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 <regex.h>
  10
  11 #include <dirent.h>
  12 #include "para.h"
  13 #include "error.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "ggo.h"
  17 #include "filter.h"
  18 #include "string.h"
  19 #include "portable_io.h"
  20 #include "fec.h"
  21 #include "fd.h"
  22
  23 /**
  24  * How many FEC groups to store in memory.
  25  *
  26  * Packet reordering requires to keep more than one FEC group in memory because
  27  * slices belonging to the next FEC group may arrive before the current FEC group
  28  * is complete.
  29  */
  30 #define NUM_FEC_GROUPS 3
  31
  32 /** Default size of the output buffer of the fecdec filter. */
  33 #define FECDEC_DEFAULT_OUTBUF_SIZE (3 * 1024)
  34 /** Maximal size of the output buffer of the fecdec filter. */
  35 #define FECDEC_MAX_OUTBUF_SIZE (1024 * 1024)
  36
  37 /** Data read from the header of a slice. */
  38 struct fec_header {
  39         /** Total number of slices in this group. */
  40         uint8_t slices_per_group;
  41         /** Number of slices needed to start decoding. */
  42         uint8_t data_slices_per_group;
  43         /** Size of the ogg vorbis header (zero for mp3, aac). */
  44         uint32_t audio_header_size;
  45         /** Number of the FEC group this slice belongs to. */
  46         uint32_t group_num;
  47         /** Size of the data in this FEC group. */
  48         uint32_t group_bytes;
  49         /** Number of this slice in the group. */
  50         uint8_t slice_num;
  51         /** Used data bytes of this slice. */
  52         uint16_t slice_bytes;
  53         /** Non-zero if this group is the beginning of the stream. */
  54         uint8_t bos;
  55         /** Non-zero if this stream embedds audio headers into fec groups. */
  56         uint8_t header_stream;
  57 };
  58
  59 /**
  60  * The status of one partially received FEC group.
  61  */
  62 struct fecdec_group {
  63         /** The header read from the last slice. */
  64         struct fec_header h;
  65         /** How many slices received so far. */
  66         int num_received_slices;
  67         /** The size of the \a idx and the \a data arrays below. */
  68         int num_slices;
  69         /** Array of indices of the received slices. */
  70         int *idx;
  71         /** Content of the received slices. */
  72         unsigned char **data;
  73 };
  74
  75 /**
  76  * Data private to the fecdec filter.
  77  */
  78 struct private_fecdec_data {
  79         /** Used by the fec core code. */
  80         struct fec_parms *fec;
  81         /** Keeps track of what was received so far. */
  82         struct fecdec_group groups[NUM_FEC_GROUPS];
  83         /** Whether an audio file header was already received. */
  84         int have_header;
  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         free(fg->idx);
 112         fg->num_slices = 0;
 113         memset(&fg->h, 0, sizeof(struct fec_header));
 114         fg->num_received_slices = 0;
 115 }
 116
 117 static int find_group(struct fec_header *h,
 118                 struct private_fecdec_data *pfd, struct fecdec_group **result)
 119 {
 120         struct fecdec_group *fg;
 121
 122         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 123                 if (fg->h.group_num != h->group_num)
 124                         continue;
 125                 if (fg->num_received_slices == 0)
 126                         goto success;
 127                 if (fg->h.slices_per_group != h->slices_per_group)
 128                         return -E_BAD_FEC_HEADER;
 129                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 130                         return -E_BAD_FEC_HEADER;
 131                 if (fg->h.group_bytes != h->group_bytes)
 132                         return -E_BAD_FEC_HEADER;
 133 success:
 134                 *result = fg;
 135                 return 1;
 136         }
 137         return 0;
 138 }
 139
 140 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 141 {
 142         struct fecdec_group *fg;
 143
 144         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 145                 if (fg->num_received_slices == 0)
 146                         return fg;
 147         }
 148         return NULL;
 149 }
 150
 151 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 152 {
 153         struct fecdec_group *fg;
 154
 155         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 156                 if (!group_complete(fg))
 157                         continue;
 158                 clear_group(fg);
 159                 return fg;
 160         }
 161         return NULL;
 162 }
 163
 164 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 165 {
 166         struct fecdec_group *fg, *oldest = NULL;
 167
 168         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 169                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 170                         oldest = fg;
 171         }
 172         if (!group_complete(oldest) && !group_empty(oldest))
 173                 PARA_WARNING_LOG("Clearing incomplete group %d "
 174                         "(contains %d slices)\n", oldest->h.group_num,
 175                         oldest->num_received_slices);
 176         clear_group(oldest);
 177         return oldest;
 178 }
 179
 180 /* returns 1 if the group was found, 0 if not, negative on errors */
 181 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 182                 struct fecdec_group **result)
 183 {
 184         struct fecdec_group *fg;
 185         int ret = find_group(h, pfd, &fg);
 186
 187         if (ret < 0)
 188                 return ret;
 189         if (ret > 0) /* found group */
 190                 goto success;
 191         /* group not found */
 192         fg = find_unused_group(pfd);
 193         if (fg)
 194                 goto success;
 195         fg = try_to_free_group(pfd);
 196         if (fg)
 197                 goto success;
 198         fg = free_oldest_group(pfd);
 199         ret = 0;
 200 success:
 201         fg->h = *h;
 202         *result = fg;
 203         return ret;
 204 }
 205
 206 /*
 207  * returns 1 if slice was added, zero otherwise (because the group was already
 208  * complete). In any case the number of received slices is being increased by
 209  * one.
 210  */
 211 static int add_slice(char *buf, struct fecdec_group *fg)
 212 {
 213         int r, slice_num;
 214
 215         if (group_complete(fg)) {
 216                 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
 217                         fg->h.slice_num);
 218                 fg->num_received_slices++;
 219                 return 0;
 220         }
 221         slice_num = fg->h.slice_num;
 222         if (fg->num_slices == 0) {
 223                 fg->num_slices = fg->h.slices_per_group;
 224                 fg->idx = malloc(fg->num_slices * sizeof(int));
 225                 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
 226                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 227         }
 228         r = fg->num_received_slices;
 229         fg->idx[r] = slice_num;
 230         fg->data[r] = malloc(fg->h.slice_bytes);
 231         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 232         fg->num_received_slices++;
 233         return 1;
 234 }
 235
 236 enum fec_group_usability {
 237         FEC_GROUP_UNUSABLE,
 238         FEC_GROUP_USABLE,
 239         FEC_GROUP_USABLE_SKIP_HEADER,
 240 };
 241
 242 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 243                 struct private_fecdec_data *pfd)
 244 {
 245         struct fec_header *h = &fg->h;
 246
 247         if (!h->header_stream)
 248                 return FEC_GROUP_USABLE;
 249         if (pfd->have_header) {
 250                 if (h->audio_header_size)
 251                         return FEC_GROUP_USABLE_SKIP_HEADER;
 252                 return FEC_GROUP_USABLE;
 253         }
 254         if (fg->h.bos)
 255                 return FEC_GROUP_USABLE;
 256         if (fg->h.audio_header_size)
 257                 return FEC_GROUP_USABLE;
 258         return FEC_GROUP_UNUSABLE;
 259 }
 260
 261 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 262 {
 263         int i, ret, sb = fg->h.slice_bytes;
 264         size_t written = 0, need;
 265         struct private_fecdec_data *pfd = fn->private_data;
 266         enum fec_group_usability u = group_is_usable(fg, pfd);
 267
 268         if (u == FEC_GROUP_UNUSABLE) {
 269                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 270                 return 0;
 271         }
 272         PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
 273                 fg->h.data_slices_per_group);
 274         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 275         if (ret < 0)
 276                 return ret;
 277         pfd->have_header = 1;
 278         i = 0;
 279         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 280                 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
 281                         / fg->h.slice_bytes;
 282                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 283         }
 284         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 285                 fg->h.group_num, fg->h.group_bytes,
 286                 fg->h.data_slices_per_group * sb);
 287         need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
 288         if (need > fn->bufsize) {
 289                 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
 290                 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
 291                         return -E_FECDEC_OVERRUN;
 292                 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
 293                 fn->buf = para_realloc(fn->buf, fn->bufsize);
 294         }
 295         for (; i < fg->h.data_slices_per_group; i++) {
 296                 size_t n = sb;
 297                 if (n + written > fg->h.group_bytes)
 298                         n = fg->h.group_bytes - written;
 299                 memcpy(fn->buf + fn->loaded, fg->data[i], n);
 300                 fn->loaded += n;
 301                 written += n;
 302         }
 303         return 0;
 304 }
 305
 306 /**
 307  * Read a fec header from a buffer.
 308  *
 309  * \param buf The buffer to write to.
 310  * \param h The fec header to write.
 311  */
 312 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 313 {
 314         uint32_t magic;
 315
 316         if (len < FEC_HEADER_SIZE)
 317                 return 0;
 318         magic = read_u32(buf);
 319         if (magic != FEC_MAGIC)
 320                 return -E_BAD_FEC_HEADER;
 321         h->slices_per_group = read_u8(buf + 4);
 322         h->data_slices_per_group = read_u8(buf + 5);
 323         h->audio_header_size = read_u32(buf + 6);
 324
 325         h->group_num = read_u32(buf + 10);
 326         h->group_bytes = read_u32(buf + 14);
 327
 328         h->slice_num = read_u8(buf + 18);
 329         h->slice_bytes = read_u16(buf + 20);
 330         h->bos = read_u8(buf + 22);
 331         h->header_stream = read_u8(buf + 23);
 332         if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 333                 return -E_FECDEC_EOF;
 334 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 335 //              h->group_num, h->slice_num, h->slices_per_group);
 336         return 1;
 337 }
 338
 339 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 340 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 341                 struct filter_node *fn)
 342 {
 343         struct fecdec_group *fg;
 344         int ret;
 345         struct private_fecdec_data *pfd = fn->private_data;
 346
 347         if (h->slice_bytes > len) /* can not use the thing, try to read more */
 348                 return 0;
 349         ret = get_group(h, pfd, &fg);
 350         if (ret < 0)
 351                 return ret;
 352         if (!add_slice(buf, fg))
 353                 return 1;
 354         if (group_complete(fg)) {
 355                 if (!pfd->fec) {
 356                         int k = h->data_slices_per_group, n = h->slices_per_group;
 357                         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 358                         ret = fec_new(k, n, &pfd->fec);
 359                         if (ret < 0)
 360                                 return ret;
 361                 }
 362                 ret = decode_group(fg, fn);
 363                 if (ret < 0)
 364                         return ret;
 365         }
 366         return 1;
 367 }
 368
 369 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
 370 {
 371         int ret;
 372         struct fec_header h;
 373
 374         ret = read_fec_header(buf, len, &h);
 375         if (ret <= 0)
 376                 return ret;
 377         if (!h.slice_bytes)
 378                 return -E_BAD_SLICE_SIZE;
 379         if (h.slice_num > h.slices_per_group)
 380                 return -E_BAD_SLICE_NUM;
 381         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 382                 &h, fn);
 383         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 384         if (ret <= 0)
 385                 return ret;
 386         return FEC_HEADER_SIZE + h.slice_bytes;
 387 }
 388
 389 static void fecdec_close(struct filter_node *fn)
 390 {
 391         struct private_fecdec_data *pfd = fn->private_data;
 392         struct fecdec_group *fg;
 393
 394         FOR_EACH_FECDEC_GROUP(fg, pfd)
 395                 clear_group(fg);
 396         free(fn->buf);
 397         fn->buf = NULL;
 398         fec_free(pfd->fec);
 399         free(fn->private_data);
 400         fn->private_data = NULL;
 401 }
 402
 403 static void fecdec_open(struct filter_node *fn)
 404 {
 405         fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
 406         fn->buf = para_malloc(fn->bufsize);
 407         fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
 408         fn->loaded = 0;
 409 }
 410
 411 /**
 412  * The init function of the fecdec filter.
 413  *
 414  * \param f struct to initialize.
 415  */
 416 void fecdec_filter_init(struct filter *f)
 417 {
 418         f->convert = fecdec;
 419         f->close = fecdec_close;
 420         f->open = fecdec_open;
 421 }