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 (16 * 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->h.slices_per_group != h->slices_per_group)
 123                         continue;
 124                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 125                         continue;
 126                 *result = fg;
 127                 return 1;
 128         }
 129         return 0;
 130 }
 131
 132 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 133 {
 134         struct fecdec_group *fg;
 135
 136         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 137                 if (fg->num_received_slices == 0)
 138                         return fg;
 139         }
 140         return NULL;
 141 }
 142
 143 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 144 {
 145         struct fecdec_group *fg;
 146
 147         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 148                 if (!group_complete(fg))
 149                         continue;
 150                 clear_group(fg);
 151                 return fg;
 152         }
 153         return NULL;
 154 }
 155
 156 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 157 {
 158         struct fecdec_group *fg, *oldest = NULL;
 159
 160         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 161                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 162                         oldest = fg;
 163         }
 164         if (!group_complete(oldest) && !group_empty(oldest))
 165                 PARA_WARNING_LOG("Clearing incomplete group %d "
 166                         "(contains %d slices)\n", fg->h.group_num,
 167                         fg->num_received_slices);
 168         clear_group(oldest);
 169         return oldest;
 170 }
 171
 172 /* returns 1 if the group was found, 0 if not, negative on errors */
 173 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 174                 struct fecdec_group **result)
 175 {
 176         struct fecdec_group *fg;
 177         int ret = find_group(h, pfd, &fg);
 178
 179         if (ret < 0)
 180                 return ret;
 181         if (ret > 0) /* found group */
 182                 goto success;
 183         /* group not found */
 184         fg = find_unused_group(pfd);
 185         if (fg)
 186                 goto success;
 187         fg = try_to_free_group(pfd);
 188         if (fg)
 189                 goto success;
 190         fg = free_oldest_group(pfd);
 191         ret = 0;
 192 success:
 193         fg->h = *h;
 194         *result = fg;
 195         return ret;
 196 }
 197
 198 /*
 199  * returns 1 if slice was added, zero otherwise (because the group was already
 200  * complete). In any case the number of received slices is being increased by
 201  * one.
 202  */
 203 static int add_slice(char *buf, struct fecdec_group *fg)
 204 {
 205         int r, slice_num;
 206
 207         if (group_complete(fg)) {
 208                 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
 209                         fg->h.slice_num);
 210                 fg->num_received_slices++;
 211                 return 0;
 212         }
 213         slice_num = fg->h.slice_num;
 214         if (fg->num_slices == 0) {
 215                 fg->num_slices = fg->h.slices_per_group;
 216                 fg->idx = malloc(fg->num_slices * sizeof(int));
 217                 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
 218                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 219         }
 220         r = fg->num_received_slices;
 221         fg->idx[r] = slice_num;
 222         fg->data[r] = malloc(fg->h.slice_bytes);
 223         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 224         fg->num_received_slices++;
 225         return 1;
 226 }
 227
 228 enum fec_group_usability {
 229         FEC_GROUP_UNUSABLE,
 230         FEC_GROUP_USABLE,
 231         FEC_GROUP_USABLE_SKIP_HEADER,
 232 };
 233
 234 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 235                 struct private_fecdec_data *pfd)
 236 {
 237         struct fec_header *h = &fg->h;
 238
 239         if (!h->header_stream)
 240                 return FEC_GROUP_USABLE;
 241         if (pfd->have_header) {
 242                 if (h->audio_header_size)
 243                         return FEC_GROUP_USABLE_SKIP_HEADER;
 244                 return FEC_GROUP_USABLE;
 245         }
 246         if (fg->h.bos)
 247                 return FEC_GROUP_USABLE;
 248         if (fg->h.audio_header_size)
 249                 return FEC_GROUP_USABLE;
 250         return FEC_GROUP_UNUSABLE;
 251 }
 252
 253 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 254 {
 255         int i, ret, sb = fg->h.slice_bytes;
 256         size_t written = 0, need;
 257         struct private_fecdec_data *pfd = fn->private_data;
 258         enum fec_group_usability u = group_is_usable(fg, pfd);
 259
 260         if (u == FEC_GROUP_UNUSABLE) {
 261                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 262                 return 0;
 263         }
 264         PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
 265                 fg->h.data_slices_per_group);
 266         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 267         if (ret < 0)
 268                 return ret;
 269         pfd->have_header = 1;
 270         i = 0;
 271         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 272                 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
 273                         / fg->h.slice_bytes;
 274                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 275         }
 276         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 277                 fg->h.group_num, fg->h.group_bytes,
 278                 fg->h.data_slices_per_group * sb);
 279         need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
 280         if (need > fn->bufsize) {
 281                 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
 282                 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
 283                         return -E_FECDEC_OVERRUN;
 284                 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
 285                 fn->buf = para_realloc(fn->buf, fn->bufsize);
 286         }
 287         for (; i < fg->h.data_slices_per_group; i++) {
 288                 size_t n = sb;
 289                 if (n + written > fg->h.group_bytes)
 290                         n = fg->h.group_bytes - written;
 291                 memcpy(fn->buf + fn->loaded, fg->data[i], n);
 292                 fn->loaded += n;
 293                 written += n;
 294         }
 295         return 0;
 296 }
 297
 298 /**
 299  * Read a fec header from a buffer.
 300  *
 301  * \param buf The buffer to write to.
 302  * \param h The fec header to write.
 303  */
 304 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 305 {
 306         uint32_t magic;
 307
 308         if (len < FEC_HEADER_SIZE)
 309                 return 0;
 310         magic = read_u32(buf);
 311         if (magic != FEC_MAGIC)
 312                 return -E_BAD_FEC_HEADER;
 313         h->slices_per_group = read_u8(buf + 4);
 314         h->data_slices_per_group = read_u8(buf + 5);
 315         h->audio_header_size = read_u32(buf + 6);
 316
 317         h->group_num = read_u32(buf + 10);
 318         h->group_bytes = read_u32(buf + 14);
 319
 320         h->slice_num = read_u8(buf + 18);
 321         h->slice_bytes = read_u16(buf + 20);
 322         h->bos = read_u8(buf + 22);
 323         h->header_stream = read_u8(buf + 23);
 324         if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 325                 return -E_FECDEC_EOF;
 326 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 327 //              h->group_num, h->slice_num, h->slices_per_group);
 328         return 1;
 329 }
 330
 331 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 332 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 333                 struct filter_node *fn)
 334 {
 335         struct fecdec_group *fg;
 336         int ret;
 337         struct private_fecdec_data *pfd = fn->private_data;
 338
 339         if (h->slice_bytes > len) /* can not use the thing, try to read more */
 340                 return 0;
 341         ret = get_group(h, pfd, &fg);
 342         if (ret < 0)
 343                 return ret;
 344         if (!add_slice(buf, fg))
 345                 return 1;
 346         if (group_complete(fg)) {
 347                 if (!pfd->fec) {
 348                         int k = h->data_slices_per_group, n = h->slices_per_group;
 349                         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 350                         ret = fec_new(k, n, &pfd->fec);
 351                         if (ret < 0)
 352                                 return ret;
 353                 }
 354                 ret = decode_group(fg, fn);
 355                 if (ret < 0)
 356                         return ret;
 357         }
 358         return 1;
 359 }
 360
 361 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
 362 {
 363         int ret;
 364         struct fec_header h;
 365
 366         ret = read_fec_header(buf, len, &h);
 367         if (ret <= 0)
 368                 return ret;
 369         if (!h.slice_bytes || h.slice_bytes > fn->bufsize)
 370                 return -E_BAD_SLICE_SIZE;
 371         if (h.slice_num > h.slices_per_group)
 372                 return -E_BAD_SLICE_NUM;
 373         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 374                 &h, fn);
 375         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 376         if (ret <= 0)
 377                 return ret;
 378         return FEC_HEADER_SIZE + h.slice_bytes;
 379 }
 380
 381 static void fecdec_close(struct filter_node *fn)
 382 {
 383         struct private_fecdec_data *pfd = fn->private_data;
 384         struct fecdec_group *fg;
 385
 386         FOR_EACH_FECDEC_GROUP(fg, pfd)
 387                 clear_group(fg);
 388         free(fn->buf);
 389         fn->buf = NULL;
 390         fec_free(pfd->fec);
 391         free(fn->private_data);
 392         fn->private_data = NULL;
 393 }
 394
 395 static void fecdec_open(struct filter_node *fn)
 396 {
 397         fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
 398         fn->buf = para_malloc(fn->bufsize);
 399         fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
 400         fn->loaded = 0;
 401 }
 402
 403 /**
 404  * The init function of the fecdec filter.
 405  *
 406  * \param f struct to initialize.
 407  */
 408 void fecdec_filter_init(struct filter *f)
 409 {
 410         f->convert = fecdec;
 411         f->close = fecdec_close;
 412         f->open = fecdec_open;
 413 }