+ char *buf = (char *)fc->enc_buf;
+
+ write_u32(buf, FEC_MAGIC);
+
+ write_u8(buf + 4, fc->fcp->slices_per_group);
+ write_u8(buf + 5, fc->fcp->data_slices_per_group);
+ write_u32(buf + 6, (uint32_t)0); /* audio header len */
+
+ write_u32(buf + 10, fc->group.num);
+ write_u32(buf + 14, fc->group.bytes);
+
+ write_u8(buf + 18, fc->slice.num);
+ write_u16(buf + 20, fc->slice.bytes);
+ memset(buf + 22, 0, 11);
+}
+
+static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
+{
+ uint32_t max_group_size, last_payload_size;
+ int i, k = fc->fcp->data_slices_per_group;
+ size_t len;
+ const char *start_buf;
+ struct timeval tmp, *chunk_tv = vss_chunk_time();
+
+ assert(chunk_tv);
+ if (fc->first_stream_chunk < 0) {
+ fc->stream_start = *now;
+ fc->first_stream_chunk = mmd->current_chunk;
+ fc->group.first_chunk = mmd->current_chunk;
+ fc->group.num = 0;
+ } else {
+ fc->group.first_chunk += fc->group.num_chunks;
+ fc->group.num++;
+ }
+ if (fc->group.first_chunk >= mmd->afd.afhi.chunks_total)
+ return 0;
+ max_group_size = (fc->fcp->max_slice_bytes - FEC_HEADER_SIZE) * k;
+ afh_get_chunk(fc->group.first_chunk, &mmd->afd.afhi, vsst->map,
+ &start_buf, &len);
+ for (i = fc->group.first_chunk, fc->group.bytes = 0;
+ i < mmd->afd.afhi.chunks_total; i++) {
+ const char *buf;
+
+ afh_get_chunk(i, &mmd->afd.afhi, vsst->map, &buf, &len);
+ if (fc->group.bytes + len > max_group_size)
+ break;
+ fc->group.bytes += len;
+ }
+ fc->group.num_chunks = i - fc->group.first_chunk;
+ fc->slice.num = 0;
+ fc->slice.bytes = ROUND_UP(fc->group.bytes, k) / k;
+
+ /* The last slice will not be fully used */
+ last_payload_size = fc->group.bytes % fc->slice.bytes;
+ if (!last_payload_size)
+ last_payload_size = fc->slice.bytes;
+
+ tv_scale(fc->group.first_chunk - fc->first_stream_chunk, chunk_tv,
+ &tmp);
+ tv_add(&fc->stream_start, &tmp, &fc->group.start);
+ if (fc->group.num) /* quick hack to avoid buffer underruns */
+ fc->group.start.tv_sec--;
+ tv_scale(fc->group.num_chunks, chunk_tv, &fc->group.duration);
+ tv_divide(fc->fcp->slices_per_group, &fc->group.duration,
+ &fc->group.slice_duration);
+
+ for (i = 0; i < k; i++)
+ fc->src_data[i] = (const unsigned char *)start_buf
+ + i * fc->slice.bytes;
+
+ if (start_buf + k * fc->slice.bytes > vsst->map + mmd->size) {
+ /* can not use last slice as it goes beyond the map */
+ if (fc->extra_src_buf_size < fc->slice.bytes) {
+ fc->extra_src_buf = para_realloc(fc->extra_src_buf, fc->slice.bytes);
+ fc->extra_src_buf_size = fc->slice.bytes;
+ }
+ memcpy(fc->extra_src_buf, start_buf + (k - 1) * fc->slice.bytes,
+ last_payload_size);
+ memset(fc->extra_src_buf + last_payload_size, 0,
+ fc->slice.bytes - last_payload_size);
+ fc->src_data[k - 1] = fc->extra_src_buf;
+ }
+ if (fc->enc_buf_size < fc->slice.bytes + FEC_HEADER_SIZE) {
+ fc->enc_buf_size = fc->slice.bytes + FEC_HEADER_SIZE;
+ fc->enc_buf = para_realloc(fc->enc_buf, fc->enc_buf_size);
+ }
+ PARA_INFO_LOG("FEC group %d: %d chunks (%d - %d), duration: %lums\n",
+ fc->group.num, fc->group.num_chunks, fc->group.first_chunk,
+ fc->group.first_chunk + fc->group.num_chunks - 1,
+ tv2ms(&fc->group.duration));
+ return 1;
+}
+
+static int compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst)
+{
+ if (fc->first_stream_chunk < 0 || fc->slice.num
+ == fc->fcp->slices_per_group) {
+ if (!setup_next_fec_group(fc, vsst))
+ return 0;
+ }
+ write_fec_header(fc);
+ fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE,
+ fc->slice.num, fc->slice.bytes);
+ return 1;