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 fec-decodes an audio stream. */
   8
   9 #include <dirent.h>
  10 #include "para.h"
  11 #include "error.h"
  12 #include "list.h"
  13 #include "sched.h"
  14 #include "ggo.h"
  15 #include "filter.h"
  16 #include "string.h"
  17 #include "portable_io.h"
  18 #include "fec.h"
  19 #include "fd.h"
  20
  21 /**
  22  * How many FEC groups to store in memory.
  23  *
  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
  26  * is complete.
  27  */
  28 #define NUM_FEC_GROUPS 3
  29
  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)
  34
  35 /** Data read from the header of a slice. */
  36 struct fec_header {
  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. */
  44         uint32_t group_num;
  45         /** Size of the data in this FEC group. */
  46         uint32_t group_bytes;
  47         /** Number of this slice in the group. */
  48         uint8_t slice_num;
  49         /** Used data bytes of this slice. */
  50         uint16_t slice_bytes;
  51         /** Non-zero if this group is the beginning of the stream. */
  52         uint8_t bos;
  53         /** Non-zero if this stream embedds audio headers into fec groups. */
  54         uint8_t header_stream;
  55 };
  56
  57 /**
  58  * The status of one partially received FEC group.
  59  */
  60 struct fecdec_group {
  61         /** The header read from the last slice. */
  62         struct fec_header h;
  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. */
  66         int num_slices;
  67         /** Array of indices of the received slices. */
  68         int *idx;
  69         /** Content of the received slices. */
  70         unsigned char **data;
  71 };
  72
  73 /**
  74  * Data private to the fecdec filter.
  75  */
  76 struct private_fecdec_data {
  77         /** Used by the fec core code. */
  78         struct fec_parms *fec;
  79         /** Keeps track of what was received so far. */
  80         struct fecdec_group groups[NUM_FEC_GROUPS];
  81         int have_header;
  82 };
  83
  84 /** Iterate over all fecdec groups. */
  85 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
  86         (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
  87
  88 static int group_complete(struct fecdec_group *fg)
  89 {
  90         return fg->num_received_slices >= fg->h.data_slices_per_group;
  91 }
  92
  93 static int group_empty(struct fecdec_group *fg)
  94 {
  95         return fg->num_received_slices == 0;
  96 }
  97
  98 static void clear_group(struct fecdec_group *fg)
  99 {
 100         int i;
 101
 102         for (i = 0; i < fg->num_slices; i++) {
 103                 free(fg->data[i]);
 104                 fg->data[i] = NULL;
 105                 fg->idx[i] = -1;
 106         }
 107         free(fg->data);
 108         free(fg->idx);
 109         fg->num_slices = 0;
 110         memset(&fg->h, 0, sizeof(struct fec_header));
 111         fg->num_received_slices = 0;
 112 }
 113
 114 static int find_group(struct fec_header *h,
 115                 struct private_fecdec_data *pfd, struct fecdec_group **result)
 116 {
 117         struct fecdec_group *fg;
 118
 119         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 120                 if (fg->h.group_num != h->group_num)
 121                         continue;
 122                 if (fg->num_received_slices == 0)
 123                         goto success;
 124                 if (fg->h.slices_per_group != h->slices_per_group)
 125                         return -E_BAD_FEC_HEADER;
 126                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 127                         return -E_BAD_FEC_HEADER;
 128                 if (fg->h.group_bytes != h->group_bytes)
 129                         return -E_BAD_FEC_HEADER;
 130 success:
 131                 *result = fg;
 132                 return 1;
 133         }
 134         return 0;
 135 }
 136
 137 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 138 {
 139         struct fecdec_group *fg;
 140
 141         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 142                 if (fg->num_received_slices == 0)
 143                         return fg;
 144         }
 145         return NULL;
 146 }
 147
 148 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 149 {
 150         struct fecdec_group *fg;
 151
 152         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 153                 if (!group_complete(fg))
 154                         continue;
 155                 clear_group(fg);
 156                 return fg;
 157         }
 158         return NULL;
 159 }
 160
 161 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 162 {
 163         struct fecdec_group *fg, *oldest = NULL;
 164
 165         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 166                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 167                         oldest = fg;
 168         }
 169         if (!group_complete(oldest) && !group_empty(oldest))
 170                 PARA_WARNING_LOG("Clearing incomplete group %d "
 171                         "(contains %d slices)\n", oldest->h.group_num,
 172                         oldest->num_received_slices);
 173         clear_group(oldest);
 174         return oldest;
 175 }
 176
 177 /* returns 1 if the group was found, 0 if not, negative on errors */
 178 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 179                 struct fecdec_group **result)
 180 {
 181         struct fecdec_group *fg;
 182         int ret = find_group(h, pfd, &fg);
 183
 184         if (ret < 0)
 185                 return ret;
 186         if (ret > 0) /* found group */
 187                 goto success;
 188         /* group not found */
 189         fg = find_unused_group(pfd);
 190         if (fg)
 191                 goto success;
 192         fg = try_to_free_group(pfd);
 193         if (fg)
 194                 goto success;
 195         fg = free_oldest_group(pfd);
 196         ret = 0;
 197 success:
 198         fg->h = *h;
 199         *result = fg;
 200         return ret;
 201 }
 202
 203 /*
 204  * returns 1 if slice was added, zero otherwise (because the group was already
 205  * complete). In any case the number of received slices is being increased by
 206  * one.
 207  */
 208 static int add_slice(char *buf, struct fecdec_group *fg)
 209 {
 210         int r, slice_num;
 211
 212         if (group_complete(fg)) {
 213                 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
 214                         fg->h.slice_num);
 215                 fg->num_received_slices++;
 216                 return 0;
 217         }
 218         slice_num = fg->h.slice_num;
 219         if (fg->num_slices == 0) {
 220                 fg->num_slices = fg->h.slices_per_group;
 221                 fg->idx = malloc(fg->num_slices * sizeof(int));
 222                 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
 223                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 224         }
 225         r = fg->num_received_slices;
 226         fg->idx[r] = slice_num;
 227         fg->data[r] = malloc(fg->h.slice_bytes);
 228         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 229         fg->num_received_slices++;
 230         return 1;
 231 }
 232
 233 enum fec_group_usability {
 234         FEC_GROUP_UNUSABLE,
 235         FEC_GROUP_USABLE,
 236         FEC_GROUP_USABLE_SKIP_HEADER,
 237 };
 238
 239 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 240                 struct private_fecdec_data *pfd)
 241 {
 242         struct fec_header *h = &fg->h;
 243
 244         if (!h->header_stream)
 245                 return FEC_GROUP_USABLE;
 246         if (pfd->have_header) {
 247                 if (h->audio_header_size)
 248                         return FEC_GROUP_USABLE_SKIP_HEADER;
 249                 return FEC_GROUP_USABLE;
 250         }
 251         if (fg->h.bos)
 252                 return FEC_GROUP_USABLE;
 253         if (fg->h.audio_header_size)
 254                 return FEC_GROUP_USABLE;
 255         return FEC_GROUP_UNUSABLE;
 256 }
 257
 258 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 259 {
 260         int i, ret, sb = fg->h.slice_bytes;
 261         size_t written = 0, need;
 262         struct private_fecdec_data *pfd = fn->private_data;
 263         enum fec_group_usability u = group_is_usable(fg, pfd);
 264
 265         if (u == FEC_GROUP_UNUSABLE) {
 266                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 267                 return 0;
 268         }
 269         PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
 270                 fg->h.data_slices_per_group);
 271         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 272         if (ret < 0)
 273                 return ret;
 274         pfd->have_header = 1;
 275         i = 0;
 276         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 277                 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
 278                         / fg->h.slice_bytes;
 279                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 280         }
 281         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 282                 fg->h.group_num, fg->h.group_bytes,
 283                 fg->h.data_slices_per_group * sb);
 284         need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
 285         if (need > fn->bufsize) {
 286                 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
 287                 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
 288                         return -E_FECDEC_OVERRUN;
 289                 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
 290                 fn->buf = para_realloc(fn->buf, fn->bufsize);
 291         }
 292         for (; i < fg->h.data_slices_per_group; i++) {
 293                 size_t n = sb;
 294                 if (n + written > fg->h.group_bytes)
 295                         n = fg->h.group_bytes - written;
 296                 memcpy(fn->buf + fn->loaded, fg->data[i], n);
 297                 fn->loaded += n;
 298                 written += n;
 299         }
 300         return 0;
 301 }
 302
 303 /**
 304  * Read a fec header from a buffer.
 305  *
 306  * \param buf The buffer to write to.
 307  * \param h The fec header to write.
 308  */
 309 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 310 {
 311         uint32_t magic;
 312
 313         if (len < FEC_HEADER_SIZE)
 314                 return 0;
 315         magic = read_u32(buf);
 316         if (magic != FEC_MAGIC)
 317                 return -E_BAD_FEC_HEADER;
 318         h->slices_per_group = read_u8(buf + 4);
 319         h->data_slices_per_group = read_u8(buf + 5);
 320         h->audio_header_size = read_u32(buf + 6);
 321
 322         h->group_num = read_u32(buf + 10);
 323         h->group_bytes = read_u32(buf + 14);
 324
 325         h->slice_num = read_u8(buf + 18);
 326         h->slice_bytes = read_u16(buf + 20);
 327         h->bos = read_u8(buf + 22);
 328         h->header_stream = read_u8(buf + 23);
 329         if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 330                 return -E_FECDEC_EOF;
 331 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 332 //              h->group_num, h->slice_num, h->slices_per_group);
 333         return 1;
 334 }
 335
 336 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 337 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 338                 struct filter_node *fn)
 339 {
 340         struct fecdec_group *fg;
 341         int ret;
 342         struct private_fecdec_data *pfd = fn->private_data;
 343
 344         if (h->slice_bytes > len) /* can not use the thing, try to read more */
 345                 return 0;
 346         ret = get_group(h, pfd, &fg);
 347         if (ret < 0)
 348                 return ret;
 349         if (!add_slice(buf, fg))
 350                 return 1;
 351         if (group_complete(fg)) {
 352                 if (!pfd->fec) {
 353                         int k = h->data_slices_per_group, n = h->slices_per_group;
 354                         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 355                         ret = fec_new(k, n, &pfd->fec);
 356                         if (ret < 0)
 357                                 return ret;
 358                 }
 359                 ret = decode_group(fg, fn);
 360                 if (ret < 0)
 361                         return ret;
 362         }
 363         return 1;
 364 }
 365
 366 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
 367 {
 368         int ret;
 369         struct fec_header h;
 370
 371         ret = read_fec_header(buf, len, &h);
 372         if (ret <= 0)
 373                 return ret;
 374         if (!h.slice_bytes || h.slice_bytes > fn->bufsize)
 375                 return -E_BAD_SLICE_SIZE;
 376         if (h.slice_num > h.slices_per_group)
 377                 return -E_BAD_SLICE_NUM;
 378         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 379                 &h, fn);
 380         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 381         if (ret <= 0)
 382                 return ret;
 383         return FEC_HEADER_SIZE + h.slice_bytes;
 384 }
 385
 386 static void fecdec_close(struct filter_node *fn)
 387 {
 388         struct private_fecdec_data *pfd = fn->private_data;
 389         struct fecdec_group *fg;
 390
 391         FOR_EACH_FECDEC_GROUP(fg, pfd)
 392                 clear_group(fg);
 393         free(fn->buf);
 394         fn->buf = NULL;
 395         fec_free(pfd->fec);
 396         free(fn->private_data);
 397         fn->private_data = NULL;
 398 }
 399
 400 static void fecdec_open(struct filter_node *fn)
 401 {
 402         fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
 403         fn->buf = para_malloc(fn->bufsize);
 404         fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
 405         fn->loaded = 0;
 406 }
 407
 408 /**
 409  * The init function of the fecdec filter.
 410  *
 411  * \param f struct to initialize.
 412  */
 413 void fecdec_filter_init(struct filter *f)
 414 {
 415         f->convert = fecdec;
 416         f->close = fecdec_close;
 417         f->open = fecdec_open;
 418 }