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
= para_malloc(fg
->num_slices
* sizeof(int));
250 fg
->data
= para_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
] = para_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
,
265 FEC_GROUP_USABLE_WITH_HEADER
268 static enum fec_group_usability
group_is_usable(struct fecdec_group
*fg
,
269 struct private_fecdec_data
*pfd
)
271 struct fec_header
*h
= &fg
->h
;
273 if (!h
->header_stream
)
274 return FEC_GROUP_USABLE
;
275 if (pfd
->have_header
) {
276 if (h
->audio_header_size
)
277 return FEC_GROUP_USABLE_SKIP_HEADER
;
278 return FEC_GROUP_USABLE
;
281 return FEC_GROUP_USABLE
;
282 if (fg
->h
.audio_header_size
)
283 return FEC_GROUP_USABLE_WITH_HEADER
;
284 return FEC_GROUP_UNUSABLE
;
287 static int decode_group(struct fecdec_group
*fg
, struct filter_node
*fn
)
289 int i
, ret
, sb
= fg
->h
.slice_bytes
;
290 size_t written
, need
;
291 struct private_fecdec_data
*pfd
= fn
->private_data
;
292 enum fec_group_usability u
= group_is_usable(fg
, pfd
);
294 if (u
== FEC_GROUP_UNUSABLE
) {
295 PARA_INFO_LOG("dropping unusable group %d\n", fg
->h
.group_num
);
298 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg
->h
.group_num
,
299 fg
->h
.data_slices_per_group
);
300 ret
= fec_decode(pfd
->fec
, fg
->data
, fg
->idx
, sb
);
303 pfd
->have_header
= 1;
305 if (u
== FEC_GROUP_USABLE_SKIP_HEADER
) {
306 i
= ROUND_UP(fg
->h
.audio_header_size
, fg
->h
.slice_bytes
)
308 PARA_DEBUG_LOG("skipping %d header slices\n", i
);
310 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
311 fg
->h
.group_num
, fg
->h
.group_bytes
,
312 fg
->h
.data_slices_per_group
* sb
);
313 need
= fn
->loaded
+ (fg
->h
.data_slices_per_group
- i
)* sb
;
314 if (need
> fn
->bufsize
) {
315 fn
->bufsize
= PARA_MAX(fn
->bufsize
* 2, need
);
316 if (fn
->bufsize
> FECDEC_MAX_OUTBUF_SIZE
)
317 return -E_FECDEC_OVERRUN
;
318 PARA_INFO_LOG("increasing fec buf to %zu\n", fn
->bufsize
);
319 fn
->buf
= para_realloc(fn
->buf
, fn
->bufsize
);
321 if (u
== FEC_GROUP_USABLE_WITH_HEADER
) {
322 PARA_INFO_LOG("writing audio file header\n");
324 for (i
= 0; i
< fg
->h
.data_slices_per_group
; i
++) {
326 if (written
>= fg
->h
.audio_header_size
)
328 if (sb
+ written
> fg
->h
.audio_header_size
)
329 n
= fg
->h
.audio_header_size
- written
;
330 memcpy(fn
->buf
+ fn
->loaded
, fg
->data
[i
], n
);
336 for (; i
< fg
->h
.data_slices_per_group
; i
++) {
338 if (n
+ written
> fg
->h
.group_bytes
)
339 n
= fg
->h
.group_bytes
- written
;
340 memcpy(fn
->buf
+ fn
->loaded
, fg
->data
[i
], n
);
348 * Read a fec header from a buffer.
350 * \param buf The buffer to write to.
351 * \param h The fec header to write.
353 static int read_fec_header(char *buf
, size_t len
, struct fec_header
*h
)
357 if (len
< FEC_HEADER_SIZE
)
359 magic
= read_u32(buf
);
360 if (magic
!= FEC_MAGIC
)
361 return -E_BAD_FEC_HEADER
;
362 h
->slices_per_group
= read_u8(buf
+ 4);
363 h
->data_slices_per_group
= read_u8(buf
+ 5);
364 h
->audio_header_size
= read_u32(buf
+ 6);
366 h
->group_num
= read_u32(buf
+ 10);
367 h
->group_bytes
= read_u32(buf
+ 14);
369 h
->slice_num
= read_u8(buf
+ 18);
370 h
->slice_bytes
= read_u16(buf
+ 20);
371 h
->bos
= read_u8(buf
+ 22);
372 h
->header_stream
= read_u8(buf
+ 23);
373 if (!memcmp(buf
, FEC_EOF_PACKET
, FEC_EOF_PACKET_LEN
))
374 return -E_FECDEC_EOF
;
375 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
376 // h->group_num, h->slice_num, h->slices_per_group);
380 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
381 static int dispatch_slice(char *buf
, size_t len
, struct fec_header
*h
,
382 struct filter_node
*fn
)
384 struct fecdec_group
*fg
;
386 struct private_fecdec_data
*pfd
= fn
->private_data
;
388 if (h
->slice_bytes
> len
) /* can not use the thing, try to read more */
390 ret
= get_group(h
, pfd
, &fg
);
393 if (!add_slice(buf
, fg
))
395 if (group_complete(fg
)) {
396 if (pfd
->completion_status
== GCS_NO_COMPLETE_GROUP
) {
397 pfd
->completion_status
= GCS_FIRST_GROUP_COMPLETE
;
398 pfd
->first_complete_group
= fg
;
402 ret
= decode_group(fg
, fn
);
407 if (pfd
->completion_status
== GCS_NO_COMPLETE_GROUP
)
409 if (pfd
->completion_status
== GCS_FIRST_GROUP_DECODED
)
411 if (fg
== pfd
->first_complete_group
)
414 k
= h
->data_slices_per_group
;
415 n
= h
->slices_per_group
;
416 PARA_NOTICE_LOG("init fec (%d, %d)\n", k
, n
);
417 ret
= fec_new(k
, n
, &pfd
->fec
);
420 ret
= decode_group(pfd
->first_complete_group
, fn
);
423 pfd
->completion_status
= GCS_FIRST_GROUP_DECODED
;
427 static ssize_t
fecdec(char *buf
, size_t len
, struct filter_node
*fn
)
432 ret
= read_fec_header(buf
, len
, &h
);
436 return -E_BAD_SLICE_SIZE
;
437 if (h
.slice_num
> h
.slices_per_group
)
438 return -E_BAD_SLICE_NUM
;
439 ret
= dispatch_slice(buf
+ FEC_HEADER_SIZE
, len
- FEC_HEADER_SIZE
,
441 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
444 return FEC_HEADER_SIZE
+ h
.slice_bytes
;
447 static void fecdec_close(struct filter_node
*fn
)
449 struct private_fecdec_data
*pfd
= fn
->private_data
;
450 struct fecdec_group
*fg
;
452 FOR_EACH_FECDEC_GROUP(fg
, pfd
)
457 free(fn
->private_data
);
458 fn
->private_data
= NULL
;
461 static void fecdec_open(struct filter_node
*fn
)
463 struct private_fecdec_data
*pfd
;
464 fn
->bufsize
= FECDEC_DEFAULT_OUTBUF_SIZE
;
465 fn
->buf
= para_malloc(fn
->bufsize
);
466 pfd
= para_calloc(sizeof(*pfd
));
467 pfd
->completion_status
= GCS_NO_COMPLETE_GROUP
;
468 fn
->private_data
= pfd
;
473 * The init function of the fecdec filter.
475 * \param f struct to initialize.
477 void fecdec_filter_init(struct filter
*f
)
480 f
->close
= fecdec_close
;
481 f
->open
= fecdec_open
;