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. */
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 * The fecdec filter defers decoding of the first group until the first slice
77 * of the next group was received. This avoids buffer underruns in subsequent
78 * filters of the filter chain.
80 enum group_completion_status
{
81 /** No complete group received so far. */
82 GCS_NO_COMPLETE_GROUP
,
83 /** First group received, but not yet decoded. */
84 GCS_FIRST_GROUP_COMPLETE
,
85 /** At least one complete group decoded. */
86 GCS_FIRST_GROUP_DECODED
,
90 * Data private to the fecdec filter.
92 struct private_fecdec_data
{
93 /** Used by the fec core code. */
94 struct fec_parms
*fec
;
95 /** Keeps track of what was received so far. */
96 struct fecdec_group groups
[NUM_FEC_GROUPS
];
97 /** Whether an audio file header was already received. */
99 /** See \ref group_completion_status. */
100 unsigned completion_status
;
101 /** Points to the first received group. */
102 struct fecdec_group
*first_complete_group
;
105 /** Iterate over all fecdec groups. */
106 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
107 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
109 static int group_complete(struct fecdec_group
*fg
)
111 return fg
->num_received_slices
>= fg
->h
.data_slices_per_group
;
114 static int group_empty(struct fecdec_group
*fg
)
116 return fg
->num_received_slices
== 0;
119 static void clear_group(struct fecdec_group
*fg
)
123 for (i
= 0; i
< fg
->num_slices
; i
++) {
131 memset(&fg
->h
, 0, sizeof(struct fec_header
));
132 fg
->num_received_slices
= 0;
135 static int find_group(struct fec_header
*h
,
136 struct private_fecdec_data
*pfd
, struct fecdec_group
**result
)
138 struct fecdec_group
*fg
;
140 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
141 if (fg
->h
.group_num
!= h
->group_num
)
143 if (fg
->num_received_slices
== 0)
145 if (fg
->h
.slices_per_group
!= h
->slices_per_group
)
146 return -E_BAD_FEC_HEADER
;
147 if (fg
->h
.data_slices_per_group
!= h
->data_slices_per_group
)
148 return -E_BAD_FEC_HEADER
;
149 if (fg
->h
.group_bytes
!= h
->group_bytes
)
150 return -E_BAD_FEC_HEADER
;
158 static struct fecdec_group
*find_unused_group(struct private_fecdec_data
*pfd
)
160 struct fecdec_group
*fg
;
162 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
163 if (fg
->num_received_slices
== 0)
169 static struct fecdec_group
*try_to_free_group(struct private_fecdec_data
*pfd
)
171 struct fecdec_group
*fg
;
173 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
174 if (!group_complete(fg
))
177 * Don't clear the first complete group if it has not yet been
180 if (pfd
->completion_status
== GCS_FIRST_GROUP_COMPLETE
181 && pfd
->first_complete_group
== fg
)
189 static struct fecdec_group
*free_oldest_group(struct private_fecdec_data
*pfd
)
191 struct fecdec_group
*fg
, *oldest
= NULL
;
193 FOR_EACH_FECDEC_GROUP(fg
, pfd
) {
194 if (!oldest
|| oldest
->h
.group_num
> fg
->h
.group_num
)
197 if (!group_complete(oldest
) && !group_empty(oldest
))
198 PARA_WARNING_LOG("Clearing incomplete group %d "
199 "(contains %d slices)\n", oldest
->h
.group_num
,
200 oldest
->num_received_slices
);
201 assert(pfd
->completion_status
!= GCS_FIRST_GROUP_COMPLETE
202 || oldest
!= pfd
->first_complete_group
);
207 /* returns 1 if the group was found, 0 if not, negative on errors */
208 static int get_group(struct fec_header
*h
, struct private_fecdec_data
*pfd
,
209 struct fecdec_group
**result
)
211 struct fecdec_group
*fg
;
212 int ret
= find_group(h
, pfd
, &fg
);
216 if (ret
> 0) /* found group */
218 /* group not found */
219 fg
= find_unused_group(pfd
);
222 fg
= try_to_free_group(pfd
);
225 fg
= free_oldest_group(pfd
);
234 * returns 1 if slice was added, zero otherwise (because the group was already
235 * complete). In any case the number of received slices is being increased by
238 static int add_slice(char *buf
, struct fecdec_group
*fg
)
242 if (group_complete(fg
)) {
243 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
244 fg
->h
.group_num
, fg
->h
.slice_num
);
245 fg
->num_received_slices
++;
248 slice_num
= fg
->h
.slice_num
;
249 if (fg
->num_slices
== 0) {
250 fg
->num_slices
= fg
->h
.slices_per_group
;
251 fg
->idx
= malloc(fg
->num_slices
* sizeof(int));
252 fg
->data
= malloc(fg
->num_slices
* sizeof(unsigned char *));
253 memset(fg
->data
, 0, fg
->num_slices
* sizeof(unsigned char *));
255 r
= fg
->num_received_slices
;
256 fg
->idx
[r
] = slice_num
;
257 fg
->data
[r
] = malloc(fg
->h
.slice_bytes
);
258 memcpy(fg
->data
[r
], buf
, fg
->h
.slice_bytes
);
259 fg
->num_received_slices
++;
263 enum fec_group_usability
{
266 FEC_GROUP_USABLE_SKIP_HEADER
,
269 static enum fec_group_usability
group_is_usable(struct fecdec_group
*fg
,
270 struct private_fecdec_data
*pfd
)
272 struct fec_header
*h
= &fg
->h
;
274 if (!h
->header_stream
)
275 return FEC_GROUP_USABLE
;
276 if (pfd
->have_header
) {
277 if (h
->audio_header_size
)
278 return FEC_GROUP_USABLE_SKIP_HEADER
;
279 return FEC_GROUP_USABLE
;
282 return FEC_GROUP_USABLE
;
283 if (fg
->h
.audio_header_size
)
284 return FEC_GROUP_USABLE
;
285 return FEC_GROUP_UNUSABLE
;
288 static int decode_group(struct fecdec_group
*fg
, struct filter_node
*fn
)
290 int i
, ret
, sb
= fg
->h
.slice_bytes
;
291 size_t written
= 0, need
;
292 struct private_fecdec_data
*pfd
= fn
->private_data
;
293 enum fec_group_usability u
= group_is_usable(fg
, pfd
);
295 if (u
== FEC_GROUP_UNUSABLE
) {
296 PARA_INFO_LOG("dropping unusable group %d\n", fg
->h
.group_num
);
299 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg
->h
.group_num
,
300 fg
->h
.data_slices_per_group
);
301 ret
= fec_decode(pfd
->fec
, fg
->data
, fg
->idx
, sb
);
304 pfd
->have_header
= 1;
306 if (u
== FEC_GROUP_USABLE_SKIP_HEADER
) {
307 i
= ROUND_UP(fg
->h
.audio_header_size
, fg
->h
.slice_bytes
)
309 PARA_DEBUG_LOG("skipping %d header slices\n", i
);
311 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
312 fg
->h
.group_num
, fg
->h
.group_bytes
,
313 fg
->h
.data_slices_per_group
* sb
);
314 need
= fn
->loaded
+ (fg
->h
.data_slices_per_group
- i
)* sb
;
315 if (need
> fn
->bufsize
) {
316 fn
->bufsize
= PARA_MAX(fn
->bufsize
* 2, need
);
317 if (fn
->bufsize
> FECDEC_MAX_OUTBUF_SIZE
)
318 return -E_FECDEC_OVERRUN
;
319 PARA_INFO_LOG("increasing fec buf to %zu\n", fn
->bufsize
);
320 fn
->buf
= para_realloc(fn
->buf
, fn
->bufsize
);
322 for (; i
< fg
->h
.data_slices_per_group
; i
++) {
324 if (n
+ written
> fg
->h
.group_bytes
)
325 n
= fg
->h
.group_bytes
- written
;
326 memcpy(fn
->buf
+ fn
->loaded
, fg
->data
[i
], n
);
334 * Read a fec header from a buffer.
336 * \param buf The buffer to write to.
337 * \param h The fec header to write.
339 static int read_fec_header(char *buf
, size_t len
, struct fec_header
*h
)
343 if (len
< FEC_HEADER_SIZE
)
345 magic
= read_u32(buf
);
346 if (magic
!= FEC_MAGIC
)
347 return -E_BAD_FEC_HEADER
;
348 h
->slices_per_group
= read_u8(buf
+ 4);
349 h
->data_slices_per_group
= read_u8(buf
+ 5);
350 h
->audio_header_size
= read_u32(buf
+ 6);
352 h
->group_num
= read_u32(buf
+ 10);
353 h
->group_bytes
= read_u32(buf
+ 14);
355 h
->slice_num
= read_u8(buf
+ 18);
356 h
->slice_bytes
= read_u16(buf
+ 20);
357 h
->bos
= read_u8(buf
+ 22);
358 h
->header_stream
= read_u8(buf
+ 23);
359 if (!memcmp(buf
, FEC_EOF_PACKET
, FEC_EOF_PACKET_LEN
))
360 return -E_FECDEC_EOF
;
361 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
362 // h->group_num, h->slice_num, h->slices_per_group);
366 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
367 static int dispatch_slice(char *buf
, size_t len
, struct fec_header
*h
,
368 struct filter_node
*fn
)
370 struct fecdec_group
*fg
;
372 struct private_fecdec_data
*pfd
= fn
->private_data
;
374 if (h
->slice_bytes
> len
) /* can not use the thing, try to read more */
376 ret
= get_group(h
, pfd
, &fg
);
379 if (!add_slice(buf
, fg
))
381 if (group_complete(fg
)) {
382 if (pfd
->completion_status
== GCS_NO_COMPLETE_GROUP
) {
383 pfd
->completion_status
= GCS_FIRST_GROUP_COMPLETE
;
384 pfd
->first_complete_group
= fg
;
388 ret
= decode_group(fg
, fn
);
393 if (pfd
->completion_status
== GCS_NO_COMPLETE_GROUP
)
395 if (pfd
->completion_status
== GCS_FIRST_GROUP_DECODED
)
397 if (fg
== pfd
->first_complete_group
)
400 k
= h
->data_slices_per_group
;
401 n
= h
->slices_per_group
;
402 PARA_NOTICE_LOG("init fec (%d, %d)\n", k
, n
);
403 ret
= fec_new(k
, n
, &pfd
->fec
);
406 ret
= decode_group(pfd
->first_complete_group
, fn
);
409 pfd
->completion_status
= GCS_FIRST_GROUP_DECODED
;
413 static ssize_t
fecdec(char *buf
, size_t len
, struct filter_node
*fn
)
418 ret
= read_fec_header(buf
, len
, &h
);
422 return -E_BAD_SLICE_SIZE
;
423 if (h
.slice_num
> h
.slices_per_group
)
424 return -E_BAD_SLICE_NUM
;
425 ret
= dispatch_slice(buf
+ FEC_HEADER_SIZE
, len
- FEC_HEADER_SIZE
,
427 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
430 return FEC_HEADER_SIZE
+ h
.slice_bytes
;
433 static void fecdec_close(struct filter_node
*fn
)
435 struct private_fecdec_data
*pfd
= fn
->private_data
;
436 struct fecdec_group
*fg
;
438 FOR_EACH_FECDEC_GROUP(fg
, pfd
)
443 free(fn
->private_data
);
444 fn
->private_data
= NULL
;
447 static void fecdec_open(struct filter_node
*fn
)
449 struct private_fecdec_data
*pfd
;
450 fn
->bufsize
= FECDEC_DEFAULT_OUTBUF_SIZE
;
451 fn
->buf
= para_malloc(fn
->bufsize
);
452 pfd
= para_calloc(sizeof(*pfd
));
453 pfd
->completion_status
= GCS_NO_COMPLETE_GROUP
;
454 fn
->private_data
= pfd
;
459 * The init function of the fecdec filter.
461 * \param f struct to initialize.
463 void fecdec_filter_init(struct filter
*f
)
466 f
->close
= fecdec_close
;
467 f
->open
= fecdec_open
;