fecdec_filter.c

   1 /*
   2  * Copyright (C) 2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file fecdec_filter.c A filter that fec-decodes an audio stream. */
   8
   9 #include <regex.h>
  10
  11 #include <dirent.h>
  12 #include "para.h"
  13 #include "error.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "ggo.h"
  17 #include "filter.h"
  18 #include "string.h"
  19 #include "portable_io.h"
  20 #include "fec.h"
  21 #include "fd.h"
  22
  23 /**
  24  * How many FEC groups to store in memory.
  25  *
  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
  28  * is complete.
  29  */
  30 #define NUM_FEC_GROUPS 3
  31
  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)
  36
  37 /** Data read from the header of a slice. */
  38 struct fec_header {
  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. */
  46         uint32_t group_num;
  47         /** Size of the data in this FEC group. */
  48         uint32_t group_bytes;
  49         /** Number of this slice in the group. */
  50         uint8_t slice_num;
  51         /** Used data bytes of this slice. */
  52         uint16_t slice_bytes;
  53         /** Non-zero if this group is the beginning of the stream. */
  54         uint8_t bos;
  55         /** Non-zero if this stream embedds audio headers into fec groups. */
  56         uint8_t header_stream;
  57 };
  58
  59 /**
  60  * The status of one partially received FEC group.
  61  */
  62 struct fecdec_group {
  63         /** The header read from the last slice. */
  64         struct fec_header h;
  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. */
  68         int num_slices;
  69         /** Array of indices of the received slices. */
  70         int *idx;
  71         /** Content of the received slices. */
  72         unsigned char **data;
  73 };
  74
  75 /**
  76  * Data private to the fecdec filter.
  77  */
  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. */
  84         int have_header;
  85         /** Points to the first received group. */
  86         struct fecdec_group *first_complete_group;
  87 };
  88
  89 /** Iterate over all fecdec groups. */
  90 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
  91         (g) < (d)->groups + NUM_FEC_GROUPS; (g)++)
  92
  93 static int group_complete(struct fecdec_group *fg)
  94 {
  95         return fg->num_received_slices >= fg->h.data_slices_per_group;
  96 }
  97
  98 static int group_empty(struct fecdec_group *fg)
  99 {
 100         return fg->num_received_slices == 0;
 101 }
 102
 103 static void clear_group(struct fecdec_group *fg)
 104 {
 105         int i;
 106
 107         for (i = 0; i < fg->num_slices; i++) {
 108                 free(fg->data[i]);
 109                 fg->data[i] = NULL;
 110                 fg->idx[i] = -1;
 111         }
 112         free(fg->data);
 113         free(fg->idx);
 114         fg->num_slices = 0;
 115         memset(&fg->h, 0, sizeof(struct fec_header));
 116         fg->num_received_slices = 0;
 117 }
 118
 119 static int find_group(struct fec_header *h,
 120                 struct private_fecdec_data *pfd, struct fecdec_group **result)
 121 {
 122         struct fecdec_group *fg;
 123
 124         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 125                 if (fg->h.group_num != h->group_num)
 126                         continue;
 127                 if (fg->num_received_slices == 0)
 128                         goto success;
 129                 if (fg->h.slices_per_group != h->slices_per_group)
 130                         return -E_BAD_FEC_HEADER;
 131                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 132                         return -E_BAD_FEC_HEADER;
 133                 if (fg->h.group_bytes != h->group_bytes)
 134                         return -E_BAD_FEC_HEADER;
 135 success:
 136                 *result = fg;
 137                 return 1;
 138         }
 139         return 0;
 140 }
 141
 142 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 143 {
 144         struct fecdec_group *fg;
 145
 146         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 147                 if (fg->num_received_slices == 0)
 148                         return fg;
 149         }
 150         return NULL;
 151 }
 152
 153 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 154 {
 155         struct fecdec_group *fg;
 156
 157         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 158                 if (!group_complete(fg))
 159                         continue;
 160                 /*
 161                  * Don't clear the first complete group if it has not yet been
 162                  * decoded.
 163                  */
 164                 if (fg == pfd->first_complete_group)
 165                         continue;
 166                 clear_group(fg);
 167                 return fg;
 168         }
 169         return NULL;
 170 }
 171
 172 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 173 {
 174         struct fecdec_group *fg, *oldest = NULL;
 175
 176         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 177                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 178                         oldest = fg;
 179         }
 180         if (!group_complete(oldest) && !group_empty(oldest))
 181                 PARA_WARNING_LOG("Clearing incomplete group %d "
 182                         "(contains %d slices)\n", oldest->h.group_num,
 183                         oldest->num_received_slices);
 184         if (oldest == pfd->first_complete_group)
 185                 pfd->first_complete_group = NULL;
 186         clear_group(oldest);
 187         return oldest;
 188 }
 189
 190 /* returns 1 if the group was found, 0 if not, negative on errors */
 191 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 192                 struct fecdec_group **result)
 193 {
 194         struct fecdec_group *fg;
 195         int ret = find_group(h, pfd, &fg);
 196
 197         if (ret < 0)
 198                 return ret;
 199         if (ret > 0) /* found group */
 200                 goto success;
 201         /* group not found */
 202         fg = find_unused_group(pfd);
 203         if (fg)
 204                 goto success;
 205         fg = try_to_free_group(pfd);
 206         if (fg)
 207                 goto success;
 208         fg = free_oldest_group(pfd);
 209         ret = 0;
 210 success:
 211         fg->h = *h;
 212         *result = fg;
 213         return ret;
 214 }
 215
 216 /*
 217  * returns 1 if slice was added, zero otherwise (because the group was already
 218  * complete). In any case the number of received slices is being increased by
 219  * one.
 220  */
 221 static int add_slice(char *buf, struct fecdec_group *fg)
 222 {
 223         int r, slice_num;
 224
 225         if (group_complete(fg)) {
 226                 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
 227                         fg->h.group_num, fg->h.slice_num);
 228                 fg->num_received_slices++;
 229                 return 0;
 230         }
 231         slice_num = fg->h.slice_num;
 232         if (fg->num_slices == 0) {
 233                 fg->num_slices = fg->h.slices_per_group;
 234                 fg->idx = para_malloc(fg->num_slices * sizeof(int));
 235                 fg->data = para_malloc(fg->num_slices * sizeof(unsigned char *));
 236                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 237         }
 238         r = fg->num_received_slices;
 239         fg->idx[r] = slice_num;
 240         fg->data[r] = para_malloc(fg->h.slice_bytes);
 241         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 242         fg->num_received_slices++;
 243         return 1;
 244 }
 245
 246 enum fec_group_usability {
 247         FEC_GROUP_UNUSABLE,
 248         FEC_GROUP_USABLE,
 249         FEC_GROUP_USABLE_SKIP_HEADER,
 250         FEC_GROUP_USABLE_WITH_HEADER
 251 };
 252
 253 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 254                 struct private_fecdec_data *pfd)
 255 {
 256         struct fec_header *h = &fg->h;
 257
 258         if (!h->header_stream)
 259                 return FEC_GROUP_USABLE;
 260         if (pfd->have_header) {
 261                 if (h->audio_header_size)
 262                         return FEC_GROUP_USABLE_SKIP_HEADER;
 263                 return FEC_GROUP_USABLE;
 264         }
 265         if (fg->h.bos)
 266                 return FEC_GROUP_USABLE;
 267         if (fg->h.audio_header_size)
 268                 return FEC_GROUP_USABLE_WITH_HEADER;
 269         return FEC_GROUP_UNUSABLE;
 270 }
 271
 272 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 273 {
 274         int i, ret, sb = fg->h.slice_bytes;
 275         size_t written, need;
 276         struct private_fecdec_data *pfd = fn->private_data;
 277         enum fec_group_usability u = group_is_usable(fg, pfd);
 278
 279         if (u == FEC_GROUP_UNUSABLE) {
 280                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 281                 return 0;
 282         }
 283         PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
 284                 fg->h.data_slices_per_group);
 285         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 286         if (ret < 0)
 287                 return ret;
 288         pfd->have_header = 1;
 289         i = 0;
 290         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 291                 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
 292                         / fg->h.slice_bytes;
 293                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 294         }
 295         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 296                 fg->h.group_num, fg->h.group_bytes,
 297                 fg->h.data_slices_per_group * sb);
 298         need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
 299         if (need > fn->bufsize) {
 300                 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
 301                 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
 302                         return -E_FECDEC_OVERRUN;
 303                 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
 304                 fn->buf = para_realloc(fn->buf, fn->bufsize);
 305         }
 306         if (u == FEC_GROUP_USABLE_WITH_HEADER) {
 307                 PARA_INFO_LOG("writing audio file header\n");
 308                 written = 0;
 309                 for (i = 0; i < fg->h.data_slices_per_group; i++) {
 310                         size_t n = sb;
 311                         if (written >= fg->h.audio_header_size)
 312                                 break;
 313                         if (sb + written > fg->h.audio_header_size)
 314                                 n = fg->h.audio_header_size - written;
 315                         memcpy(fn->buf + fn->loaded, fg->data[i], n);
 316                         fn->loaded += n;
 317                         written += n;
 318                 }
 319         }
 320         written = 0;
 321         for (; i < fg->h.data_slices_per_group; i++) {
 322                 size_t n = sb;
 323                 if (n + written > fg->h.group_bytes)
 324                         n = fg->h.group_bytes - written;
 325                 memcpy(fn->buf + fn->loaded, fg->data[i], n);
 326                 fn->loaded += n;
 327                 written += n;
 328         }
 329         return 0;
 330 }
 331
 332 /**
 333  * Read a fec header from a buffer.
 334  *
 335  * \param buf The buffer to write to.
 336  * \param h The fec header to write.
 337  */
 338 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 339 {
 340         uint32_t magic;
 341
 342         if (len < FEC_HEADER_SIZE)
 343                 return 0;
 344         magic = read_u32(buf);
 345         if (magic != FEC_MAGIC)
 346                 return -E_BAD_FEC_HEADER;
 347         h->slices_per_group = read_u8(buf + 4);
 348         h->data_slices_per_group = read_u8(buf + 5);
 349         h->audio_header_size = read_u32(buf + 6);
 350
 351         h->group_num = read_u32(buf + 10);
 352         h->group_bytes = read_u32(buf + 14);
 353
 354         h->slice_num = read_u8(buf + 18);
 355         h->slice_bytes = read_u16(buf + 20);
 356         h->bos = read_u8(buf + 22);
 357         h->header_stream = read_u8(buf + 23);
 358         if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 359                 return -E_FECDEC_EOF;
 360 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 361 //              h->group_num, h->slice_num, h->slices_per_group);
 362         return 1;
 363 }
 364
 365 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 366 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 367                 struct filter_node *fn)
 368 {
 369         struct fecdec_group *fg;
 370         int ret, k, n;
 371         struct private_fecdec_data *pfd = fn->private_data;
 372
 373         if (h->slice_bytes > len) /* can not use the thing, try to read more */
 374                 return 0;
 375         ret = get_group(h, pfd, &fg);
 376         if (ret < 0)
 377                 return ret;
 378         if (!add_slice(buf, fg)) /* group already complete */
 379                 return 1;
 380         if (!group_complete(fg))
 381                 return 1;
 382         /* this slice completed the group */
 383         if (pfd->fec)
 384                 goto decode;
 385         /* it's either the first or the second complete group */
 386         if (!pfd->first_complete_group) { /* it's the first group */
 387                 enum fec_group_usability u = group_is_usable(fg, pfd);
 388                 assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
 389                 if (u == FEC_GROUP_UNUSABLE) /* forget it */
 390                         return 1;
 391                 pfd->first_complete_group = fg; /* remember it */
 392                 return 1;
 393         }
 394         /* we have two complete groups, let's go */
 395         k = h->data_slices_per_group;
 396         n = h->slices_per_group;
 397         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 398         ret = fec_new(k, n, &pfd->fec);
 399         if (ret < 0)
 400                 return ret;
 401         /* decode and clear the first group */
 402         ret = decode_group(pfd->first_complete_group, fn);
 403         if (ret < 0)
 404                 return ret;
 405         clear_group(pfd->first_complete_group);
 406         pfd->first_complete_group = NULL;
 407 decode:
 408         ret = decode_group(fg, fn);
 409         if (ret < 0)
 410                 return ret;
 411         return 1;
 412 }
 413
 414 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
 415 {
 416         int ret;
 417         struct fec_header h;
 418
 419         ret = read_fec_header(buf, len, &h);
 420         if (ret <= 0)
 421                 return ret;
 422         if (!h.slice_bytes)
 423                 return -E_BAD_SLICE_SIZE;
 424         if (h.slice_num > h.slices_per_group)
 425                 return -E_BAD_SLICE_NUM;
 426         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 427                 &h, fn);
 428         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 429         if (ret <= 0)
 430                 return ret;
 431         return FEC_HEADER_SIZE + h.slice_bytes;
 432 }
 433
 434 static void fecdec_close(struct filter_node *fn)
 435 {
 436         struct private_fecdec_data *pfd = fn->private_data;
 437         struct fecdec_group *fg;
 438
 439         FOR_EACH_FECDEC_GROUP(fg, pfd)
 440                 clear_group(fg);
 441         free(fn->buf);
 442         fn->buf = NULL;
 443         fec_free(pfd->fec);
 444         free(fn->private_data);
 445         fn->private_data = NULL;
 446 }
 447
 448 static void fecdec_open(struct filter_node *fn)
 449 {
 450         struct private_fecdec_data *pfd;
 451         fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
 452         fn->buf = para_malloc(fn->bufsize);
 453         pfd = para_calloc(sizeof(*pfd));
 454         fn->private_data = pfd;
 455         fn->loaded = 0;
 456 }
 457
 458 /**
 459  * The init function of the fecdec filter.
 460  *
 461  * \param f struct to initialize.
 462  */
 463 void fecdec_filter_init(struct filter *f)
 464 {
 465         f->convert = fecdec;
 466         f->close = fecdec_close;
 467         f->open = fecdec_open;
 468 }