141 if (fg->num_received_slices == 0)
143 if (fg->h.slices_per_group != h->slices_per_group)
144 return -E_BAD_FEC_HEADER;
145 if (fg->h.data_slices_per_group != h->data_slices_per_group)
146 return -E_BAD_FEC_HEADER;
147 if (fg->h.group_bytes != h->group_bytes)
148 return -E_BAD_FEC_HEADER;
156 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
158 struct fecdec_group *fg;
160 FOR_EACH_FECDEC_GROUP(fg, pfd) {
161 if (fg->num_received_slices == 0)
167 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
169 struct fecdec_group *fg;
171 FOR_EACH_FECDEC_GROUP(fg, pfd) {
172 if (!group_complete(fg))
175 * Don't clear the first complete group if it has not yet been
178 if (pfd->completion_status == GCS_FIRST_GROUP_COMPLETE
179 && pfd->first_complete_group == fg)
187 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
189 struct fecdec_group *fg, *oldest = NULL;
191 FOR_EACH_FECDEC_GROUP(fg, pfd) {
192 if (!oldest || oldest->h.group_num > fg->h.group_num)
195 if (!group_complete(oldest) && !group_empty(oldest))
196 PARA_WARNING_LOG("Clearing incomplete group %d "
197 "(contains %d slices)\n", oldest->h.group_num,
198 oldest->num_received_slices);
199 assert(pfd->completion_status != GCS_FIRST_GROUP_COMPLETE
200 || oldest != pfd->first_complete_group);
205 /* returns 1 if the group was found, 0 if not, negative on errors */
206 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
207 struct fecdec_group **result)
209 struct fecdec_group *fg;
210 int ret = find_group(h, pfd, &fg);
214 if (ret > 0) /* found group */
216 /* group not found */
217 fg = find_unused_group(pfd);
220 fg = try_to_free_group(pfd);
223 fg = free_oldest_group(pfd);
232 * returns 1 if slice was added, zero otherwise (because the group was already
233 * complete). In any case the number of received slices is being increased by
236 static int add_slice(char *buf, struct fecdec_group *fg)
240 if (group_complete(fg)) {
241 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
242 fg->h.group_num, fg->h.slice_num);
243 fg->num_received_slices++;
246 slice_num = fg->h.slice_num;
247 if (fg->num_slices == 0) {
248 fg->num_slices = fg->h.slices_per_group;
249 fg->idx = malloc(fg->num_slices * sizeof(int));
250 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
251 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
253 r = fg->num_received_slices;
254 fg->idx[r] = slice_num;
255 fg->data[r] = malloc(fg->h.slice_bytes);
256 memcpy(fg->data[r], buf, fg->h.slice_bytes);
257 fg->num_received_slices++;
261 enum fec_group_usability {
264 FEC_GROUP_USABLE_SKIP_HEADER,
267 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
268 struct private_fecdec_data *pfd)
270 struct fec_header *h = &fg->h;
272 if (!h->header_stream)
273 return FEC_GROUP_USABLE;
274 if (pfd->have_header) {
275 if (h->audio_header_size)
276 return FEC_GROUP_USABLE_SKIP_HEADER;
277 return FEC_GROUP_USABLE;
280 return FEC_GROUP_USABLE;
281 if (fg->h.audio_header_size)
282 return FEC_GROUP_USABLE;
283 return FEC_GROUP_UNUSABLE;
286 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
288 int i, ret, sb = fg->h.slice_bytes;
289 size_t written = 0, need;
290 struct private_fecdec_data *pfd = fn->private_data;
291 enum fec_group_usability u = group_is_usable(fg, pfd);
293 if (u == FEC_GROUP_UNUSABLE) {
294 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
297 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
298 fg->h.data_slices_per_group);
299 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
302 pfd->have_header = 1;
304 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
305 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
307 PARA_DEBUG_LOG("skipping %d header slices\n", i);
309 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
310 fg->h.group_num, fg->h.group_bytes,
311 fg->h.data_slices_per_group * sb);
312 need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
313 if (need > fn->bufsize) {
314 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
315 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
316 return -E_FECDEC_OVERRUN;
317 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
318 fn->buf = para_realloc(fn->buf, fn->bufsize);
320 for (; i < fg->h.data_slices_per_group; i++) {
322 if (n + written > fg->h.group_bytes)
323 n = fg->h.group_bytes - written;
324 memcpy(fn->buf + fn->loaded, fg->data[i], n);
332 * Read a fec header from a buffer.
334 * \param buf The buffer to write to.
335 * \param h The fec header to write.
337 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
341 if (len < FEC_HEADER_SIZE)
343 magic = read_u32(buf);
344 if (magic != FEC_MAGIC)
345 return -E_BAD_FEC_HEADER;
346 h->slices_per_group = read_u8(buf + 4);
347 h->data_slices_per_group = read_u8(buf + 5);
348 h->audio_header_size = read_u32(buf + 6);
350 h->group_num = read_u32(buf + 10);
351 h->group_bytes = read_u32(buf + 14);
353 h->slice_num = read_u8(buf + 18);
354 h->slice_bytes = read_u16(buf + 20);
355 h->bos = read_u8(buf + 22);
356 h->header_stream = read_u8(buf + 23);
357 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
358 return -E_FECDEC_EOF;
359 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
360 // h->group_num, h->slice_num, h->slices_per_group);
364 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
365 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
366 struct filter_node *fn)
368 struct fecdec_group *fg;
370 struct private_fecdec_data *pfd = fn->private_data;
372 if (h->slice_bytes > len) /* can not use the thing, try to read more */
374 ret = get_group(h, pfd, &fg);
377 if (!add_slice(buf, fg))
379 if (group_complete(fg)) {
380 if (pfd->completion_status == GCS_NO_COMPLETE_GROUP) {
381 pfd->completion_status = GCS_FIRST_GROUP_COMPLETE;
382 pfd->first_complete_group = fg;
386 ret = decode_group(fg, fn);
391 if (pfd->completion_status == GCS_NO_COMPLETE_GROUP)
393 if (pfd->completion_status == GCS_FIRST_GROUP_DECODED)
395 if (fg == pfd->first_complete_group)
398 k = h->data_slices_per_group;
399 n = h->slices_per_group;
400 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
401 ret = fec_new(k, n, &pfd->fec);
404 ret = decode_group(pfd->first_complete_group, fn);
407 pfd->completion_status = GCS_FIRST_GROUP_DECODED;
411 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
416 ret = read_fec_header(buf, len, &h);
420 return -E_BAD_SLICE_SIZE;
421 if (h.slice_num > h.slices_per_group)
422 return -E_BAD_SLICE_NUM;
423 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
425 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
428 return FEC_HEADER_SIZE + h.slice_bytes;
431 static void fecdec_close(struct filter_node *fn)
433 struct private_fecdec_data *pfd = fn->private_data;
434 struct fecdec_group *fg;
436 FOR_EACH_FECDEC_GROUP(fg, pfd)
441 free(fn->private_data);
442 fn->private_data = NULL;
445 static void fecdec_open(struct filter_node *fn)
447 struct private_fecdec_data *pfd;
448 fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
449 fn->buf = para_malloc(fn->bufsize);
450 pfd = para_calloc(sizeof(*pfd));
451 pfd->completion_status = GCS_NO_COMPLETE_GROUP;
452 fn->private_data = pfd;
457 * The init function of the fecdec filter.
459 * \param f struct to initialize.
461 void fecdec_filter_init(struct filter *f)
464 f->close = fecdec_close;
465 f->open = fecdec_open;