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 #include <stdbool.h>
  11
  12 #include <dirent.h>
  13 #include "para.h"
  14 #include "error.h"
  15 #include "list.h"
  16 #include "sched.h"
  17 #include "ggo.h"
  18 #include "buffer_tree.h"
  19 #include "filter.h"
  20 #include "string.h"
  21 #include "portable_io.h"
  22 #include "fec.h"
  23 #include "fd.h"
  24
  25 /**
  26  * How many FEC groups to store in memory.
  27  *
  28  * Packet reordering requires to keep more than one FEC group in memory because
  29  * slices belonging to the next FEC group may arrive before the current FEC group
  30  * is complete.
  31  */
  32 #define NUM_FEC_GROUPS 3
  33
  34 /** Data read from the header of a slice. */
  35 struct fec_header {
  36         /** Total number of slices in this group. */
  37         uint8_t slices_per_group;
  38         /** Number of slices needed to start decoding. */
  39         uint8_t data_slices_per_group;
  40         /** Size of the ogg vorbis/wma header (zero for mp3, aac). */
  41         uint32_t audio_header_size;
  42         /** Number of the FEC group this slice belongs to. */
  43         uint32_t group_num;
  44         /** Size of the data in this FEC group. */
  45         uint32_t group_bytes;
  46         /** Number of this slice in the group. */
  47         uint8_t slice_num;
  48         /** Used data bytes of this slice. */
  49         uint16_t slice_bytes;
  50         /** Non-zero if this group is the beginning of the stream. */
  51         uint8_t bos;
  52         /** Non-zero if this stream embedds audio headers into fec groups. */
  53         uint8_t header_stream;
  54 };
  55
  56 /**
  57  * The status of one partially received FEC group.
  58  */
  59 struct fecdec_group {
  60         /** The header read from the last slice. */
  61         struct fec_header h;
  62         /** How many slices received so far. */
  63         int num_received_slices;
  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                 fg->data[i] = NULL;
 108                 fg->idx[i] = -1;
 109         }
 110         free(fg->data);
 111         fg->data = NULL;
 112         free(fg->idx);
 113         fg->idx = NULL;
 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 /**
 247  * The different states of a complete FEC group.
 248  *
 249  * Even if a FEC group has been received successfully, it probably can not be
 250  * used right away because some streams (ogg, wma) need to receive an audio
 251  * file header before decoding can start.
 252  */
 253 enum fec_group_usability {
 254         /** Drop the group (because we did not receive the header yet). */
 255         FEC_GROUP_UNUSABLE,
 256         /** Use all data in the group. */
 257         FEC_GROUP_USABLE,
 258         /** Use the group, but drop its audio file header. */
 259         FEC_GROUP_USABLE_SKIP_HEADER,
 260         /** Use the group, including its header. */
 261         FEC_GROUP_USABLE_WITH_HEADER
 262 };
 263
 264 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 265                 struct private_fecdec_data *pfd)
 266 {
 267         struct fec_header *h = &fg->h;
 268
 269         if (!h->header_stream)
 270                 return FEC_GROUP_USABLE;
 271         if (pfd->have_header) {
 272                 if (h->audio_header_size)
 273                         return FEC_GROUP_USABLE_SKIP_HEADER;
 274                 return FEC_GROUP_USABLE;
 275         }
 276         if (fg->h.bos)
 277                 return FEC_GROUP_USABLE;
 278         if (fg->h.audio_header_size)
 279                 return FEC_GROUP_USABLE_WITH_HEADER;
 280         return FEC_GROUP_UNUSABLE;
 281 }
 282
 283 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 284 {
 285         int i, ret, sb = fg->h.slice_bytes;
 286         size_t written, need;
 287         struct private_fecdec_data *pfd = fn->private_data;
 288         enum fec_group_usability u = group_is_usable(fg, pfd);
 289         char *buf = NULL, *p;
 290
 291         if (u == FEC_GROUP_UNUSABLE) {
 292                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 293                 return 0;
 294         }
 295         PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
 296                 fg->h.data_slices_per_group);
 297         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 298         if (ret < 0)
 299                 return ret;
 300         pfd->have_header = 1;
 301         i = 0;
 302         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 303                 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
 304                         / fg->h.slice_bytes;
 305                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 306         }
 307         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 308                 fg->h.group_num, fg->h.group_bytes,
 309                 fg->h.data_slices_per_group * sb);
 310         need = (fg->h.data_slices_per_group - i) * sb;
 311         if (need > btr_pool_unused(pfd->btrp))
 312                 return -E_FECDEC_OVERRUN;
 313         btr_pool_get_buffer(pfd->btrp, &buf);
 314         p = buf;
 315         if (u == FEC_GROUP_USABLE_WITH_HEADER) {
 316                 PARA_INFO_LOG("writing audio file header\n");
 317                 written = 0;
 318                 for (i = 0; i < fg->h.data_slices_per_group; i++) {
 319                         size_t n = sb;
 320                         if (written >= fg->h.audio_header_size)
 321                                 break;
 322                         if (sb + written > fg->h.audio_header_size)
 323                                 n = fg->h.audio_header_size - written;
 324                         btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
 325                         written += n;
 326                 }
 327                 p += written;
 328         }
 329         written = 0;
 330         for (; i < fg->h.data_slices_per_group; i++) {
 331                 size_t n = sb;
 332                 if (n + written > fg->h.group_bytes)
 333                         n = fg->h.group_bytes - written;
 334                 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
 335                 written += n;
 336         }
 337         p += written;
 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", 20 * k *  h->slice_bytes);
 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         free(fn->private_data);
 435         fn->private_data = NULL;
 436 }
 437
 438 static void fecdec_post_select(__a_unused struct sched *s, struct task *t)
 439 {
 440         struct filter_node *fn = container_of(t, struct filter_node, task);
 441         struct btr_node *btrn = fn->btrn;
 442         int ret;
 443         struct fec_header h;
 444         char *buf;
 445         size_t len;
 446
 447 next_buffer:
 448         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 449         if (ret <= 0)
 450                 goto out;
 451         btr_merge(btrn, fn->min_iqs);
 452         len = btr_next_buffer(btrn, &buf);
 453         ret = read_fec_header(buf, len, &h);
 454         if (ret <= 0)
 455                 goto out;
 456         ret = -E_BAD_SLICE_SIZE;
 457         if (!h.slice_bytes)
 458                 goto out;
 459         ret = -E_BAD_SLICE_NUM;
 460         if (h.slice_num > h.slices_per_group)
 461                 goto out;
 462         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 463                 &h, fn);
 464         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 465         if (ret <= 0)
 466                 goto out;
 467         btr_consume(btrn, FEC_HEADER_SIZE + h.slice_bytes);
 468         goto next_buffer;
 469 out:
 470         t->error = ret;
 471         if (ret < 0)
 472                 btr_remove_node(btrn);
 473 }
 474
 475 static void fecdec_open(struct filter_node *fn)
 476 {
 477         struct private_fecdec_data *pfd;
 478         pfd = para_calloc(sizeof(*pfd));
 479         fn->private_data = pfd;
 480         fn->min_iqs = FEC_HEADER_SIZE;
 481 }
 482
 483 /**
 484  * The init function of the fecdec filter.
 485  *
 486  * \param f Struct to initialize.
 487  */
 488 void fecdec_filter_init(struct filter *f)
 489 {
 490         f->close = fecdec_close;
 491         f->open = fecdec_open;
 492         f->pre_select = generic_filter_pre_select;
 493         f->post_select = fecdec_post_select;
 494 }