X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=vss.c;h=1a038f060bd1f0e2ecfd842e9f08fd7f704f70e2;hp=d205349370f69a9445ff1db7bb1c269b2d6431a7;hb=d96c06ff93493c125b9f4d36655e77d7029ca309;hpb=002731cd3938f3be6b71651e56c062af1adcdec0

diff --git a/vss.c b/vss.c
index d2053493..1a038f06 100644
--- a/vss.c
+++ b/vss.c
@@ -11,18 +11,22 @@
  * senders.
  */
 
+#include <regex.h>
 #include <dirent.h>
+#include <osl.h>
 
 #include "para.h"
 #include "error.h"
+#include "portable_io.h"
+#include "fec.h"
 #include "string.h"
 #include "afh.h"
 #include "afs.h"
 #include "server.h"
 #include "net.h"
 #include "server.cmdline.h"
-#include "vss.h"
 #include "list.h"
+#include "vss.h"
 #include "send.h"
 #include "ipc.h"
 #include "fd.h"
@@ -85,8 +89,434 @@ struct vss_task {
 	const char *header_buf;
 	/** Length of the audio file header. */
 	size_t header_len;
+	/** Time between audio file headers are sent. */
+	struct timeval header_interval;
 };
 
+/**
+ * The list of currently connected fec clients.
+ *
+ * Senders may use \ref vss_add_fec_client() to add entries to the list.
+ */
+static struct list_head fec_client_list;
+
+/**
+ * Data associated with one FEC group.
+ *
+ * A FEC group consists of a fixed number of slices and this number is given by
+ * the \a slices_per_group parameter of struct \ref fec_client_parms. Each FEC
+ * group contains a number of chunks of the current audio file.
+ *
+ * FEC slices directly correspond to the data packages sent by the paraslash
+ * senders that use FEC. Each slice is identified by its group number and its
+ * number within the group. All slices have the same size, but the last slice
+ * of the group may not be filled entirely.
+ */
+struct fec_group {
+	/** The number of the FEC group. */
+	uint32_t num;
+	/** Number of bytes in this group. */
+	uint32_t bytes;
+	/** The first chunk of the current audio file belonging to the group. */
+	uint32_t first_chunk;
+	/** The number of chunks contained in this group. */
+	uint32_t num_chunks;
+	/** When the first chunk was sent. */
+	struct timeval start;
+	/** The duration of the full group. */
+	struct timeval duration;
+	/** The group duration divided by the number of slices. */
+	struct timeval slice_duration;
+	/** Group contains the audio file header that occupies that many slices. */
+	uint8_t num_header_slices;
+};
+
+/**
+ * Describes one connected FEC client.
+ */
+struct fec_client {
+	/** If negative, this client is temporarily disabled. */
+	int error;
+	/** Parameters requested by the client. */
+	struct fec_client_parms *fcp;
+	/** Used by the core FEC code. */
+	struct fec_parms *parms;
+	/** The position of this client in the fec client list. */
+	struct list_head node;
+	/** When the first slice for this client was sent. */
+	struct timeval stream_start;
+	/** The first chunk sent to this FEC client. */
+	int first_stream_chunk;
+	/** Describes the current group. */
+	struct fec_group group;
+	/** The current slice. */
+	uint8_t current_slice_num;
+	/** The data to be FEC-encoded (point to a region within the mapped audio file). */
+	const unsigned char **src_data;
+	/** Last time an audio  header was sent. */
+	struct timeval next_header_time;
+	/** Used for the last source pointer of an audio file. */
+	unsigned char *extra_src_buf;
+	/** Extra slices needed to store largest chunk + header. */
+	int num_extra_slices;
+	/** Contains the FEC-encoded data. */
+	unsigned char *enc_buf;
+};
+
+/**
+ * Get the chunk time of the current audio file.
+ *
+ * \return A pointer to a struct containing the chunk time, or NULL,
+ * if currently no audio file is selected.
+ */
+struct timeval *vss_chunk_time(void)
+{
+	if (mmd->afd.afhi.chunk_tv.tv_sec == 0 &&
+			mmd->afd.afhi.chunk_tv.tv_usec == 0)
+		return NULL;
+	return &mmd->afd.afhi.chunk_tv;
+}
+
+/**
+ * Write a fec header to a buffer.
+ *
+ * \param buf The buffer to write to.
+ * \param h The fec header to write.
+ */
+static void write_fec_header(struct fec_client *fc, struct vss_task *vsst)
+{
+	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 int num_slices(long unsigned bytes, struct fec_client *fc, uint8_t *result)
+{
+	unsigned long m = fc->fcp->max_slice_bytes - FEC_HEADER_SIZE;
+	unsigned rv, redundant_slices = fc->fcp->slices_per_group
+		- fc->fcp->data_slices_per_group;
+
+	if (!m)
+		return -E_BAD_CT;
+	rv = (bytes + m - 1) / m;
+	if (rv + redundant_slices > 255)
+		return -E_BAD_CT;
+	*result = rv;
+	return 1;
+}
+
+/* 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 setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
+{
+	int ret, i, k, data_slices;
+	size_t len;
+	const char *buf, *start_buf;
+	struct fec_group *g = &fc->group;
+	unsigned slice_bytes = fc->fcp->max_slice_bytes - FEC_HEADER_SIZE;
+	uint32_t max_data_size;
+
+	if (fc->first_stream_chunk < 0) {
+		uint8_t hs, ds; /* needed header/data slices */
+		uint8_t rs = fc->fcp->slices_per_group
+			- fc->fcp->data_slices_per_group; /* redundant slices */
+		int n;
+
+		ret = num_slices(vsst->header_len, fc, &hs);
+		if (ret < 0)
+			return ret;
+		ret = num_slices(afh_get_largest_chunk_size(&mmd->afd.afhi),
+			fc, &ds);
+		if (ret < 0)
+			return ret;
+		k = (int)hs + ds;
+		if (k > 255)
+			return -E_BAD_CT;
+		if (k < fc->fcp->data_slices_per_group)
+			k = fc->fcp->data_slices_per_group;
+		n = k + rs;
+		fc->num_extra_slices = k - fc->fcp->data_slices_per_group;
+		PARA_NOTICE_LOG("fec parms %d:%d:%d (%d extra slices)\n",
+			slice_bytes, k, n, fc->num_extra_slices);
+		fec_free(fc->parms);
+		fc->src_data = para_realloc(fc->src_data, k * sizeof(char *));
+		ret = fec_new(k, n, &fc->parms);
+		if (ret < 0)
+			return ret;
+		fc->stream_start = *now;
+		fc->first_stream_chunk = mmd->current_chunk;
+		g->first_chunk = mmd->current_chunk;
+		g->num = 0;
+		g->start = *now;
+	} else {
+		/*
+		 * Start and duration of this group depend only on the previous
+		 * group. Compute the new group start as g->start += g->duration.
+		 */
+		struct timeval tmp = g->start;
+		tv_add(&tmp, &g->duration, &g->start);
+		k = fc->fcp->data_slices_per_group + fc->num_extra_slices;
+		set_group_timing(fc, g);
+		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)) {
+		ret = num_slices(vsst->header_len, fc, &g->num_header_slices);
+		if (ret < 0)
+			return ret;
+	} 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;
+	if (g->num == 0)
+		set_group_timing(fc, g);
+
+	/* 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;
+	}
+	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
+	);
+	return 1;
+}
+
+static int compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst)
+{
+	assert(fc->error >= 0);
+	if (fc->first_stream_chunk < 0 || fc->current_slice_num
+			== fc->fcp->slices_per_group + fc->num_extra_slices) {
+		int ret = setup_next_fec_group(fc, vsst);
+		if (ret == 0)
+			return 0;
+		if (ret < 0) {
+			PARA_ERROR_LOG("%s\n", para_strerror(-ret));
+			PARA_ERROR_LOG("FEC client temporarily disabled\n");
+			fc->error = ret;
+			return fc->error;
+		}
+	}
+	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;
+}
+
+/**
+ * Return a buffer that marks the end of the stream.
+ *
+ * \param buf Result pointer.
+ * \return The length of the eof buffer.
+ *
+ * This is used for (multicast) udp streaming where closing the socket on the
+ * sender might not give rise to an eof condition at the peer.
+ */
+size_t vss_get_fec_eof_packet(const char **buf)
+{
+	static const char fec_eof_packet[FEC_HEADER_SIZE] = FEC_EOF_PACKET;
+	*buf = fec_eof_packet;
+	return FEC_HEADER_SIZE;
+}
+
+/**
+ * Add one entry to the list of active fec clients.
+ *
+ * \param fcp Describes the fec parameters to be used for this client.
+ * \param result An opaque pointer that must be used by remove the client later.
+ *
+ * \return Standard.
+ */
+int vss_add_fec_client(struct fec_client_parms *fcp, struct fec_client **result)
+{
+	int ret;
+	struct fec_client *fc;
+
+	if (fcp->max_slice_bytes < FEC_HEADER_SIZE + fcp->data_slices_per_group)
+		return -ERRNO_TO_PARA_ERROR(EINVAL);
+	fc = para_calloc(sizeof(*fc));
+	fc->fcp = fcp;
+	ret = fec_new(fcp->data_slices_per_group, fcp->slices_per_group,
+		&fc->parms);
+	if (ret < 0)
+		goto err;
+	fc->first_stream_chunk = -1; /* stream not yet started */
+	fc->src_data = para_malloc(fc->fcp->slices_per_group * sizeof(char *));
+	fc->enc_buf = para_calloc(fc->fcp->max_slice_bytes);
+	fc->num_extra_slices = 0;
+	fc->extra_src_buf = para_calloc(fc->fcp->max_slice_bytes);
+	fc->next_header_time.tv_sec = 0;
+	para_list_add(&fc->node, &fec_client_list);
+	*result = fc;
+	return 1;
+err:
+	fec_free(fc->parms);
+	free(fc);
+	*result = NULL;
+	return ret;
+}
+
+/**
+ * Remove one entry from the list of active fec clients.
+ *
+ * \param fc The client to be removed.
+ */
+void vss_del_fec_client(struct fec_client *fc)
+{
+	list_del(&fc->node);
+	free(fc->src_data);
+	free(fc->enc_buf);
+	free(fc->extra_src_buf);
+	fec_free(fc->parms);
+	free(fc);
+}
+
+/*
+ * Compute if/when next slice is due. If it isn't due yet and \a diff is
+ * not \p Null, compute the time difference next - now, where
+ *
+ *	next = stream_start + (first_group_chunk - first_stream_chunk)
+ *		* chunk_time + slice_num * slice_time
+ */
+static int next_slice_is_due(struct fec_client *fc, struct timeval *diff)
+{
+	struct timeval tmp, next;
+	int ret;
+
+	if (fc->first_stream_chunk < 0)
+		return 1;
+	tv_scale(fc->current_slice_num, &fc->group.slice_duration, &tmp);
+	tv_add(&tmp, &fc->group.start, &next);
+	ret = tv_diff(&next, now, diff);
+	return ret < 0? 1 : 0;
+}
+
+static void compute_slice_timeout(struct timeval *timeout)
+{
+	struct fec_client *fc;
+
+	assert(vss_playing());
+	list_for_each_entry(fc, &fec_client_list, node) {
+		struct timeval diff;
+
+		if (fc->error < 0)
+			continue;
+		if (next_slice_is_due(fc, &diff)) {
+			timeout->tv_sec = 0;
+			timeout->tv_usec = 0;
+			return;
+		}
+		/* timeout = min(timeout, diff) */
+		if (tv_diff(&diff, timeout, NULL) < 0)
+			*timeout = diff;
+	}
+}
+
+static void set_eof_barrier(struct vss_task *vsst)
+{
+	struct fec_client *fc;
+	struct timeval timeout = {1, 0}, *chunk_tv = vss_chunk_time();
+
+	if (!chunk_tv)
+		goto out;
+	list_for_each_entry(fc, &fec_client_list, node) {
+		struct timeval group_duration;
+
+		if (fc->error < 0)
+			continue;
+		tv_scale(fc->group.num_chunks, chunk_tv, &group_duration);
+		if (tv_diff(&timeout, &group_duration, NULL) < 0)
+			timeout = group_duration;
+	}
+out:
+	tv_add(now, &timeout, &vsst->eof_barrier);
+}
+
 /**
  * Check if vss status flag \a P (playing) is set.
  *
@@ -184,35 +614,34 @@ static struct timeval *vss_compute_timeout(struct vss_task *vsst)
 		return NULL;
 	compute_chunk_time(mmd->chunks_sent, &mmd->afd.afhi.chunk_tv,
 		&mmd->stream_start, &next_chunk);
-	if (chk_barrier("chunk", &next_chunk, &the_timeout, 0) < 0)
+	if (chk_barrier("chunk", &next_chunk, &the_timeout, 0) >= 0) {
+		/* chunk is due or bof */
+		the_timeout.tv_sec = 0;
+		the_timeout.tv_usec = 0;
 		return &the_timeout;
-	/* chunk is due or bof */
-	the_timeout.tv_sec = 0;
-	the_timeout.tv_usec = 0;
+	}
+	/* compute min of current timeout and next slice time */
+	compute_slice_timeout(&the_timeout);
 	return &the_timeout;
 }
 
 static void vss_eof(struct vss_task *vsst)
 {
-	mmd->stream_start = *now;
+
 	if (!vsst->map)
 		return;
 	if (mmd->new_vss_status_flags & VSS_NOMORE)
 		mmd->new_vss_status_flags = VSS_NEXT;
-	tv_add(&mmd->afd.afhi.eof_tv, now, &vsst->eof_barrier);
+	set_eof_barrier(vsst);
 	para_munmap(vsst->map, mmd->size);
 	vsst->map = NULL;
 	mmd->chunks_sent = 0;
-	mmd->offset = 0;
+	//mmd->offset = 0;
 	mmd->afd.afhi.seconds_total = 0;
 	mmd->afd.afhi.chunk_tv.tv_sec = 0;
 	mmd->afd.afhi.chunk_tv.tv_usec = 0;
 	free(mmd->afd.afhi.chunk_table);
 	mmd->afd.afhi.chunk_table = NULL;
-	free(mmd->afd.afhi.info_string);
-	mmd->afd.afhi.info_string = make_message("%s:\n%s:\n%s:\n", status_item_list[SI_AUDIO_FILE_INFO],
-		status_item_list[SI_TAGINFO1], status_item_list[SI_TAGINFO2]);
-	make_empty_status_items(mmd->afd.verbose_ls_output);
 	mmd->mtime = 0;
 	mmd->size = 0;
 	mmd->events++;
@@ -230,20 +659,6 @@ const char *supported_audio_formats(void)
 	return SUPPORTED_AUDIO_FORMATS;
 }
 
-/**
- * Get the chunk time of the current audio file.
- *
- * \return A pointer to a struct containing the chunk time, or NULL,
- * if currently no audio file is selected.
- */
-struct timeval *vss_chunk_time(void)
-{
-	if (mmd->afd.afhi.chunk_tv.tv_sec == 0 &&
-			mmd->afd.afhi.chunk_tv.tv_usec == 0)
-		return NULL;
-	return &mmd->afd.afhi.chunk_tv;
-}
-
 static int need_to_request_new_audio_file(struct vss_task *vsst)
 {
 	struct timeval diff;
@@ -262,11 +677,15 @@ static int need_to_request_new_audio_file(struct vss_task *vsst)
 	return 1;
 }
 
+static void set_mmd_offset(void)
+{
+	struct timeval offset;
+	tv_scale(mmd->current_chunk, &mmd->afd.afhi.chunk_tv, &offset);
+	mmd->offset = tv2ms(&offset);
+}
+
 /**
- * Compute the timeout for para_server's main select-loop.
- *
- * This function gets called from para_server to determine the timeout value
- * for its main select loop.
+ * Compute the timeout for the main select-loop of the scheduler.
  *
  * \param s Pointer to the server scheduler.
  * \param t Pointer to the vss task structure.
@@ -285,21 +704,31 @@ static void vss_pre_select(struct sched *s, struct task *t)
 	struct timeval *tv, diff;
 	struct vss_task *vsst = container_of(t, struct vss_task, task);
 
-	if (!vsst->map || vss_next() || vss_paused() || vss_repos())
+	if (!vsst->map || vss_next() || vss_paused() || vss_repos()) {
+		struct fec_client *fc, *tmp;
 		for (i = 0; senders[i].name; i++)
-			senders[i].shutdown_clients();
+			if (senders[i].shutdown_clients)
+				senders[i].shutdown_clients();
+		list_for_each_entry_safe(fc, tmp, &fec_client_list, node) {
+			fc->first_stream_chunk = -1;
+			fc->error = 0;
+		}
+		mmd->stream_start.tv_sec = 0;
+		mmd->stream_start.tv_usec = 0;
+	}
 	if (vss_next())
 		vss_eof(vsst);
 	else if (vss_paused()) {
 		if (mmd->chunks_sent)
-			tv_add(&mmd->afd.afhi.eof_tv, now, &vsst->eof_barrier);
+			set_eof_barrier(vsst);
 		mmd->chunks_sent = 0;
 	} else if (vss_repos()) {
 		tv_add(now, &vsst->announce_tv, &vsst->data_send_barrier);
-		tv_add(&mmd->afd.afhi.eof_tv, now, &vsst->eof_barrier);
+		set_eof_barrier(vsst);
 		mmd->chunks_sent = 0;
 		mmd->current_chunk = mmd->repos_request;
 		mmd->new_vss_status_flags &= ~VSS_REPOS;
+		set_mmd_offset();
 	}
 	if (need_to_request_new_audio_file(vsst)) {
 		PARA_DEBUG_LOG("ready and playing, but no audio file\n");
@@ -343,9 +772,9 @@ static int recv_afs_msg(int afs_socket, int *fd, uint32_t *code, uint32_t *data)
 	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 		if (cmsg->cmsg_level != SOL_SOCKET
 			|| cmsg->cmsg_type != SCM_RIGHTS)
-		continue;
+			continue;
 		if ((cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int) != 1)
-		continue;
+			continue;
 		*fd = *(int *)CMSG_DATA(cmsg);
 	}
 	return 1;
@@ -358,7 +787,6 @@ static void recv_afs_result(struct vss_task *vsst)
 	struct stat statbuf;
 
 	vsst->afsss = AFS_SOCKET_READY;
-	mmd->afd.afhi.chunk_table = NULL;
 	ret = recv_afs_msg(vsst->afs_socket, &passed_fd, &afs_code, &afs_data);
 	if (ret < 0)
 		goto err;
@@ -407,52 +835,74 @@ err:
 /**
  * Main sending function.
  *
- * This function gets called from para_server as soon as the next chunk of data
- * should be pushed out. It obtains a pointer to the data to be sent out as
- * well as its length from mmd->afd.afhi. This information is then passed to
- * each supported sender's send() function which is supposed to send out the data
- * to all connected clients.
+ * This function gets called from vss_post_select(). It checks whether the next
+ * chunk of data should be pushed out. It obtains a pointer to the data to be
+ * sent out as well as its length from mmd->afd.afhi. This information is then
+ * passed to each supported sender's send() function as well as to the send()
+ * functions of each registered fec client.
  */
-static void vss_send_chunk(struct vss_task *vsst)
+static void vss_send(struct vss_task *vsst)
 {
-	int i;
+	int i, fec_active = 0;
 	struct timeval due;
-	const char *buf;
-	size_t len;
+	struct fec_client *fc, *tmp_fc;
 
 	if (!vsst->map || !vss_playing())
 		return;
-	compute_chunk_time(mmd->chunks_sent, &mmd->afd.afhi.chunk_tv,
-		&mmd->stream_start, &due);
-	if (tv_diff(&due, now, NULL) > 0)
-		return;
 	if (chk_barrier("eof", &vsst->eof_barrier, &due, 1) < 0)
 		return;
 	if (chk_barrier("data send", &vsst->data_send_barrier,
 			&due, 1) < 0)
 		return;
+	list_for_each_entry_safe(fc, tmp_fc, &fec_client_list, node) {
+		if (fc->error < 0)
+			continue;
+		if (!next_slice_is_due(fc, NULL)) {
+			fec_active = 1;
+			continue;
+		}
+		if (compute_next_fec_slice(fc, vsst) <= 0)
+			continue;
+		PARA_DEBUG_LOG("sending %d:%d (%u bytes)\n", fc->group.num,
+			fc->current_slice_num, fc->fcp->max_slice_bytes);
+		fc->fcp->send((char *)fc->enc_buf,
+			fc->fcp->max_slice_bytes,
+			fc->fcp->private_data);
+		fc->current_slice_num++;
+		fec_active = 1;
+	}
 	if (mmd->current_chunk >= mmd->afd.afhi.chunks_total) { /* eof */
-		mmd->new_vss_status_flags |= VSS_NEXT;
+		if (!fec_active)
+			mmd->new_vss_status_flags |= VSS_NEXT;
 		return;
 	}
-	/*
-	 * We call the send function also in case of empty chunks as they
-	 * might have still some data queued which can be sent in this case.
-	 */
-	if (!mmd->chunks_sent) {
-		struct timeval tmp;
-		mmd->stream_start = *now;
-		tv_scale(mmd->current_chunk, &mmd->afd.afhi.chunk_tv, &tmp);
-		mmd->offset = tv2ms(&tmp);
-		mmd->events++;
+	compute_chunk_time(mmd->chunks_sent, &mmd->afd.afhi.chunk_tv,
+		&mmd->stream_start, &due);
+	if (tv_diff(&due, now, NULL) <= 0) {
+		const char *buf;
+		size_t len;
+
+		if (!mmd->chunks_sent) {
+			mmd->stream_start = *now;
+			mmd->events++;
+			set_mmd_offset();
+		}
+		/*
+		 * We call the send function also in case of empty chunks as
+		 * they might have still some data queued which can be sent in
+		 * this case.
+		 */
+		afh_get_chunk(mmd->current_chunk, &mmd->afd.afhi, vsst->map,
+			&buf, &len);
+		for (i = 0; senders[i].name; i++) {
+			if (!senders[i].send)
+				continue;
+			senders[i].send(mmd->current_chunk, mmd->chunks_sent,
+				buf, len, vsst->header_buf, vsst->header_len);
+		}
+		mmd->chunks_sent++;
+		mmd->current_chunk++;
 	}
-	afh_get_chunk(mmd->current_chunk, &mmd->afd.afhi, vsst->map, &buf, &len);
-	for (i = 0; senders[i].name; i++)
-		senders[i].send(mmd->current_chunk, mmd->chunks_sent, buf, len,
-			vsst->header_buf, vsst->header_len);
-	mmd->new_vss_status_flags |= VSS_PLAYING;
-	mmd->chunks_sent++;
-	mmd->current_chunk++;
 }
 
 static void vss_post_select(struct sched *s, struct task *t)
@@ -460,6 +910,7 @@ static void vss_post_select(struct sched *s, struct task *t)
 	int ret, i;
 	struct vss_task *vsst = container_of(t, struct vss_task, task);
 
+
 	if (mmd->sender_cmd_data.cmd_num >= 0) {
 		int num = mmd->sender_cmd_data.cmd_num,
 			sender_num = mmd->sender_cmd_data.sender_num;
@@ -474,7 +925,10 @@ static void vss_post_select(struct sched *s, struct task *t)
 	} else if (FD_ISSET(vsst->afs_socket, &s->wfds)) {
 		PARA_NOTICE_LOG("requesting new fd from afs\n");
 		ret = send_buffer(vsst->afs_socket, "new");
-		vsst->afsss = AFS_SOCKET_AFD_PENDING;
+		if (ret < 0)
+			PARA_CRIT_LOG("%s\n", para_strerror(-ret));
+		else
+			vsst->afsss = AFS_SOCKET_AFD_PENDING;
 	}
 	for (i = 0; senders[i].name; i++) {
 		if (!senders[i].post_select)
@@ -484,7 +938,7 @@ static void vss_post_select(struct sched *s, struct task *t)
 	if ((vss_playing() && !(mmd->vss_status_flags & VSS_PLAYING)) ||
 			(vss_next() && vss_playing()))
 		tv_add(now, &vsst->announce_tv, &vsst->data_send_barrier);
-	vss_send_chunk(vsst);
+	vss_send(vsst);
 }
 
 /**
@@ -504,12 +958,13 @@ void init_vss_task(int afs_socket)
 			conf.announce_time_arg : 300,
 		autoplay_delay = conf.autoplay_delay_arg > 0?
 			conf.autoplay_delay_arg : 0;
-
+	vsst->header_interval.tv_sec = 5; /* should this be configurable? */
 	vsst->afs_socket = afs_socket;
 	vsst->task.pre_select = vss_pre_select;
 	vsst->task.post_select = vss_post_select;
 	ms2tv(announce_time, &vsst->announce_tv);
 	PARA_INFO_LOG("announce timeval: %lums\n", tv2ms(&vsst->announce_tv));
+	INIT_LIST_HEAD(&fec_client_list);
 	for (i = 0; senders[i].name; i++) {
 		PARA_NOTICE_LOG("initializing %s sender\n", senders[i].name);
 		senders[i].init(&senders[i]);
@@ -517,7 +972,6 @@ void init_vss_task(int afs_socket)
 	free(hn);
 	free(home);
 	mmd->sender_cmd_data.cmd_num = -1;
-	make_empty_status_items(mmd->afd.verbose_ls_output);
 	if (conf.autoplay_given) {
 		struct timeval tmp;
 		mmd->vss_status_flags |= VSS_PLAYING;