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 (128 * 1024)
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. */
52 * The status of one partially received FEC group.
55 /** The header read from the last slice. */
57 /** How many slices received so far. */
58 int num_received_slices;
59 /** The size of the \a idx and the \a data arrays below. */
61 /** Array of indices of the received slices. */
63 /** Content of the received slices. */
68 * Data private to the fecdec filter.
70 struct private_fecdec_data {
71 /** Used by the fec core code. */
72 struct fec_parms *fec;
73 /** Keeps track of what was received so far. */
74 struct fecdec_group groups[NUM_FEC_GROUPS];
77 /** Iterate over all fecdec groups. */
78 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
79 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
81 static int group_complete(struct fecdec_group *fg)
83 return fg->num_received_slices >= fg->h.data_slices_per_group;
86 static int group_empty(struct fecdec_group *fg)
88 return fg->num_received_slices == 0;
91 static void clear_group(struct fecdec_group *fg)
95 for (i = 0; i < fg->num_slices; i++) {
103 memset(&fg->h, 0, sizeof(struct fec_header));
104 fg->num_received_slices = 0;
107 static int find_group(struct fec_header *h,
108 struct private_fecdec_data *pfd, struct fecdec_group **result)
110 struct fecdec_group *fg;
112 FOR_EACH_FECDEC_GROUP(fg, pfd) {
113 if (fg->h.group_num != h->group_num)
115 if (fg->h.slices_per_group != h->slices_per_group)
117 if (fg->h.data_slices_per_group != h->data_slices_per_group)
125 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
127 struct fecdec_group *fg;
129 FOR_EACH_FECDEC_GROUP(fg, pfd) {
130 if (fg->num_received_slices == 0)
136 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
138 struct fecdec_group *fg;
140 FOR_EACH_FECDEC_GROUP(fg, pfd) {
141 if (!group_complete(fg))
149 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
151 struct fecdec_group *fg, *oldest = NULL;
153 FOR_EACH_FECDEC_GROUP(fg, pfd) {
154 if (!oldest || oldest->h.group_num > fg->h.group_num)
157 if (!group_complete(oldest) && !group_empty(oldest))
158 PARA_WARNING_LOG("Clearing incomplete group %d "
159 "(contains %d slices)\n", fg->h.group_num,
160 fg->num_received_slices);
165 /* returns 1 if the group was found, 0 if not, negative on errors */
166 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
167 struct fecdec_group **result)
169 struct fecdec_group *fg;
170 int ret = find_group(h, pfd, &fg);
174 if (ret > 0) /* found group */
176 /* group not found */
177 fg = find_unused_group(pfd);
180 fg = try_to_free_group(pfd);
183 fg = free_oldest_group(pfd);
192 * returns 1 if slice was added, zero otherwise (because the group was already
193 * complete). In any case the number of received slices is being increased by
196 static int add_slice(char *buf, struct fecdec_group *fg)
200 if (group_complete(fg)) {
201 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
203 fg->num_received_slices++;
206 slice_num = fg->h.slice_num;
207 if (fg->num_slices == 0) {
208 fg->num_slices = fg->h.slices_per_group;
209 fg->idx = malloc(fg->num_slices * sizeof(int));
210 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
211 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
213 r = fg->num_received_slices;
214 fg->idx[r] = slice_num;
215 fg->data[r] = malloc(fg->h.slice_bytes);
216 memcpy(fg->data[r], buf, fg->h.slice_bytes);
217 fg->num_received_slices++;
221 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
223 int i, ret, sb = fg->h.slice_bytes;
225 struct private_fecdec_data *pfd = fn->private_data;
227 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
230 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
231 fg->h.group_num, fg->h.group_bytes,
232 fg->h.data_slices_per_group * sb);
233 for (i = 0; i < fg->h.data_slices_per_group; i++) {
235 if (n + written > fg->h.group_bytes)
236 n = fg->h.group_bytes - written;
237 if (fn->loaded + n > fn->bufsize)
238 return -E_FECDEC_OVERRUN;
239 memcpy(fn->buf + fn->loaded, fg->data[i], n);
247 * Read a fec header from a buffer.
249 * \param buf The buffer to write to.
250 * \param h The fec header to write.
252 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
256 if (len < FEC_HEADER_SIZE)
258 magic = read_u32(buf);
259 if (magic != FEC_MAGIC)
260 return -E_BAD_FEC_HEADER;
261 h->slices_per_group = read_u8(buf + 4);
262 h->data_slices_per_group = read_u8(buf + 5);
263 h->audio_header_size = read_u32(buf + 6);
265 h->group_num = read_u32(buf + 10);
266 h->group_bytes = read_u32(buf + 14);
268 h->slice_num = read_u8(buf + 18);
269 h->slice_bytes = read_u16(buf + 20);
270 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
271 return -E_FECDEC_EOF;
272 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
273 // h->group_num, h->slice_num, h->slices_per_group);
277 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
278 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
279 struct filter_node *fn)
281 struct fecdec_group *fg;
283 struct private_fecdec_data *pfd = fn->private_data;
285 if (h->slice_bytes > len) /* can not use the thing, try to read more */
287 ret = get_group(h, pfd, &fg);
290 if (!add_slice(buf, fg))
292 if (group_complete(fg)) {
294 int k = h->data_slices_per_group, n = h->slices_per_group;
295 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
296 ret = fec_new(k, n, &pfd->fec);
300 ret = decode_group(fg, fn);
307 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
312 ret = read_fec_header(buf, len, &h);
315 if (h.slice_bytes > fn->bufsize)
316 return -E_BAD_SLICE_SIZE;
317 if (h.slice_num > h.slices_per_group)
318 return -E_BAD_SLICE_NUM;
319 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
321 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
324 return FEC_HEADER_SIZE + h.slice_bytes;
327 static void fecdec_close(struct filter_node *fn)
329 struct private_fecdec_data *pfd = fn->private_data;
330 struct fecdec_group *fg;
332 FOR_EACH_FECDEC_GROUP(fg, pfd)
336 free(fn->private_data);
337 fn->private_data = NULL;
340 static void fecdec_open(struct filter_node *fn)
342 fn->bufsize = FECDEC_OUTBUF_SIZE;
343 fn->buf = para_malloc(fn->bufsize);
344 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
349 * The init function of the fecdec filter.
351 * \param f struct to initialize.
353 void fecdec_filter_init(struct filter *f)
356 f->close = fecdec_close;
357 f->open = fecdec_open;