fecdec_filter.c

   1 /*
   2  * Copyright (C) 2009-2012 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 "para.h"
  12 #include "error.h"
  13 #include "list.h"
  14 #include "sched.h"
  15 #include "ggo.h"
  16 #include "buffer_tree.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 /** Data read from the header of a slice. */
  33 struct fec_header {
  34         /** Total number of slices in this group. */
  35         uint8_t slices_per_group;
  36         /** Number of slices needed to start decoding. */
  37         uint8_t data_slices_per_group;
  38         /** Size of the ogg vorbis/wma header (zero for mp3, aac). */
  39         uint32_t audio_header_size;
  40         /** Number of the FEC group this slice belongs to. */
  41         uint32_t group_num;
  42         /** Size of the data in this FEC group. */
  43         uint32_t group_bytes;
  44         /** Number of this slice in the group. */
  45         uint8_t slice_num;
  46         /** Used data bytes of this slice. */
  47         uint16_t slice_bytes;
  48         /** Non-zero if this group is the beginning of the stream. */
  49         uint8_t bos;
  50         /** Non-zero if this stream embedds audio headers into fec groups. */
  51         uint8_t header_stream;
  52 };
  53
  54 /**
  55  * The status of one partially received FEC group.
  56  */
  57 struct fecdec_group {
  58         /** The header read from the last slice. */
  59         struct fec_header h;
  60         /** How many slices received so far. */
  61         int num_received_slices;
  62         /** Bitmap of received slices. */
  63         uint8_t received_slices[32];
  64         /** The size of the \a idx and the \a data arrays below. */
  65         int num_slices;
  66         /** Array of indices of the received slices. */
  67         int *idx;
  68         /** Content of the received slices. */
  69         unsigned char **data;
  70 };
  71
  72 /**
  73  * Data private to the fecdec filter.
  74  */
  75 struct private_fecdec_data {
  76         /** Used by the fec core code. */
  77         struct fec_parms *fec;
  78         /** Keeps track of what was received so far. */
  79         struct fecdec_group groups[NUM_FEC_GROUPS];
  80         /** Whether an audio file header was already received. */
  81         int have_header;
  82         /** Points to the first received group. */
  83         struct fecdec_group *first_complete_group;
  84         struct btr_pool *btrp;
  85 };
  86
  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)++)
  90
  91 static int group_complete(struct fecdec_group *fg)
  92 {
  93         return fg->num_received_slices >= fg->h.data_slices_per_group;
  94 }
  95
  96 static int group_empty(struct fecdec_group *fg)
  97 {
  98         return fg->num_received_slices == 0;
  99 }
 100
 101 static void clear_group(struct fecdec_group *fg)
 102 {
 103         int i;
 104
 105         for (i = 0; i < fg->num_slices; i++)
 106                 free(fg->data[i]);
 107         free(fg->data);
 108         free(fg->idx);
 109         memset(fg, 0, sizeof(*fg));
 110 }
 111
 112 static int find_group(struct fec_header *h,
 113                 struct private_fecdec_data *pfd, struct fecdec_group **result)
 114 {
 115         struct fecdec_group *fg;
 116
 117         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 118                 if (fg->h.group_num != h->group_num)
 119                         continue;
 120                 if (fg->num_received_slices == 0)
 121                         goto success;
 122                 if (fg->h.slices_per_group != h->slices_per_group)
 123                         return -E_BAD_FEC_HEADER;
 124                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 125                         return -E_BAD_FEC_HEADER;
 126                 if (fg->h.group_bytes != h->group_bytes)
 127                         return -E_BAD_FEC_HEADER;
 128 success:
 129                 *result = fg;
 130                 return 1;
 131         }
 132         return 0;
 133 }
 134
 135 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 136 {
 137         struct fecdec_group *fg;
 138
 139         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 140                 if (fg->num_received_slices == 0)
 141                         return fg;
 142         }
 143         return NULL;
 144 }
 145
 146 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 147 {
 148         struct fecdec_group *fg;
 149
 150         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 151                 if (!group_complete(fg))
 152                         continue;
 153                 /*
 154                  * Don't clear the first complete group if it has not yet been
 155                  * decoded.
 156                  */
 157                 if (fg == pfd->first_complete_group)
 158                         continue;
 159                 clear_group(fg);
 160                 return fg;
 161         }
 162         return NULL;
 163 }
 164
 165 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 166 {
 167         struct fecdec_group *fg, *oldest = NULL;
 168
 169         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 170                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 171                         oldest = fg;
 172         }
 173         if (!group_complete(oldest) && !group_empty(oldest))
 174                 PARA_WARNING_LOG("Clearing incomplete group %d "
 175                         "(contains %d slices)\n", oldest->h.group_num,
 176                         oldest->num_received_slices);
 177         if (oldest == pfd->first_complete_group)
 178                 pfd->first_complete_group = NULL;
 179         clear_group(oldest);
 180         return oldest;
 181 }
 182
 183 /* returns 1 if the group was found, 0 if not, negative on errors */
 184 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 185                 struct fecdec_group **result)
 186 {
 187         struct fecdec_group *fg;
 188         int ret = find_group(h, pfd, &fg);
 189
 190         if (ret < 0)
 191                 return ret;
 192         if (ret > 0) /* found group */
 193                 goto success;
 194         /* group not found */
 195         fg = find_unused_group(pfd);
 196         if (fg)
 197                 goto success;
 198         fg = try_to_free_group(pfd);
 199         if (fg)
 200                 goto success;
 201         fg = free_oldest_group(pfd);
 202         ret = 0;
 203 success:
 204         fg->h = *h;
 205         *result = fg;
 206         return ret;
 207 }
 208
 209 static bool test_and_set_slice_bit(struct fecdec_group *fg, uint8_t slice_num)
 210 {
 211         uint8_t *p = fg->received_slices + slice_num / 8, old = *p;
 212
 213         *p |= 1 << (slice_num % 8);
 214         return old == *p;
 215 }
 216
 217 /*
 218  * returns 1 if slice was added, zero otherwise (because the group was already
 219  * complete or a slice has been received twice).
 220  */
 221 static int add_slice(char *buf, struct fecdec_group *fg)
 222 {
 223         int r;
 224         uint8_t slice_num = fg->h.slice_num;
 225
 226         if (group_complete(fg)) {
 227                 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
 228                         fg->h.group_num, slice_num);
 229                 return 0;
 230         }
 231         if (fg->num_slices == 0) {
 232                 fg->num_slices = fg->h.slices_per_group;
 233                 fg->idx = para_malloc(fg->num_slices * sizeof(int));
 234                 fg->data = para_calloc(fg->num_slices * sizeof(unsigned char *));
 235         }
 236         r = fg->num_received_slices;
 237         /* Check if we already have this slice. */
 238         if (test_and_set_slice_bit(fg, slice_num)) {
 239                 PARA_INFO_LOG("ignoring duplicate slice %d:%d\n", fg->h.group_num,
 240                         slice_num);
 241                 return 0;
 242         }
 243         fg->idx[r] = slice_num;
 244         fg->data[r] = para_malloc(fg->h.slice_bytes);
 245         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 246         fg->num_received_slices++;
 247         return 1;
 248 }
 249
 250 /**
 251  * The different states of a complete FEC group.
 252  *
 253  * Even if a FEC group has been received successfully, it probably can not be
 254  * used right away because some streams (ogg, wma) need to receive an audio
 255  * file header before decoding can start.
 256  */
 257 enum fec_group_usability {
 258         /** Drop the group (because we did not receive the header yet). */
 259         FEC_GROUP_UNUSABLE,
 260         /** Use all data in the group. */
 261         FEC_GROUP_USABLE,
 262         /** Use the group, but drop its audio file header. */
 263         FEC_GROUP_USABLE_SKIP_HEADER,
 264         /** Use the group, including its header. */
 265         FEC_GROUP_USABLE_WITH_HEADER
 266 };
 267
 268 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 269                 struct private_fecdec_data *pfd)
 270 {
 271         struct fec_header *h = &fg->h;
 272
 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;
 279         }
 280         if (fg->h.bos)
 281                 return FEC_GROUP_USABLE;
 282         if (fg->h.audio_header_size)
 283                 return FEC_GROUP_USABLE_WITH_HEADER;
 284         return FEC_GROUP_UNUSABLE;
 285 }
 286
 287 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 288 {
 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);
 293         char *buf = NULL;
 294
 295         if (u == FEC_GROUP_UNUSABLE) {
 296                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 297                 return 0;
 298         }
 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);
 302         if (ret < 0)
 303                 return ret;
 304         pfd->have_header = 1;
 305         i = 0;
 306         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 307                 i = DIV_ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes);
 308                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 309         }
 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 = (fg->h.data_slices_per_group - i) * sb;
 314         if (need > btr_pool_unused(pfd->btrp))
 315                 return -E_FECDEC_OVERRUN;
 316         btr_pool_get_buffer(pfd->btrp, &buf);
 317         if (u == FEC_GROUP_USABLE_WITH_HEADER) {
 318                 PARA_INFO_LOG("writing audio file header\n");
 319                 written = 0;
 320                 for (i = 0; i < fg->h.data_slices_per_group; i++) {
 321                         size_t n = sb;
 322                         if (written >= fg->h.audio_header_size)
 323                                 break;
 324                         if (sb + written > fg->h.audio_header_size)
 325                                 n = fg->h.audio_header_size - written;
 326                         btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
 327                         written += n;
 328                 }
 329         }
 330         written = 0;
 331         for (; i < fg->h.data_slices_per_group; i++) {
 332                 size_t n = sb;
 333                 if (n + written > fg->h.group_bytes)
 334                         n = fg->h.group_bytes - written;
 335                 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
 336                 written += n;
 337         }
 338         return 0;
 339 }
 340
 341 /**
 342  * Read a fec header from a buffer.
 343  *
 344  * \param buf The buffer to write to.
 345  * \param h The fec header to write.
 346  */
 347 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 348 {
 349         uint32_t magic;
 350
 351         if (len < FEC_HEADER_SIZE)
 352                 return 0;
 353         magic = read_u32(buf);
 354         if (magic != FEC_MAGIC)
 355                 return -E_BAD_FEC_HEADER;
 356         h->slices_per_group = read_u8(buf + 4);
 357         h->data_slices_per_group = read_u8(buf + 5);
 358         h->audio_header_size = read_u32(buf + 6);
 359
 360         h->group_num = read_u32(buf + 10);
 361         h->group_bytes = read_u32(buf + 14);
 362
 363         h->slice_num = read_u8(buf + 18);
 364         h->slice_bytes = read_u16(buf + 20);
 365         h->bos = read_u8(buf + 22);
 366         h->header_stream = read_u8(buf + 23);
 367         if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 368                 return -E_FECDEC_EOF;
 369 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 370 //              h->group_num, h->slice_num, h->slices_per_group);
 371         return 1;
 372 }
 373
 374 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 375 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 376                 struct filter_node *fn)
 377 {
 378         struct fecdec_group *fg;
 379         int ret, k, n;
 380         struct private_fecdec_data *pfd = fn->private_data;
 381
 382         if (h->slice_bytes > len) { /* can not use the thing, try to read more */
 383                 fn->min_iqs = h->slice_bytes + FEC_HEADER_SIZE;
 384                 return 0;
 385         }
 386         ret = get_group(h, pfd, &fg);
 387         if (ret < 0)
 388                 return ret;
 389         if (!add_slice(buf, fg)) /* group already complete */
 390                 return 1;
 391         if (!group_complete(fg))
 392                 return 1;
 393         /* this slice completed the group */
 394         if (pfd->fec)
 395                 goto decode;
 396         /* it's either the first or the second complete group */
 397         if (!pfd->first_complete_group) { /* it's the first group */
 398                 enum fec_group_usability u = group_is_usable(fg, pfd);
 399                 assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
 400                 if (u == FEC_GROUP_UNUSABLE) /* forget it */
 401                         return 1;
 402                 pfd->first_complete_group = fg; /* remember it */
 403                 return 1;
 404         }
 405         /* we have two complete groups, let's go */
 406         k = h->data_slices_per_group;
 407         n = h->slices_per_group;
 408         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 409         ret = fec_new(k, n, &pfd->fec);
 410         if (ret < 0)
 411                 return ret;
 412         pfd->btrp = btr_pool_new("fecdec", 64 * 1024);
 413         /* decode and clear the first group */
 414         ret = decode_group(pfd->first_complete_group, fn);
 415         if (ret < 0)
 416                 return ret;
 417         clear_group(pfd->first_complete_group);
 418         pfd->first_complete_group = NULL;
 419 decode:
 420         ret = decode_group(fg, fn);
 421         if (ret < 0)
 422                 return ret;
 423         return 1;
 424 }
 425
 426 static void fecdec_close(struct filter_node *fn)
 427 {
 428         struct private_fecdec_data *pfd = fn->private_data;
 429         struct fecdec_group *fg;
 430
 431         FOR_EACH_FECDEC_GROUP(fg, pfd)
 432                 clear_group(fg);
 433         fec_free(pfd->fec);
 434         btr_pool_free(pfd->btrp);
 435         free(fn->private_data);
 436         fn->private_data = NULL;
 437 }
 438
 439 static void fecdec_post_select(__a_unused struct sched *s, struct task *t)
 440 {
 441         struct filter_node *fn = container_of(t, struct filter_node, task);
 442         struct btr_node *btrn = fn->btrn;
 443         int ret;
 444         struct fec_header h;
 445         char *buf;
 446         size_t len;
 447
 448 next_buffer:
 449         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 450         if (ret <= 0)
 451                 goto out;
 452         btr_merge(btrn, fn->min_iqs);
 453         len = btr_next_buffer(btrn, &buf);
 454         ret = read_fec_header(buf, len, &h);
 455         if (ret <= 0)
 456                 goto out;
 457         ret = -E_BAD_SLICE_SIZE;
 458         if (!h.slice_bytes)
 459                 goto out;
 460         ret = -E_BAD_SLICE_NUM;
 461         if (h.slice_num > h.slices_per_group)
 462                 goto out;
 463         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 464                 &h, fn);
 465         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 466         if (ret <= 0)
 467                 goto out;
 468         btr_consume(btrn, FEC_HEADER_SIZE + h.slice_bytes);
 469         goto next_buffer;
 470 out:
 471         t->error = ret;
 472         if (ret < 0)
 473                 btr_remove_node(btrn);
 474 }
 475
 476 static void fecdec_open(struct filter_node *fn)
 477 {
 478         struct private_fecdec_data *pfd;
 479         pfd = para_calloc(sizeof(*pfd));
 480         fn->private_data = pfd;
 481         fn->min_iqs = FEC_HEADER_SIZE;
 482 }
 483
 484 /**
 485  * The init function of the fecdec filter.
 486  *
 487  * \param f Struct to initialize.
 488  */
 489 void fecdec_filter_init(struct filter *f)
 490 {
 491         f->close = fecdec_close;
 492         f->open = fecdec_open;
 493         f->pre_select = generic_filter_pre_select;
 494         f->post_select = fecdec_post_select;
 495 }