+ char *buf = (char *)fc->enc_buf;
+ struct fec_group *g = &fc->group;
+ struct fec_client_parms *p = fc->fcp;
+
+ write_u32(buf, FEC_MAGIC);
+
+ write_u8(buf + 4, p->slices_per_group + fc->num_extra_slices);
+ write_u8(buf + 5, p->data_slices_per_group + fc->num_extra_slices);
+ write_u32(buf + 6, g->num_header_slices? vsst->header_len : 0);
+
+ write_u32(buf + 10, g->num);
+ write_u32(buf + 14, g->bytes);
+
+ write_u8(buf + 18, fc->current_slice_num);
+ write_u16(buf + 20, p->max_slice_bytes - FEC_HEADER_SIZE);
+ write_u8(buf + 22, g->first_chunk? 0 : 1);
+ write_u8(buf + 23, vsst->header_len? 1 : 0);
+ memset(buf + 24, 0, 7);
+}
+
+static int need_audio_header(struct fec_client *fc, struct vss_task *vsst)
+{
+ if (!mmd->current_chunk) {
+ tv_add(now, &vsst->header_interval, &fc->next_header_time);
+ return 0;
+ }
+ if (!vsst->header_buf)
+ return 0;
+ if (!vsst->header_len)
+ return 0;
+ if (fc->group.num && tv_diff(&fc->next_header_time, now, NULL) < 0)
+ return 0;
+ tv_add(now, &vsst->header_interval, &fc->next_header_time);
+ return 1;
+}
+
+static uint8_t num_slices(long unsigned bytes, struct fec_client *fc)
+{
+ uint16_t m = fc->fcp->max_slice_bytes - FEC_HEADER_SIZE;
+ return (bytes + m - 1) / m;
+}
+
+static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
+{
+ int i, k, data_slices;
+ size_t len;
+ const char *buf, *start_buf;
+ struct timeval tmp, *chunk_tv = vss_chunk_time();
+ struct fec_group *g = &fc->group;
+ unsigned slice_bytes = fc->fcp->max_slice_bytes - FEC_HEADER_SIZE;
+ uint32_t max_data_size;
+
+ assert(chunk_tv);
+ k = fc->fcp->data_slices_per_group + fc->num_extra_slices;
+ if (fc->first_stream_chunk < 0) {
+ uint32_t largest = afh_get_largest_chunk_size(&mmd->afd.afhi)
+ + vsst->header_len;
+ uint8_t needed = num_slices(largest, fc), want;
+ if (needed > fc->fcp->data_slices_per_group)
+ PARA_WARNING_LOG("fec parms insufficient for this audio file\n");
+ want = PARA_MAX(needed, fc->fcp->data_slices_per_group);
+ if (want != k) {
+ int ret;
+ fec_free(fc->parms);
+ fc->src_data = para_realloc(fc->src_data, want * sizeof(char *));
+ ret = fec_new(want, want + fc->fcp->slices_per_group
+ - fc->fcp->data_slices_per_group, &fc->parms);
+ if (ret < 0)
+ return ret;
+ k = want;
+ fc->num_extra_slices = 0;
+ if (k > fc->fcp->data_slices_per_group) {
+ fc->num_extra_slices = k - fc->fcp->data_slices_per_group;
+ PARA_NOTICE_LOG("using %d extra slices\n",
+ fc->num_extra_slices);
+ }
+ }
+ fc->stream_start = *now;
+ fc->first_stream_chunk = mmd->current_chunk;
+ g->first_chunk = mmd->current_chunk;
+ g->num = 0;
+ } else {
+ g->first_chunk += g->num_chunks;
+ g->num++;
+ }
+ if (g->first_chunk >= mmd->afd.afhi.chunks_total)
+ return 0;
+ if (need_audio_header(fc, vsst))
+ g->num_header_slices = num_slices(vsst->header_len, fc);
+ else
+ g->num_header_slices = 0;
+ afh_get_chunk(g->first_chunk, &mmd->afd.afhi, vsst->map, &start_buf,
+ &len);
+ data_slices = k - g->num_header_slices;
+ assert(data_slices);
+ max_data_size = slice_bytes * data_slices;
+ g->bytes = 0;
+ for (i = g->first_chunk; i < mmd->afd.afhi.chunks_total; i++) {
+ afh_get_chunk(i, &mmd->afd.afhi, vsst->map, &buf, &len);
+ if (g->bytes + len > max_data_size)
+ break;
+ g->bytes += len;
+ }
+ g->num_chunks = i - g->first_chunk;
+ assert(g->num_chunks);
+ fc->current_slice_num = 0;
+
+ /* setup header slices */
+ buf = vsst->header_buf;
+ for (i = 0; i < g->num_header_slices; i++) {
+ fc->src_data[i] = (const unsigned char *)buf;
+ buf += slice_bytes;
+ }
+
+ /* setup data slices */
+ buf = start_buf;
+ for (i = g->num_header_slices; i < k; i++) {
+ if (buf + slice_bytes > vsst->map + mmd->size)
+ /*
+ * Can not use the memory mapped audio file for this
+ * slice as it goes beyond the map. This slice will not
+ * be fully used.
+ */
+ break;
+ fc->src_data[i] = (const unsigned char *)buf;
+ buf += slice_bytes;
+ }
+ if (i < k) {
+ uint32_t payload_size = vsst->map + mmd->size - buf;
+ memcpy(fc->extra_src_buf, buf, payload_size);
+ fc->src_data[i] = fc->extra_src_buf;
+ i++;
+ /* use arbitrary data for all remaining slices */
+ buf = vsst->map;
+ for (; i < k; i++)
+ fc->src_data[i] = (const unsigned char *)buf;
+ }
+
+ /* setup group timing */
+ tv_scale(g->first_chunk - fc->first_stream_chunk, chunk_tv, &tmp);
+ tv_add(&fc->stream_start, &tmp, &g->start);
+ if (g->num) /* quick hack to avoid buffer underruns */
+ g->start.tv_sec--;
+ tv_scale(g->num_chunks, chunk_tv, &tmp); /* group duration */
+ tv_divide(fc->fcp->slices_per_group + fc->num_extra_slices,
+ &tmp, &g->slice_duration);
+
+ PARA_DEBUG_LOG("FEC group %d: %d chunks (%d - %d), %d header slices, %d data slices\n",
+ g->num, g->num_chunks, g->first_chunk,
+ g->first_chunk + g->num_chunks - 1,
+ g->num_header_slices, data_slices
+ );
+ PARA_DEBUG_LOG("durations (group/chunk/slice): %lu/%lu/%lu\n",
+ tv2ms(&tmp), tv2ms(chunk_tv), tv2ms(&g->slice_duration));
+ return 1;
+}
+
+static int compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst)
+{
+ if (fc->first_stream_chunk < 0 || fc->current_slice_num
+ == fc->fcp->slices_per_group + fc->num_extra_slices) {
+ if (!setup_next_fec_group(fc, vsst))
+ return 0;
+ }
+ write_fec_header(fc, vsst);
+ fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE,
+ fc->current_slice_num,
+ fc->fcp->max_slice_bytes - FEC_HEADER_SIZE);
+ return 1;