gui: Use variable-sized input buffer for the audiod pipe.
[paraslash.git] / vss.c
diff --git a/vss.c b/vss.c
index 48bfa7d..57e531e 100644 (file)
--- a/vss.c
+++ b/vss.c
  */
 
 #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"
@@ -65,18 +68,442 @@ enum afs_socket_status {
 
 /** The task structure for the virtual streaming system. */
 struct vss_task {
+       /** Copied from the -announce_time command line option. */
        struct timeval announce_tv;
+       /** End of the announcing interval. */
        struct timeval data_send_barrier;
+       /** End of the EOF interval. */
        struct timeval eof_barrier;
+       /** Only used if --autoplay_delay was given. */
        struct timeval autoplay_barrier;
+       /** Used for afs-server communication. */
        int afs_socket;
+       /** The current state of \a afs_socket. */
        enum afs_socket_status afsss;
+       /** The memory mapped audio file. */
        char *map;
+       /** Used by the scheduler. */
        struct task task;
+       /** Pointer to the header of the mapped audio file. */
        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 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;
+}
+
+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 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, want;
+
+               ret = num_slices(largest, fc, &needed);
+               if (ret < 0)
+                       return ret;
+               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) {
+                       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)) {
+               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;
+
+       /* 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)
+{
+       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.
  *
@@ -174,22 +601,25 @@ 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;
@@ -199,10 +629,6 @@ static void vss_eof(struct vss_task *vsst)
        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++;
@@ -220,22 +646,10 @@ 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;
+
        if (vsst->map) /* have audio file */
                return 0;
        if (!vss_playing()) /* don't need one */
@@ -244,14 +658,14 @@ static int need_to_request_new_audio_file(struct vss_task *vsst)
                return 0;
        if (vsst->afsss == AFS_SOCKET_AFD_PENDING) /* already requested one */
                return 0;
+       if (chk_barrier("autoplay_delay", &vsst->autoplay_barrier,
+                       &diff, 1) < 0)
+               return 0;
        return 1;
 }
 
 /**
- * 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.
@@ -270,17 +684,27 @@ 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(&mmd->afd.afhi.eof_tv, now, &vsst->eof_barrier);
+               tv_add(now, &vsst->announce_tv, &vsst->data_send_barrier);
+               set_eof_barrier(vsst);
                mmd->chunks_sent = 0;
                mmd->current_chunk = mmd->repos_request;
                mmd->new_vss_status_flags &= ~VSS_REPOS;
@@ -327,9 +751,9 @@ 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;
@@ -342,7 +766,6 @@ 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;
@@ -366,8 +789,10 @@ static void recv_afs_result(struct vss_task *vsst)
        }
        mmd->size = statbuf.st_size;
        mmd->mtime = statbuf.st_mtime;
-       vsst->map = para_mmap(mmd->size, PROT_READ, MAP_PRIVATE,
-               passed_fd, 0);
+       ret = para_mmap(mmd->size, PROT_READ, MAP_PRIVATE, passed_fd,
+               0, &vsst->map);
+       if (ret < 0)
+               goto err;
        close(passed_fd);
        mmd->chunks_sent = 0;
        mmd->current_chunk = 0;
@@ -389,52 +814,74 @@ 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, sent_something = 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))
+                       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++;
+               sent_something = 1;
+       }
        if (mmd->current_chunk >= mmd->afd.afhi.chunks_total) { /* eof */
-               mmd->new_vss_status_flags |= VSS_NEXT;
+               if (!sent_something)
+                       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) {
+                       struct timeval tmp;
+                       mmd->stream_start = *now;
+                       tv_scale(mmd->current_chunk, &mmd->afd.afhi.chunk_tv, &tmp);
+                       mmd->offset = tv2ms(&tmp);
+                       mmd->events++;
+               }
+               /*
+                * 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)
@@ -442,6 +889,7 @@ 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;
@@ -456,16 +904,20 @@ 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)
                        continue;
                senders[i].post_select(&s->rfds, &s->wfds);
        }
-       if (vss_playing() && !(mmd->vss_status_flags & VSS_PLAYING))
+       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);
 }
 
 /**
@@ -485,12 +937,13 @@ 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]);
@@ -498,13 +951,14 @@ 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;
                mmd->new_vss_status_flags |= VSS_PLAYING;
                ms2tv(autoplay_delay, &tmp);
                tv_add(now, &tmp, &vsst->autoplay_barrier);
+               tv_add(&vsst->autoplay_barrier, &vsst->announce_tv,
+                       &vsst->data_send_barrier);
        }
        register_task(&vsst->task);
 }