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