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 (128 * 1024)
  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 };
  50
  51 /**
  52  * The status of one partially received FEC group.
  53  */
  54 struct fecdec_group {
  55         /** The header read from the last slice. */
  56         struct fec_header h;
  57         /** How many slices received so far. */
  58         int num_received_slices;
  59         /** The size of the \a idx and the \a data arrays below. */
  60         int num_slices;
  61         /** Array of indices of the received slices. */
  62         int *idx;
  63         /** Content of the received slices. */
  64         unsigned char **data;
  65 };
  66
  67 /**
  68  * Data private to the fecdec filter.
  69  */
  70 struct private_fecdec_data {
  71         /** Used by the fec core code. */
  72         struct fec_parms *fec;
  73         /** Keeps track of what was received so far. */
  74         struct fecdec_group groups[NUM_FEC_GROUPS];
  75 };
  76
  77 /** Iterate over all fecdec groups. */
  78 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
  79         (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
  80
  81 static int group_complete(struct fecdec_group *fg)
  82 {
  83         return fg->num_received_slices >= fg->h.data_slices_per_group;
  84 }
  85
  86 static int group_empty(struct fecdec_group *fg)
  87 {
  88         return fg->num_received_slices == 0;
  89 }
  90
  91 static void clear_group(struct fecdec_group *fg)
  92 {
  93         int i;
  94
  95         for (i = 0; i < fg->num_slices; i++) {
  96                 free(fg->data[i]);
  97                 fg->data[i] = NULL;
  98                 fg->idx[i] = -1;
  99         }
 100         free(fg->data);
 101         free(fg->idx);
 102         fg->num_slices = 0;
 103         memset(&fg->h, 0, sizeof(struct fec_header));
 104         fg->num_received_slices = 0;
 105 }
 106
 107 static int find_group(struct fec_header *h,
 108                 struct private_fecdec_data *pfd, struct fecdec_group **result)
 109 {
 110         struct fecdec_group *fg;
 111
 112         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 113                 if (fg->h.group_num != h->group_num)
 114                         continue;
 115                 if (fg->h.slices_per_group != h->slices_per_group)
 116                         continue;
 117                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 118                         continue;
 119                 *result = fg;
 120                 return 1;
 121         }
 122         return 0;
 123 }
 124
 125 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 126 {
 127         struct fecdec_group *fg;
 128
 129         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 130                 if (fg->num_received_slices == 0)
 131                         return fg;
 132         }
 133         return NULL;
 134 }
 135
 136 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 137 {
 138         struct fecdec_group *fg;
 139
 140         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 141                 if (!group_complete(fg))
 142                         continue;
 143                 clear_group(fg);
 144                 return fg;
 145         }
 146         return NULL;
 147 }
 148
 149 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 150 {
 151         struct fecdec_group *fg, *oldest = NULL;
 152
 153         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 154                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 155                         oldest = fg;
 156         }
 157         if (!group_complete(oldest) && !group_empty(oldest))
 158                 PARA_WARNING_LOG("Clearing incomplete group %d "
 159                         "(contains %d slices)\n", fg->h.group_num,
 160                         fg->num_received_slices);
 161         clear_group(oldest);
 162         return oldest;
 163 }
 164
 165 /* returns 1 if the group was found, 0 if not, negative on errors */
 166 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 167                 struct fecdec_group **result)
 168 {
 169         struct fecdec_group *fg;
 170         int ret = find_group(h, pfd, &fg);
 171
 172         if (ret < 0)
 173                 return ret;
 174         if (ret > 0) /* found group */
 175                 goto success;
 176         /* group not found */
 177         fg = find_unused_group(pfd);
 178         if (fg)
 179                 goto success;
 180         fg = try_to_free_group(pfd);
 181         if (fg)
 182                 goto success;
 183         fg = free_oldest_group(pfd);
 184         ret = 0;
 185 success:
 186         fg->h = *h;
 187         *result = fg;
 188         return ret;
 189 }
 190
 191 /*
 192  * returns 1 if slice was added, zero otherwise (because the group was already
 193  * complete). In any case the number of received slices is being increased by
 194  * one.
 195  */
 196 static int add_slice(char *buf, struct fecdec_group *fg)
 197 {
 198         int r, slice_num;
 199
 200         if (group_complete(fg)) {
 201                 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
 202                         fg->h.slice_num);
 203                 fg->num_received_slices++;
 204                 return 0;
 205         }
 206         slice_num = fg->h.slice_num;
 207         if (fg->num_slices == 0) {
 208                 fg->num_slices = fg->h.slices_per_group;
 209                 fg->idx = malloc(fg->num_slices * sizeof(int));
 210                 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
 211                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 212         }
 213         r = fg->num_received_slices;
 214         fg->idx[r] = slice_num;
 215         fg->data[r] = malloc(fg->h.slice_bytes);
 216         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 217         fg->num_received_slices++;
 218         return 1;
 219 }
 220
 221 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 222 {
 223         int i, ret, sb = fg->h.slice_bytes;
 224         size_t written = 0;
 225         struct private_fecdec_data *pfd = fn->private_data;
 226
 227         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 228         if (ret < 0)
 229                 return ret;
 230         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 231                 fg->h.group_num, fg->h.group_bytes,
 232                 fg->h.data_slices_per_group * sb);
 233         for (i = 0; i < fg->h.data_slices_per_group; i++) {
 234                 size_t n = sb;
 235                 if (n + written > fg->h.group_bytes)
 236                         n = fg->h.group_bytes - written;
 237                 if (fn->loaded + n > fn->bufsize)
 238                         return -E_FECDEC_OVERRUN;
 239                 memcpy(fn->buf + fn->loaded, fg->data[i], n);
 240                 fn->loaded += n;
 241                 written += n;
 242         }
 243         return 0;
 244 }
 245
 246 /**
 247  * Read a fec header from a buffer.
 248  *
 249  * \param buf The buffer to write to.
 250  * \param h The fec header to write.
 251  */
 252 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 253 {
 254         uint32_t magic;
 255
 256         if (len < FEC_HEADER_SIZE)
 257                 return 0;
 258         magic = read_u32(buf);
 259         if (magic != FEC_MAGIC)
 260                 return -E_BAD_FEC_HEADER;
 261         h->slices_per_group = read_u8(buf + 4);
 262         h->data_slices_per_group = read_u8(buf + 5);
 263         h->audio_header_size = read_u32(buf + 6);
 264
 265         h->group_num = read_u32(buf + 10);
 266         h->group_bytes = read_u32(buf + 14);
 267
 268         h->slice_num = read_u8(buf + 18);
 269         h->slice_bytes = read_u16(buf + 20);
 270         if (!h->group_bytes && & h->slice_bytes)
 271                 return -E_FECDEC_EOF;
 272 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 273 //              h->group_num, h->slice_num, h->slices_per_group);
 274         return 1;
 275 }
 276
 277 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 278 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 279                 struct filter_node *fn)
 280 {
 281         struct fecdec_group *fg;
 282         int ret;
 283         struct private_fecdec_data *pfd = fn->private_data;
 284
 285         if (h->slice_bytes > len) /* can not use the thing, try to read more */
 286                 return 0;
 287         ret = get_group(h, pfd, &fg);
 288         if (ret < 0)
 289                 return ret;
 290         if (!add_slice(buf, fg))
 291                 return 1;
 292         if (group_complete(fg)) {
 293                 if (!pfd->fec) {
 294                         int k = h->data_slices_per_group, n = h->slices_per_group;
 295                         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 296                         ret = fec_new(k, n, &pfd->fec);
 297                         if (ret < 0)
 298                                 return ret;
 299                 }
 300                 ret = decode_group(fg, fn);
 301                 if (ret < 0)
 302                         return ret;
 303         }
 304         return 1;
 305 }
 306
 307 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
 308 {
 309         int ret;
 310         struct fec_header h;
 311
 312         ret = read_fec_header(buf, len, &h);
 313         if (ret <= 0)
 314                 return ret;
 315         if (h.slice_bytes > fn->bufsize)
 316                 return -E_BAD_SLICE_SIZE;
 317         if (h.slice_num > h.slices_per_group)
 318                 return -E_BAD_SLICE_NUM;
 319         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 320                 &h, fn);
 321         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 322         if (ret <= 0)
 323                 return ret;
 324         return FEC_HEADER_SIZE + h.slice_bytes;
 325 }
 326
 327 static void fecdec_close(struct filter_node *fn)
 328 {
 329         struct private_fecdec_data *pfd = fn->private_data;
 330         struct fecdec_group *fg;
 331
 332         FOR_EACH_FECDEC_GROUP(fg, pfd)
 333                 clear_group(fg);
 334         free(fn->buf);
 335         fn->buf = NULL;
 336         free(fn->private_data);
 337         fn->private_data = NULL;
 338 }
 339
 340 static void fecdec_open(struct filter_node *fn)
 341 {
 342         fn->bufsize = FECDEC_OUTBUF_SIZE;
 343         fn->buf = para_malloc(fn->bufsize);
 344         fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
 345         fn->loaded = 0;
 346 }
 347
 348 /**
 349  * The init function of the fecdec filter.
 350  *
 351  * \param f struct to initialize.
 352  */
 353 void fecdec_filter_init(struct filter *f)
 354 {
 355         f->convert = fecdec;
 356         f->close = fecdec_close;
 357         f->open = fecdec_open;
 358 }