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. */
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. */
87 /** Iterate over all fecdec groups. */
88 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
89 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
91 static int group_complete(struct fecdec_group
*fg
)
93 return fg
->num_received_slices
>= fg
->h
.data_slices_per_group
;
96 static int group_empty(struct fecdec_group
*fg
)
98 return fg
->num_received_slices
== 0;
101 static void clear_group(struct fecdec_group
*fg
)
105 for (i
= 0; i
< fg
->num_slices
; i
++) {
113 memset(&fg
->h
, 0, sizeof(struct fec_header
));
114 fg
->num_received_slices
= 0;
117 static int find_group(struct fec_header
*h
,
118 struct private_fecdec_data
*pfd
, struct fecdec_group
**result
)
120 struct fecdec_group
*fg
;
122 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
123 if (fg
->h
.group_num
!= h
->group_num
)
125 if (fg
->num_received_slices
== 0)
127 if (fg
->h
.slices_per_group
!= h
->slices_per_group
)
128 return -E_BAD_FEC_HEADER
;
129 if (fg
->h
.data_slices_per_group
!= h
->data_slices_per_group
)
130 return -E_BAD_FEC_HEADER
;
131 if (fg
->h
.group_bytes
!= h
->group_bytes
)
132 return -E_BAD_FEC_HEADER
;
140 static struct fecdec_group
*find_unused_group(struct private_fecdec_data
*pfd
)
142 struct fecdec_group
*fg
;
144 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
145 if (fg
->num_received_slices
== 0)
151 static struct fecdec_group
*try_to_free_group(struct private_fecdec_data
*pfd
)
153 struct fecdec_group
*fg
;
155 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
156 if (!group_complete(fg
))
164 static struct fecdec_group
*free_oldest_group(struct private_fecdec_data
*pfd
)
166 struct fecdec_group
*fg
, *oldest
= NULL
;
168 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
169 if (!oldest
|| oldest
->h
.group_num
> fg
->h
.group_num
)
172 if (!group_complete(oldest
) && !group_empty(oldest
))
173 PARA_WARNING_LOG("Clearing incomplete group %d "
174 "(contains %d slices)\n", oldest
->h
.group_num
,
175 oldest
->num_received_slices
);
180 /* returns 1 if the group was found, 0 if not, negative on errors */
181 static int get_group(struct fec_header
*h
, struct private_fecdec_data
*pfd
,
182 struct fecdec_group
**result
)
184 struct fecdec_group
*fg
;
185 int ret
= find_group(h
, pfd
, &fg
);
189 if (ret
> 0) /* found group */
191 /* group not found */
192 fg
= find_unused_group(pfd
);
195 fg
= try_to_free_group(pfd
);
198 fg
= free_oldest_group(pfd
);
207 * returns 1 if slice was added, zero otherwise (because the group was already
208 * complete). In any case the number of received slices is being increased by
211 static int add_slice(char *buf
, struct fecdec_group
*fg
)
215 if (group_complete(fg
)) {
216 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
218 fg
->num_received_slices
++;
221 slice_num
= fg
->h
.slice_num
;
222 if (fg
->num_slices
== 0) {
223 fg
->num_slices
= fg
->h
.slices_per_group
;
224 fg
->idx
= malloc(fg
->num_slices
* sizeof(int));
225 fg
->data
= malloc(fg
->num_slices
* sizeof(unsigned char *));
226 memset(fg
->data
, 0, fg
->num_slices
* sizeof(unsigned char *));
228 r
= fg
->num_received_slices
;
229 fg
->idx
[r
] = slice_num
;
230 fg
->data
[r
] = malloc(fg
->h
.slice_bytes
);
231 memcpy(fg
->data
[r
], buf
, fg
->h
.slice_bytes
);
232 fg
->num_received_slices
++;
236 enum fec_group_usability
{
239 FEC_GROUP_USABLE_SKIP_HEADER
,
242 static enum fec_group_usability
group_is_usable(struct fecdec_group
*fg
,
243 struct private_fecdec_data
*pfd
)
245 struct fec_header
*h
= &fg
->h
;
247 if (!h
->header_stream
)
248 return FEC_GROUP_USABLE
;
249 if (pfd
->have_header
) {
250 if (h
->audio_header_size
)
251 return FEC_GROUP_USABLE_SKIP_HEADER
;
252 return FEC_GROUP_USABLE
;
255 return FEC_GROUP_USABLE
;
256 if (fg
->h
.audio_header_size
)
257 return FEC_GROUP_USABLE
;
258 return FEC_GROUP_UNUSABLE
;
261 static int decode_group(struct fecdec_group
*fg
, struct filter_node
*fn
)
263 int i
, ret
, sb
= fg
->h
.slice_bytes
;
264 size_t written
= 0, need
;
265 struct private_fecdec_data
*pfd
= fn
->private_data
;
266 enum fec_group_usability u
= group_is_usable(fg
, pfd
);
268 if (u
== FEC_GROUP_UNUSABLE
) {
269 PARA_INFO_LOG("dropping unusable group %d\n", fg
->h
.group_num
);
272 PARA_DEBUG_LOG("decoding group %d %d slices\n", fg
->h
.group_num
,
273 fg
->h
.data_slices_per_group
);
274 ret
= fec_decode(pfd
->fec
, fg
->data
, fg
->idx
, sb
);
277 pfd
->have_header
= 1;
279 if (u
== FEC_GROUP_USABLE_SKIP_HEADER
) {
280 i
= ROUND_UP(fg
->h
.audio_header_size
, fg
->h
.slice_bytes
)
282 PARA_DEBUG_LOG("skipping %d header slices\n", i
);
284 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
285 fg
->h
.group_num
, fg
->h
.group_bytes
,
286 fg
->h
.data_slices_per_group
* sb
);
287 need
= fn
->loaded
+ (fg
->h
.data_slices_per_group
- i
)* sb
;
288 if (need
> fn
->bufsize
) {
289 fn
->bufsize
= PARA_MAX(fn
->bufsize
* 2, need
);
290 if (fn
->bufsize
> FECDEC_MAX_OUTBUF_SIZE
)
291 return -E_FECDEC_OVERRUN
;
292 PARA_INFO_LOG("increasing fec buf to %zu\n", fn
->bufsize
);
293 fn
->buf
= para_realloc(fn
->buf
, fn
->bufsize
);
295 for (; i
< fg
->h
.data_slices_per_group
; i
++) {
297 if (n
+ written
> fg
->h
.group_bytes
)
298 n
= fg
->h
.group_bytes
- written
;
299 memcpy(fn
->buf
+ fn
->loaded
, fg
->data
[i
], n
);
307 * Read a fec header from a buffer.
309 * \param buf The buffer to write to.
310 * \param h The fec header to write.
312 static int read_fec_header(char *buf
, size_t len
, struct fec_header
*h
)
316 if (len
< FEC_HEADER_SIZE
)
318 magic
= read_u32(buf
);
319 if (magic
!= FEC_MAGIC
)
320 return -E_BAD_FEC_HEADER
;
321 h
->slices_per_group
= read_u8(buf
+ 4);
322 h
->data_slices_per_group
= read_u8(buf
+ 5);
323 h
->audio_header_size
= read_u32(buf
+ 6);
325 h
->group_num
= read_u32(buf
+ 10);
326 h
->group_bytes
= read_u32(buf
+ 14);
328 h
->slice_num
= read_u8(buf
+ 18);
329 h
->slice_bytes
= read_u16(buf
+ 20);
330 h
->bos
= read_u8(buf
+ 22);
331 h
->header_stream
= read_u8(buf
+ 23);
332 if (!memcmp(buf
, FEC_EOF_PACKET
, FEC_EOF_PACKET_LEN
))
333 return -E_FECDEC_EOF
;
334 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
335 // h->group_num, h->slice_num, h->slices_per_group);
339 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
340 static int dispatch_slice(char *buf
, size_t len
, struct fec_header
*h
,
341 struct filter_node
*fn
)
343 struct fecdec_group
*fg
;
345 struct private_fecdec_data
*pfd
= fn
->private_data
;
347 if (h
->slice_bytes
> len
) /* can not use the thing, try to read more */
349 ret
= get_group(h
, pfd
, &fg
);
352 if (!add_slice(buf
, fg
))
354 if (group_complete(fg
)) {
356 int k
= h
->data_slices_per_group
, n
= h
->slices_per_group
;
357 PARA_NOTICE_LOG("init fec (%d, %d)\n", k
, n
);
358 ret
= fec_new(k
, n
, &pfd
->fec
);
362 ret
= decode_group(fg
, fn
);
369 static ssize_t
fecdec(char *buf
, size_t len
, struct filter_node
*fn
)
374 ret
= read_fec_header(buf
, len
, &h
);
378 return -E_BAD_SLICE_SIZE
;
379 if (h
.slice_num
> h
.slices_per_group
)
380 return -E_BAD_SLICE_NUM
;
381 ret
= dispatch_slice(buf
+ FEC_HEADER_SIZE
, len
- FEC_HEADER_SIZE
,
383 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
386 return FEC_HEADER_SIZE
+ h
.slice_bytes
;
389 static void fecdec_close(struct filter_node
*fn
)
391 struct private_fecdec_data
*pfd
= fn
->private_data
;
392 struct fecdec_group
*fg
;
394 FOR_EACH_FECDEC_GROUP(fg
, pfd
)
399 free(fn
->private_data
);
400 fn
->private_data
= NULL
;
403 static void fecdec_open(struct filter_node
*fn
)
405 fn
->bufsize
= FECDEC_DEFAULT_OUTBUF_SIZE
;
406 fn
->buf
= para_malloc(fn
->bufsize
);
407 fn
->private_data
= para_calloc(sizeof(struct private_fecdec_data
));
412 * The init function of the fecdec filter.
414 * \param f struct to initialize.
416 void fecdec_filter_init(struct filter
*f
)
419 f
->close
= fecdec_close
;
420 f
->open
= fecdec_open
;