+static int num_slices(long unsigned bytes, int max_payload, int rs)
+{
+ int ret;
+
+ assert(max_payload > 0);
+ assert(rs > 0);
+ ret = DIV_ROUND_UP(bytes, max_payload);
+ if (ret + rs > 255)
+ return -E_BAD_CT;
+ return ret;
+}
+
+/* set group start and group duration */
+static void set_group_timing(struct fec_client *fc, struct fec_group *g)
+{
+ struct timeval *chunk_tv = vss_chunk_time();
+
+ tv_scale(g->num_chunks, chunk_tv, &g->duration);
+ tv_divide(fc->fcp->slices_per_group + fc->num_extra_slices,
+ &g->duration, &g->slice_duration);
+ PARA_DEBUG_LOG("durations (group/chunk/slice): %lu/%lu/%lu\n",
+ tv2ms(&g->duration), tv2ms(chunk_tv), tv2ms(&g->slice_duration));
+}
+
+static int initialize_fec_client(struct fec_client *fc, struct vss_task *vsst)
+{
+ int k, n, ret;
+ int hs, ds, rs; /* header/data/redundant slices */
+ struct fec_client_parms *fcp = fc->fcp;
+
+ /* set mps */
+ if (fcp->init_fec) {
+ /*
+ * Set the maximum slice size to the Maximum Packet Size if the
+ * transport protocol allows to determine this value. The user
+ * can specify a slice size up to this value.
+ */
+ ret = fcp->init_fec(fc->sc);
+ if (ret < 0)
+ return ret;
+ fc->mps = ret;
+ } else
+ fc->mps = generic_max_transport_msg_size(fc->sc->fd);
+ if (fc->mps <= FEC_HEADER_SIZE)
+ return -ERRNO_TO_PARA_ERROR(EINVAL);
+
+ rs = fc->fcp->slices_per_group - fc->fcp->data_slices_per_group;
+ ret = num_slices(vsst->header_len, fc->mps - FEC_HEADER_SIZE, rs);
+ if (ret < 0)
+ return ret;
+ hs = ret;
+ ret = num_slices(mmd->afd.max_chunk_size, fc->mps - FEC_HEADER_SIZE, rs);
+ if (ret < 0)
+ return ret;
+ ds = ret;
+ k = hs + ds;
+ if (k < fc->fcp->data_slices_per_group)
+ k = fc->fcp->data_slices_per_group;
+ fc->num_extra_slices = k - fc->fcp->data_slices_per_group;
+ n = k + rs;
+ fec_free(fc->parms);
+ ret = fec_new(k, n, &fc->parms);
+ if (ret < 0)
+ return ret;
+ PARA_INFO_LOG("mps: %d, k: %d, n: %d, extra slices: %d\n",
+ fc->mps, k, n, fc->num_extra_slices);
+ fc->src_data = para_realloc(fc->src_data, k * sizeof(char *));
+ fc->enc_buf = para_realloc(fc->enc_buf, fc->mps);
+ fc->extra_src_buf = para_realloc(fc->extra_src_buf, fc->mps);
+
+ fc->state = FEC_STATE_READY_TO_RUN;
+ fc->next_header_time.tv_sec = 0;
+ fc->stream_start = *now;
+ fc->first_stream_chunk = mmd->current_chunk;
+ return 1;
+}
+
+static void compute_group_size(struct vss_task *vsst, struct fec_group *g,
+ int max_bytes)
+{
+ int i, max_chunks = PARA_MAX(1LU, 150 / tv2ms(vss_chunk_time()));
+
+ g->num_chunks = 0;
+ g->bytes = 0;
+ /*
+ * Include chunks into the group until the group duration is at least
+ * 150ms. For ogg and wma, a single chunk's duration (ogg page/wma
+ * super frame) is already larger than 150ms, so a FEC group consists
+ * of exactly one chunk for these audio formats.
+ */
+ for (i = 0;; i++) {