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 /** Size of the output buffer of the fecdec filter. */
31 #define FECDEC_OUTBUF_SIZE (1024 * 1024) /* FIXME: This has to depend on the fec params */
33 /** Data read from the header of a slice. */
35 /** Total number of slices in this group. */
36 uint8_t slices_per_group;
37 /** Number of slices needed to start decoding. */
38 uint8_t data_slices_per_group;
39 /** Size of the ogg vorbis header (zero for mp3, aac). */
40 uint32_t audio_header_size;
41 /** Number of the FEC group this slice belongs to. */
43 /** Size of the data in this FEC group. */
45 /** Number of this slice in the group. */
47 /** Used data bytes of this slice. */
49 /** Non-zero if this group is the beginning of the stream. */
51 /** Non-zero if this stream embedds audio headers into fec groups. */
52 uint8_t header_stream;
56 * The status of one partially received FEC group.
59 /** The header read from the last slice. */
61 /** How many slices received so far. */
62 int num_received_slices;
63 /** The size of the \a idx and the \a data arrays below. */
65 /** Array of indices of the received slices. */
67 /** Content of the received slices. */
72 * Data private to the fecdec filter.
74 struct private_fecdec_data {
75 /** Used by the fec core code. */
76 struct fec_parms *fec;
77 /** Keeps track of what was received so far. */
78 struct fecdec_group groups[NUM_FEC_GROUPS];
82 /** Iterate over all fecdec groups. */
83 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
84 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
86 static int group_complete(struct fecdec_group *fg)
88 return fg->num_received_slices >= fg->h.data_slices_per_group;
91 static int group_empty(struct fecdec_group *fg)
93 return fg->num_received_slices == 0;
96 static void clear_group(struct fecdec_group *fg)
100 for (i = 0; i < fg->num_slices; i++) {
108 memset(&fg->h, 0, sizeof(struct fec_header));
109 fg->num_received_slices = 0;
112 static int find_group(struct fec_header *h,
113 struct private_fecdec_data *pfd, struct fecdec_group **result)
115 struct fecdec_group *fg;
117 FOR_EACH_FECDEC_GROUP(fg, pfd) {
118 if (fg->h.group_num != h->group_num)
120 if (fg->num_received_slices == 0)
122 if (fg->h.slices_per_group != h->slices_per_group)
123 return -E_BAD_FEC_HEADER;
124 if (fg->h.data_slices_per_group != h->data_slices_per_group)
125 return -E_BAD_FEC_HEADER;
126 if (fg->h.group_bytes != h->group_bytes)
127 return -E_BAD_FEC_HEADER;
135 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
137 struct fecdec_group *fg;
139 FOR_EACH_FECDEC_GROUP(fg, pfd) {
140 if (fg->num_received_slices == 0)
146 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
148 struct fecdec_group *fg;
150 FOR_EACH_FECDEC_GROUP(fg, pfd) {
151 if (!group_complete(fg))
159 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
161 struct fecdec_group *fg, *oldest = NULL;
163 FOR_EACH_FECDEC_GROUP(fg, pfd) {
164 if (!oldest || oldest->h.group_num > fg->h.group_num)
167 if (!group_complete(oldest) && !group_empty(oldest))
168 PARA_WARNING_LOG("Clearing incomplete group %d "
169 "(contains %d slices)\n", oldest->h.group_num,
170 oldest->num_received_slices);
175 /* returns 1 if the group was found, 0 if not, negative on errors */
176 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
177 struct fecdec_group **result)
179 struct fecdec_group *fg;
180 int ret = find_group(h, pfd, &fg);
184 if (ret > 0) /* found group */
186 /* group not found */
187 fg = find_unused_group(pfd);
190 fg = try_to_free_group(pfd);
193 fg = free_oldest_group(pfd);
202 * returns 1 if slice was added, zero otherwise (because the group was already
203 * complete). In any case the number of received slices is being increased by
206 static int add_slice(char *buf, struct fecdec_group *fg)
210 if (group_complete(fg)) {
211 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
213 fg->num_received_slices++;
216 slice_num = fg->h.slice_num;
217 if (fg->num_slices == 0) {
218 fg->num_slices = fg->h.slices_per_group;
219 fg->idx = malloc(fg->num_slices * sizeof(int));
220 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
221 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
223 r = fg->num_received_slices;
224 fg->idx[r] = slice_num;
225 fg->data[r] = malloc(fg->h.slice_bytes);
226 memcpy(fg->data[r], buf, fg->h.slice_bytes);
227 fg->num_received_slices++;
231 enum fec_group_usability {
234 FEC_GROUP_USABLE_SKIP_HEADER,
237 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
238 struct private_fecdec_data *pfd)
240 struct fec_header *h = &fg->h;
242 if (!h->header_stream)
243 return FEC_GROUP_USABLE;
244 if (pfd->have_header) {
245 if (h->audio_header_size)
246 return FEC_GROUP_USABLE_SKIP_HEADER;
247 return FEC_GROUP_USABLE;
250 return FEC_GROUP_USABLE;
251 if (fg->h.audio_header_size)
252 return FEC_GROUP_USABLE;
253 return FEC_GROUP_UNUSABLE;
256 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
258 int i, ret, sb = fg->h.slice_bytes;
260 struct private_fecdec_data *pfd = fn->private_data;
261 enum fec_group_usability u = group_is_usable(fg, pfd);
263 if (u == FEC_GROUP_UNUSABLE) {
264 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
267 PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
268 fg->h.data_slices_per_group);
269 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
272 pfd->have_header = 1;
274 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
275 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
277 PARA_DEBUG_LOG("skipping %d header slices\n", i);
279 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
280 fg->h.group_num, fg->h.group_bytes,
281 fg->h.data_slices_per_group * sb);
282 for (; i < fg->h.data_slices_per_group; i++) {
284 if (n + written > fg->h.group_bytes)
285 n = fg->h.group_bytes - written;
286 if (fn->loaded + n > fn->bufsize)
287 return -E_FECDEC_OVERRUN;
288 memcpy(fn->buf + fn->loaded, fg->data[i], n);
296 * Read a fec header from a buffer.
298 * \param buf The buffer to write to.
299 * \param h The fec header to write.
301 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
305 if (len < FEC_HEADER_SIZE)
307 magic = read_u32(buf);
308 if (magic != FEC_MAGIC)
309 return -E_BAD_FEC_HEADER;
310 h->slices_per_group = read_u8(buf + 4);
311 h->data_slices_per_group = read_u8(buf + 5);
312 h->audio_header_size = read_u32(buf + 6);
314 h->group_num = read_u32(buf + 10);
315 h->group_bytes = read_u32(buf + 14);
317 h->slice_num = read_u8(buf + 18);
318 h->slice_bytes = read_u16(buf + 20);
319 h->bos = read_u8(buf + 22);
320 h->header_stream = read_u8(buf + 23);
321 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
322 return -E_FECDEC_EOF;
323 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
324 // h->group_num, h->slice_num, h->slices_per_group);
328 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
329 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
330 struct filter_node *fn)
332 struct fecdec_group *fg;
334 struct private_fecdec_data *pfd = fn->private_data;
336 if (h->slice_bytes > len) /* can not use the thing, try to read more */
338 ret = get_group(h, pfd, &fg);
341 if (!add_slice(buf, fg))
343 if (group_complete(fg)) {
345 int k = h->data_slices_per_group, n = h->slices_per_group;
346 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
347 ret = fec_new(k, n, &pfd->fec);
351 ret = decode_group(fg, fn);
358 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
363 ret = read_fec_header(buf, len, &h);
366 if (!h.slice_bytes || h.slice_bytes > fn->bufsize)
367 return -E_BAD_SLICE_SIZE;
368 if (h.slice_num > h.slices_per_group)
369 return -E_BAD_SLICE_NUM;
370 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
372 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
375 return FEC_HEADER_SIZE + h.slice_bytes;
378 static void fecdec_close(struct filter_node *fn)
380 struct private_fecdec_data *pfd = fn->private_data;
381 struct fecdec_group *fg;
383 FOR_EACH_FECDEC_GROUP(fg, pfd)
388 free(fn->private_data);
389 fn->private_data = NULL;
392 static void fecdec_open(struct filter_node *fn)
394 fn->bufsize = FECDEC_OUTBUF_SIZE;
395 fn->buf = para_malloc(fn->bufsize);
396 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
401 * The init function of the fecdec filter.
403 * \param f struct to initialize.
405 void fecdec_filter_init(struct filter *f)
408 f->close = fecdec_close;
409 f->open = fecdec_open;