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 /** Size of the output buffer of the fecdec filter. */
  31 #define FECDEC_OUTBUF_SIZE (1024 * 1024) /* FIXME: This has to depend on the fec params */
  32
  33 /** Data read from the header of a slice. */
  34 struct fec_header {
  35         /** Total number of slices in this group. */
  36         uint8_t slices_per_group;
  37         /** Number of slices needed to start decoding. */
  38         uint8_t data_slices_per_group;
  39         /** Size of the ogg vorbis header (zero for mp3, aac). */
  40         uint32_t audio_header_size;
  41         /** Number of the FEC group this slice belongs to. */
  42         uint32_t group_num;
  43         /** Size of the data in this FEC group. */
  44         uint32_t group_bytes;
  45         /** Number of this slice in the group. */
  46         uint8_t slice_num;
  47         /** Used data bytes of this slice. */
  48         uint16_t slice_bytes;
  49         /** Non-zero if this group is the beginning of the stream. */
  50         uint8_t bos;
  51         /** Non-zero if this stream embedds audio headers into fec groups. */
  52         uint8_t header_stream;
  53 };
  54
  55 /**
  56  * The status of one partially received FEC group.
  57  */
  58 struct fecdec_group {
  59         /** The header read from the last slice. */
  60         struct fec_header h;
  61         /** How many slices received so far. */
  62         int num_received_slices;
  63         /** The size of the \a idx and the \a data arrays below. */
  64         int num_slices;
  65         /** Array of indices of the received slices. */
  66         int *idx;
  67         /** Content of the received slices. */
  68         unsigned char **data;
  69 };
  70
  71 /**
  72  * Data private to the fecdec filter.
  73  */
  74 struct private_fecdec_data {
  75         /** Used by the fec core code. */
  76         struct fec_parms *fec;
  77         /** Keeps track of what was received so far. */
  78         struct fecdec_group groups[NUM_FEC_GROUPS];
  79         int have_header;
  80 };
  81
  82 /** Iterate over all fecdec groups. */
  83 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
  84         (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
  85
  86 static int group_complete(struct fecdec_group *fg)
  87 {
  88         return fg->num_received_slices >= fg->h.data_slices_per_group;
  89 }
  90
  91 static int group_empty(struct fecdec_group *fg)
  92 {
  93         return fg->num_received_slices == 0;
  94 }
  95
  96 static void clear_group(struct fecdec_group *fg)
  97 {
  98         int i;
  99
 100         for (i = 0; i < fg->num_slices; i++) {
 101                 free(fg->data[i]);
 102                 fg->data[i] = NULL;
 103                 fg->idx[i] = -1;
 104         }
 105         free(fg->data);
 106         free(fg->idx);
 107         fg->num_slices = 0;
 108         memset(&fg->h, 0, sizeof(struct fec_header));
 109         fg->num_received_slices = 0;
 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->h.slices_per_group != h->slices_per_group)
 121                         continue;
 122                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 123                         continue;
 124                 *result = fg;
 125                 return 1;
 126         }
 127         return 0;
 128 }
 129
 130 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 131 {
 132         struct fecdec_group *fg;
 133
 134         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 135                 if (fg->num_received_slices == 0)
 136                         return fg;
 137         }
 138         return NULL;
 139 }
 140
 141 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 142 {
 143         struct fecdec_group *fg;
 144
 145         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 146                 if (!group_complete(fg))
 147                         continue;
 148                 clear_group(fg);
 149                 return fg;
 150         }
 151         return NULL;
 152 }
 153
 154 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 155 {
 156         struct fecdec_group *fg, *oldest = NULL;
 157
 158         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 159                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 160                         oldest = fg;
 161         }
 162         if (!group_complete(oldest) && !group_empty(oldest))
 163                 PARA_WARNING_LOG("Clearing incomplete group %d "
 164                         "(contains %d slices)\n", oldest->h.group_num,
 165                         oldest->num_received_slices);
 166         clear_group(oldest);
 167         return oldest;
 168 }
 169
 170 /* returns 1 if the group was found, 0 if not, negative on errors */
 171 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 172                 struct fecdec_group **result)
 173 {
 174         struct fecdec_group *fg;
 175         int ret = find_group(h, pfd, &fg);
 176
 177         if (ret < 0)
 178                 return ret;
 179         if (ret > 0) /* found group */
 180                 goto success;
 181         /* group not found */
 182         fg = find_unused_group(pfd);
 183         if (fg)
 184                 goto success;
 185         fg = try_to_free_group(pfd);
 186         if (fg)
 187                 goto success;
 188         fg = free_oldest_group(pfd);
 189         ret = 0;
 190 success:
 191         fg->h = *h;
 192         *result = fg;
 193         return ret;
 194 }
 195
 196 /*
 197  * returns 1 if slice was added, zero otherwise (because the group was already
 198  * complete). In any case the number of received slices is being increased by
 199  * one.
 200  */
 201 static int add_slice(char *buf, struct fecdec_group *fg)
 202 {
 203         int r, slice_num;
 204
 205         if (group_complete(fg)) {
 206                 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
 207                         fg->h.slice_num);
 208                 fg->num_received_slices++;
 209                 return 0;
 210         }
 211         slice_num = fg->h.slice_num;
 212         if (fg->num_slices == 0) {
 213                 fg->num_slices = fg->h.slices_per_group;
 214                 fg->idx = malloc(fg->num_slices * sizeof(int));
 215                 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
 216                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 217         }
 218         r = fg->num_received_slices;
 219         fg->idx[r] = slice_num;
 220         fg->data[r] = malloc(fg->h.slice_bytes);
 221         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 222         fg->num_received_slices++;
 223         return 1;
 224 }
 225
 226 enum fec_group_usability {
 227         FEC_GROUP_UNUSABLE,
 228         FEC_GROUP_USABLE,
 229         FEC_GROUP_USABLE_SKIP_HEADER,
 230 };
 231
 232 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 233                 struct private_fecdec_data *pfd)
 234 {
 235         struct fec_header *h = &fg->h;
 236
 237         if (!h->header_stream)
 238                 return FEC_GROUP_USABLE;
 239         if (pfd->have_header) {
 240                 if (h->audio_header_size)
 241                         return FEC_GROUP_USABLE_SKIP_HEADER;
 242                 return FEC_GROUP_USABLE;
 243         }
 244         if (fg->h.bos)
 245                 return FEC_GROUP_USABLE;
 246         if (fg->h.audio_header_size)
 247                 return FEC_GROUP_USABLE;
 248         return FEC_GROUP_UNUSABLE;
 249 }
 250
 251 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 252 {
 253         int i, ret, sb = fg->h.slice_bytes;
 254         size_t written = 0;
 255         struct private_fecdec_data *pfd = fn->private_data;
 256         enum fec_group_usability u = group_is_usable(fg, pfd);
 257
 258         if (u == FEC_GROUP_UNUSABLE) {
 259                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 260                 return 0;
 261         }
 262         PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
 263                 fg->h.data_slices_per_group);
 264         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 265         if (ret < 0)
 266                 return ret;
 267         pfd->have_header = 1;
 268         i = 0;
 269         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 270                 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
 271                         / fg->h.slice_bytes;
 272                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 273         }
 274         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 275                 fg->h.group_num, fg->h.group_bytes,
 276                 fg->h.data_slices_per_group * sb);
 277         for (; i < fg->h.data_slices_per_group; i++) {
 278                 size_t n = sb;
 279                 if (n + written > fg->h.group_bytes)
 280                         n = fg->h.group_bytes - written;
 281                 if (fn->loaded + n > fn->bufsize)
 282                         return -E_FECDEC_OVERRUN;
 283                 memcpy(fn->buf + fn->loaded, fg->data[i], n);
 284                 fn->loaded += n;
 285                 written += n;
 286         }
 287         return 0;
 288 }
 289
 290 /**
 291  * Read a fec header from a buffer.
 292  *
 293  * \param buf The buffer to write to.
 294  * \param h The fec header to write.
 295  */
 296 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 297 {
 298         uint32_t magic;
 299
 300         if (len < FEC_HEADER_SIZE)
 301                 return 0;
 302         magic = read_u32(buf);
 303         if (magic != FEC_MAGIC)
 304                 return -E_BAD_FEC_HEADER;
 305         h->slices_per_group = read_u8(buf + 4);
 306         h->data_slices_per_group = read_u8(buf + 5);
 307         h->audio_header_size = read_u32(buf + 6);
 308
 309         h->group_num = read_u32(buf + 10);
 310         h->group_bytes = read_u32(buf + 14);
 311
 312         h->slice_num = read_u8(buf + 18);
 313         h->slice_bytes = read_u16(buf + 20);
 314         h->bos = read_u8(buf + 22);
 315         h->header_stream = read_u8(buf + 23);
 316         if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 317                 return -E_FECDEC_EOF;
 318 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 319 //              h->group_num, h->slice_num, h->slices_per_group);
 320         return 1;
 321 }
 322
 323 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 324 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 325                 struct filter_node *fn)
 326 {
 327         struct fecdec_group *fg;
 328         int ret;
 329         struct private_fecdec_data *pfd = fn->private_data;
 330
 331         if (h->slice_bytes > len) /* can not use the thing, try to read more */
 332                 return 0;
 333         ret = get_group(h, pfd, &fg);
 334         if (ret < 0)
 335                 return ret;
 336         if (!add_slice(buf, fg))
 337                 return 1;
 338         if (group_complete(fg)) {
 339                 if (!pfd->fec) {
 340                         int k = h->data_slices_per_group, n = h->slices_per_group;
 341                         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 342                         ret = fec_new(k, n, &pfd->fec);
 343                         if (ret < 0)
 344                                 return ret;
 345                 }
 346                 ret = decode_group(fg, fn);
 347                 if (ret < 0)
 348                         return ret;
 349         }
 350         return 1;
 351 }
 352
 353 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
 354 {
 355         int ret;
 356         struct fec_header h;
 357
 358         ret = read_fec_header(buf, len, &h);
 359         if (ret <= 0)
 360                 return ret;
 361         if (!h.slice_bytes || h.slice_bytes > fn->bufsize)
 362                 return -E_BAD_SLICE_SIZE;
 363         if (h.slice_num > h.slices_per_group)
 364                 return -E_BAD_SLICE_NUM;
 365         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 366                 &h, fn);
 367         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 368         if (ret <= 0)
 369                 return ret;
 370         return FEC_HEADER_SIZE + h.slice_bytes;
 371 }
 372
 373 static void fecdec_close(struct filter_node *fn)
 374 {
 375         struct private_fecdec_data *pfd = fn->private_data;
 376         struct fecdec_group *fg;
 377
 378         FOR_EACH_FECDEC_GROUP(fg, pfd)
 379                 clear_group(fg);
 380         free(fn->buf);
 381         fn->buf = NULL;
 382         fec_free(pfd->fec);
 383         free(fn->private_data);
 384         fn->private_data = NULL;
 385 }
 386
 387 static void fecdec_open(struct filter_node *fn)
 388 {
 389         fn->bufsize = FECDEC_OUTBUF_SIZE;
 390         fn->buf = para_malloc(fn->bufsize);
 391         fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
 392         fn->loaded = 0;
 393 }
 394
 395 /**
 396  * The init function of the fecdec filter.
 397  *
 398  * \param f struct to initialize.
 399  */
 400 void fecdec_filter_init(struct filter *f)
 401 {
 402         f->convert = fecdec;
 403         f->close = fecdec_close;
 404         f->open = fecdec_open;
 405 }