really create glitch-free branch

git-svn-id: file:///home/lennart/svn/public/pulseaudio/branches/glitch-free@2120 fefdeb5f-60dc-0310-8127-8f9354f1896f

1 files changed, 1193 insertions, 0 deletions

diff --git a/src/modules/module-combine.c b/src/modules/module-combine.c
new file mode 100644
index 00000000..996cd4f6
--- /dev/null
+++ b/src/modules/module-combine.c
@@ -0,0 +1,1193 @@
+/* $Id$ */
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2004-2006 Lennart Poettering
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as published
+  by the Free Software Foundation; either version 2 of the License,
+  or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+
+#include <pulse/timeval.h>
+#include <pulse/xmalloc.h>
+
+#include <pulsecore/macro.h>
+#include <pulsecore/module.h>
+#include <pulsecore/llist.h>
+#include <pulsecore/sink.h>
+#include <pulsecore/sink-input.h>
+#include <pulsecore/memblockq.h>
+#include <pulsecore/log.h>
+#include <pulsecore/core-util.h>
+#include <pulsecore/modargs.h>
+#include <pulsecore/namereg.h>
+#include <pulsecore/mutex.h>
+#include <pulsecore/thread.h>
+#include <pulsecore/thread-mq.h>
+#include <pulsecore/rtpoll.h>
+#include <pulsecore/rtclock.h>
+#include <pulsecore/core-error.h>
+
+#include "module-combine-symdef.h"
+
+PA_MODULE_AUTHOR("Lennart Poettering");
+PA_MODULE_DESCRIPTION("Combine multiple sinks to one");
+PA_MODULE_VERSION(PACKAGE_VERSION);
+PA_MODULE_LOAD_ONCE(FALSE);
+PA_MODULE_USAGE(
+        "sink_name=<name for the sink> "
+        "master=<master sink> "
+        "slaves=<slave sinks> "
+        "adjust_time=<seconds> "
+        "resample_method=<method> "
+        "format=<sample format> "
+        "channels=<number of channels> "
+        "rate=<sample rate> "
+        "channel_map=<channel map>");
+
+#define DEFAULT_SINK_NAME "combined"
+#define MEMBLOCKQ_MAXLENGTH (1024*170)
+
+#define DEFAULT_ADJUST_TIME 10
+
+static const char* const valid_modargs[] = {
+    "sink_name",
+    "master",
+    "slaves",
+    "adjust_time",
+    "resample_method",
+    "format",
+    "channels",
+    "rate",
+    "channel_map",
+    NULL
+};
+
+struct output {
+    struct userdata *userdata;
+
+    pa_sink *sink;
+    pa_sink_input *sink_input;
+
+    pa_asyncmsgq *inq,    /* Message queue from the sink thread to this sink input */
+                 *outq;   /* Message queue from this sink input to the sink thread */
+    pa_rtpoll_item *inq_rtpoll_item, *outq_rtpoll_item;
+
+    pa_memblockq *memblockq;
+
+    pa_usec_t total_latency;
+
+    PA_LLIST_FIELDS(struct output);
+};
+
+struct userdata {
+    pa_core *core;
+    pa_module *module;
+    pa_sink *sink;
+
+    pa_thread *thread;
+    pa_thread_mq thread_mq;
+    pa_rtpoll *rtpoll;
+
+    pa_time_event *time_event;
+    uint32_t adjust_time;
+
+    pa_bool_t automatic;
+    size_t block_size;
+
+    pa_hook_slot *sink_new_slot, *sink_unlink_slot, *sink_state_changed_slot;
+
+    pa_resample_method_t resample_method;
+
+    struct timeval adjust_timestamp;
+
+    struct output *master;
+    pa_idxset* outputs; /* managed in main context */
+
+    struct {
+        PA_LLIST_HEAD(struct output, active_outputs); /* managed in IO thread context */
+        pa_atomic_t running;  /* we cache that value here, so that every thread can query it cheaply */
+        struct timeval timestamp;
+        pa_bool_t in_null_mode;
+    } thread_info;
+};
+
+enum {
+    SINK_MESSAGE_ADD_OUTPUT = PA_SINK_MESSAGE_MAX,
+    SINK_MESSAGE_REMOVE_OUTPUT,
+    SINK_MESSAGE_NEED
+};
+
+enum {
+    SINK_INPUT_MESSAGE_POST = PA_SINK_INPUT_MESSAGE_MAX
+};
+
+static void output_free(struct output *o);
+static int output_create_sink_input(struct output *o);
+static void update_master(struct userdata *u, struct output *o);
+static void pick_master(struct userdata *u, struct output *except);
+
+static void adjust_rates(struct userdata *u) {
+    struct output *o;
+    pa_usec_t max_sink_latency = 0, min_total_latency = (pa_usec_t) -1, target_latency;
+    uint32_t base_rate;
+    uint32_t idx;
+
+    pa_assert(u);
+    pa_sink_assert_ref(u->sink);
+
+    if (pa_idxset_size(u->outputs) <= 0)
+        return;
+
+    if (!u->master)
+        return;
+
+    if (!PA_SINK_OPENED(pa_sink_get_state(u->sink)))
+        return;
+
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx)) {
+        pa_usec_t sink_latency;
+
+        if (!o->sink_input || !PA_SINK_OPENED(pa_sink_get_state(o->sink)))
+            continue;
+
+        sink_latency = pa_sink_get_latency(o->sink);
+        o->total_latency = sink_latency + pa_sink_input_get_latency(o->sink_input);
+
+        if (sink_latency > max_sink_latency)
+            max_sink_latency = sink_latency;
+
+        if (min_total_latency == (pa_usec_t) -1 || o->total_latency < min_total_latency)
+            min_total_latency = o->total_latency;
+    }
+
+    if (min_total_latency == (pa_usec_t) -1)
+        return;
+
+    target_latency = max_sink_latency > min_total_latency ? max_sink_latency : min_total_latency;
+
+    pa_log_info("[%s] target latency is %0.0f usec.", u->sink->name, (float) target_latency);
+    pa_log_info("[%s] master %s latency %0.0f usec.", u->sink->name, u->master->sink->name, (float) u->master->total_latency);
+
+    base_rate = u->sink->sample_spec.rate;
+
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx)) {
+        uint32_t r = base_rate;
+
+        if (!o->sink_input || !PA_SINK_OPENED(pa_sink_get_state(o->sink)))
+            continue;
+
+        if (o->total_latency < target_latency)
+            r -= (uint32_t) (((((double) target_latency - o->total_latency))/u->adjust_time)*r/PA_USEC_PER_SEC);
+        else if (o->total_latency > target_latency)
+            r += (uint32_t) (((((double) o->total_latency - target_latency))/u->adjust_time)*r/PA_USEC_PER_SEC);
+
+        if (r < (uint32_t) (base_rate*0.9) || r > (uint32_t) (base_rate*1.1)) {
+            pa_log_warn("[%s] sample rates too different, not adjusting (%u vs. %u).", o->sink_input->name, base_rate, r);
+            pa_sink_input_set_rate(o->sink_input, base_rate);
+        } else {
+            pa_log_info("[%s] new rate is %u Hz; ratio is %0.3f; latency is %0.0f usec.", o->sink_input->name, r, (double) r / base_rate, (float) o->total_latency);
+            pa_sink_input_set_rate(o->sink_input, r);
+        }
+    }
+}
+
+static void time_callback(pa_mainloop_api*a, pa_time_event* e, const struct timeval *tv, void *userdata) {
+    struct userdata *u = userdata;
+    struct timeval n;
+
+    pa_assert(u);
+    pa_assert(a);
+    pa_assert(u->time_event == e);
+
+    adjust_rates(u);
+
+    pa_gettimeofday(&n);
+    n.tv_sec += u->adjust_time;
+    u->sink->core->mainloop->time_restart(e, &n);
+}
+
+static void thread_func(void *userdata) {
+    struct userdata *u = userdata;
+
+    pa_assert(u);
+
+    pa_log_debug("Thread starting up");
+
+    if (u->core->realtime_scheduling)
+        pa_make_realtime(u->core->realtime_priority+1);
+
+    pa_thread_mq_install(&u->thread_mq);
+    pa_rtpoll_install(u->rtpoll);
+
+    pa_rtclock_get(&u->thread_info.timestamp);
+    u->thread_info.in_null_mode = FALSE;
+
+    for (;;) {
+        int ret;
+
+        /* If no outputs are connected, render some data and drop it immediately. */
+        if (u->sink->thread_info.state == PA_SINK_RUNNING && !u->thread_info.active_outputs) {
+            struct timeval now;
+
+            pa_rtclock_get(&now);
+
+            if (!u->thread_info.in_null_mode || pa_timeval_cmp(&u->thread_info.timestamp, &now) <= 0) {
+                pa_sink_skip(u->sink, u->block_size);
+
+                if (!u->thread_info.in_null_mode)
+                    u->thread_info.timestamp = now;
+
+                pa_timeval_add(&u->thread_info.timestamp, pa_bytes_to_usec(u->block_size, &u->sink->sample_spec));
+            }
+
+            pa_rtpoll_set_timer_absolute(u->rtpoll, &u->thread_info.timestamp);
+            u->thread_info.in_null_mode = TRUE;
+
+        } else {
+            pa_rtpoll_set_timer_disabled(u->rtpoll);
+            u->thread_info.in_null_mode = FALSE;
+        }
+
+        /* Hmm, nothing to do. Let's sleep */
+        if ((ret = pa_rtpoll_run(u->rtpoll, TRUE)) < 0) {
+            pa_log_info("pa_rtpoll_run() = %i", ret);
+            goto fail;
+        }
+
+        if (ret == 0)
+            goto finish;
+    }
+
+fail:
+    /* If this was no regular exit from the loop we have to continue
+     * processing messages until we received PA_MESSAGE_SHUTDOWN */
+    pa_asyncmsgq_post(u->thread_mq.outq, PA_MSGOBJECT(u->core), PA_CORE_MESSAGE_UNLOAD_MODULE, u->module, 0, NULL, NULL);
+    pa_asyncmsgq_wait_for(u->thread_mq.inq, PA_MESSAGE_SHUTDOWN);
+
+finish:
+    pa_log_debug("Thread shutting down");
+}
+
+/* Called from I/O thread context */
+static void render_memblock(struct userdata *u, struct output *o, size_t length) {
+    pa_assert(u);
+    pa_assert(o);
+
+    /* We are run by the sink thread, on behalf of an output (o). The
+     * other output is waiting for us, hence it is safe to access its
+     * mainblockq and asyncmsgq directly. */
+
+    /* If we are not running, we cannot produce any data */
+    if (!pa_atomic_load(&u->thread_info.running))
+        return;
+
+    /* Maybe there's some data in the requesting output's queue
+     * now? */
+    while (pa_asyncmsgq_process_one(o->inq) > 0)
+        ;
+
+    /* Ok, now let's prepare some data if we really have to */
+    while (!pa_memblockq_is_readable(o->memblockq)) {
+        struct output *j;
+        pa_memchunk chunk;
+
+        /* Render data! */
+        pa_sink_render(u->sink, length, &chunk);
+
+        /* OK, let's send this data to the other threads */
+        for (j = u->thread_info.active_outputs; j; j = j->next)
+
+            /* Send to other outputs, which are not the requesting
+             * one */
+
+            if (j != o)
+                pa_asyncmsgq_post(j->inq, PA_MSGOBJECT(j->sink_input), SINK_INPUT_MESSAGE_POST, NULL, 0, &chunk, NULL);
+
+        /* And place it directly into the requesting output's queue */
+        if (o)
+            pa_memblockq_push_align(o->memblockq, &chunk);
+
+        pa_memblock_unref(chunk.memblock);
+    }
+}
+
+/* Called from I/O thread context */
+static void request_memblock(struct output *o, size_t length) {
+    pa_assert(o);
+    pa_sink_input_assert_ref(o->sink_input);
+    pa_sink_assert_ref(o->userdata->sink);
+
+    /* If another thread already prepared some data we received
+     * the data over the asyncmsgq, hence let's first process
+     * it. */
+    while (pa_asyncmsgq_process_one(o->inq) > 0)
+        ;
+
+    /* Check whether we're now readable */
+    if (pa_memblockq_is_readable(o->memblockq))
+        return;
+
+    /* OK, we need to prepare new data, but only if the sink is actually running */
+    if (pa_atomic_load(&o->userdata->thread_info.running))
+        pa_asyncmsgq_send(o->outq, PA_MSGOBJECT(o->userdata->sink), SINK_MESSAGE_NEED, o, length, NULL);
+}
+
+/* Called from I/O thread context */
+static int sink_input_peek_cb(pa_sink_input *i, size_t length, pa_memchunk *chunk) {
+    struct output *o;
+
+    pa_sink_input_assert_ref(i);
+    pa_assert_se(o = i->userdata);
+
+    /* If necessary, get some new data */
+    request_memblock(o, length);
+
+    return pa_memblockq_peek(o->memblockq, chunk);
+}
+
+/* Called from I/O thread context */
+static void sink_input_drop_cb(pa_sink_input *i, size_t length) {
+    struct output *o;
+
+    pa_sink_input_assert_ref(i);
+    pa_assert(length > 0);
+    pa_assert_se(o = i->userdata);
+
+    pa_memblockq_drop(o->memblockq, length);
+}
+
+/* Called from I/O thread context */
+static void sink_input_attach_cb(pa_sink_input *i) {
+    struct output *o;
+
+    pa_sink_input_assert_ref(i);
+    pa_assert_se(o = i->userdata);
+
+    /* Set up the queue from the sink thread to us */
+    pa_assert(!o->inq_rtpoll_item);
+    o->inq_rtpoll_item = pa_rtpoll_item_new_asyncmsgq(
+            i->sink->rtpoll,
+            PA_RTPOLL_LATE,  /* This one is not that important, since we check for data in _peek() anyway. */
+            o->inq);
+}
+
+/* Called from I/O thread context */
+static void sink_input_detach_cb(pa_sink_input *i) {
+    struct output *o;
+
+    pa_sink_input_assert_ref(i);
+    pa_assert_se(o = i->userdata);
+
+    /* Shut down the queue from the sink thread to us */
+    pa_assert(o->inq_rtpoll_item);
+    pa_rtpoll_item_free(o->inq_rtpoll_item);
+    o->inq_rtpoll_item = NULL;
+}
+
+/* Called from main context */
+static void sink_input_kill_cb(pa_sink_input *i) {
+    struct output *o;
+
+    pa_sink_input_assert_ref(i);
+    pa_assert(o = i->userdata);
+
+    pa_module_unload_request(o->userdata->module);
+    output_free(o);
+}
+
+/* Called from thread context */
+static int sink_input_process_msg(pa_msgobject *obj, int code, void *data, int64_t offset, pa_memchunk *chunk) {
+    struct output *o = PA_SINK_INPUT(obj)->userdata;
+
+    switch (code) {
+
+        case PA_SINK_INPUT_MESSAGE_GET_LATENCY: {
+             pa_usec_t *r = data;
+
+            *r = pa_bytes_to_usec(pa_memblockq_get_length(o->memblockq), &o->sink_input->sample_spec);
+
+            /* Fall through, the default handler will add in the extra
+             * latency added by the resampler */
+            break;
+        }
+
+        case SINK_INPUT_MESSAGE_POST:
+
+            if (PA_SINK_OPENED(o->sink_input->sink->thread_info.state))
+                pa_memblockq_push_align(o->memblockq, chunk);
+            else
+                pa_memblockq_flush(o->memblockq);
+
+            break;
+    }
+
+    return pa_sink_input_process_msg(obj, code, data, offset, chunk);
+}
+
+/* Called from main context */
+static void disable_output(struct output *o) {
+    pa_assert(o);
+
+    if (!o->sink_input)
+        return;
+
+    pa_asyncmsgq_send(o->userdata->sink->asyncmsgq, PA_MSGOBJECT(o->userdata->sink), SINK_MESSAGE_REMOVE_OUTPUT, o, 0, NULL);
+    pa_sink_input_unlink(o->sink_input);
+    pa_sink_input_unref(o->sink_input);
+    o->sink_input = NULL;
+
+}
+
+/* Called from main context */
+static void enable_output(struct output *o) {
+    pa_assert(o);
+
+    if (o->sink_input)
+        return;
+
+    if (output_create_sink_input(o) >= 0) {
+
+        pa_memblockq_flush(o->memblockq);
+
+        pa_sink_input_put(o->sink_input);
+
+        if (o->userdata->sink && PA_SINK_LINKED(pa_sink_get_state(o->userdata->sink)))
+            pa_asyncmsgq_send(o->userdata->sink->asyncmsgq, PA_MSGOBJECT(o->userdata->sink), SINK_MESSAGE_ADD_OUTPUT, o, 0, NULL);
+    }
+}
+
+/* Called from main context */
+static void suspend(struct userdata *u) {
+    struct output *o;
+    uint32_t idx;
+
+    pa_assert(u);
+
+    /* Let's suspend by unlinking all streams */
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx))
+        disable_output(o);
+
+    pick_master(u, NULL);
+
+    pa_log_info("Device suspended...");
+}
+
+/* Called from main context */
+static void unsuspend(struct userdata *u) {
+    struct output *o;
+    uint32_t idx;
+
+    pa_assert(u);
+
+    /* Let's resume */
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx)) {
+
+        pa_sink_suspend(o->sink, FALSE);
+
+        if (PA_SINK_OPENED(pa_sink_get_state(o->sink)))
+            enable_output(o);
+    }
+
+    pick_master(u, NULL);
+
+    pa_log_info("Resumed successfully...");
+}
+
+/* Called from main context */
+static int sink_set_state(pa_sink *sink, pa_sink_state_t state) {
+    struct userdata *u;
+
+    pa_sink_assert_ref(sink);
+    pa_assert_se(u = sink->userdata);
+
+    /* Please note that in contrast to the ALSA modules we call
+     * suspend/unsuspend from main context here! */
+
+    switch (state) {
+        case PA_SINK_SUSPENDED:
+            pa_assert(PA_SINK_OPENED(pa_sink_get_state(u->sink)));
+
+            suspend(u);
+            break;
+
+        case PA_SINK_IDLE:
+        case PA_SINK_RUNNING:
+
+            if (pa_sink_get_state(u->sink) == PA_SINK_SUSPENDED)
+                unsuspend(u);
+
+            break;
+
+        case PA_SINK_UNLINKED:
+        case PA_SINK_INIT:
+            ;
+    }
+
+    return 0;
+}
+
+/* Called from thread context of the master */
+static int sink_process_msg(pa_msgobject *o, int code, void *data, int64_t offset, pa_memchunk *chunk) {
+    struct userdata *u = PA_SINK(o)->userdata;
+
+    switch (code) {
+
+        case PA_SINK_MESSAGE_SET_STATE:
+            pa_atomic_store(&u->thread_info.running, PA_PTR_TO_UINT(data) == PA_SINK_RUNNING);
+            break;
+
+        case PA_SINK_MESSAGE_GET_LATENCY:
+
+            /* This code will only be called when running in NULL
+             * mode, i.e. when no output is attached. See
+             * sink_get_latency_cb() below */
+
+            if (u->thread_info.in_null_mode) {
+                struct timeval now;
+
+                if (pa_timeval_cmp(&u->thread_info.timestamp, pa_rtclock_get(&now)) > 0) {
+                    *((pa_usec_t*) data) = pa_timeval_diff(&u->thread_info.timestamp, &now);
+                    break;
+                }
+            }
+
+            *((pa_usec_t*) data) = 0;
+
+            break;
+
+        case SINK_MESSAGE_ADD_OUTPUT: {
+            struct output *op = data;
+
+            PA_LLIST_PREPEND(struct output, u->thread_info.active_outputs, op);
+
+            pa_assert(!op->outq_rtpoll_item);
+
+            /* Create pa_asyncmsgq to the sink thread */
+
+            op->outq_rtpoll_item = pa_rtpoll_item_new_asyncmsgq(
+                    u->rtpoll,
+                    PA_RTPOLL_EARLY-1,  /* This item is very important */
+                    op->outq);
+
+            return 0;
+        }
+
+        case SINK_MESSAGE_REMOVE_OUTPUT: {
+            struct output *op = data;
+
+            PA_LLIST_REMOVE(struct output, u->thread_info.active_outputs, op);
+
+            /* Remove the q that leads from this output to the sink thread */
+
+            pa_assert(op->outq_rtpoll_item);
+            pa_rtpoll_item_free(op->outq_rtpoll_item);
+            op->outq_rtpoll_item = NULL;
+
+            return 0;
+        }
+
+        case SINK_MESSAGE_NEED:
+            render_memblock(u, data, (size_t) offset);
+            return 0;
+    }
+
+    return pa_sink_process_msg(o, code, data, offset, chunk);
+}
+
+/* Called from main context */
+static pa_usec_t sink_get_latency_cb(pa_sink *s) {
+    struct userdata *u;
+
+    pa_sink_assert_ref(s);
+    pa_assert_se(u = s->userdata);
+
+    if (u->master) {
+        /* If we have a master sink, we just return the latency of it
+         * and add our own buffering on top */
+
+        if (!u->master->sink_input)
+            return 0;
+
+        return
+            pa_sink_input_get_latency(u->master->sink_input) +
+            pa_sink_get_latency(u->master->sink);
+
+    } else {
+        pa_usec_t usec = 0;
+
+        /* We have no master, hence let's ask our own thread which
+         * implements the NULL sink */
+
+        if (pa_asyncmsgq_send(s->asyncmsgq, PA_MSGOBJECT(s), PA_SINK_MESSAGE_GET_LATENCY, &usec, 0, NULL) < 0)
+            return 0;
+
+        return usec;
+    }
+}
+
+static void update_description(struct userdata *u) {
+    int first = 1;
+    char *t;
+    struct output *o;
+    uint32_t idx;
+
+    pa_assert(u);
+
+    if (pa_idxset_isempty(u->outputs)) {
+        pa_sink_set_description(u->sink, "Simultaneous output");
+        return;
+    }
+
+    t = pa_xstrdup("Simultaneous output to");
+
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx)) {
+        char *e;
+
+        if (first) {
+            e = pa_sprintf_malloc("%s %s", t, o->sink->description);
+            first = 0;
+        } else
+            e = pa_sprintf_malloc("%s, %s", t, o->sink->description);
+
+        pa_xfree(t);
+        t = e;
+    }
+
+    pa_sink_set_description(u->sink, t);
+    pa_xfree(t);
+}
+
+static void update_master(struct userdata *u, struct output *o) {
+    pa_assert(u);
+
+    if (u->master == o)
+        return;
+
+    if ((u->master = o))
+        pa_log_info("Master sink is now '%s'", o->sink_input->sink->name);
+    else
+        pa_log_info("No master selected, lacking suitable outputs.");
+}
+
+static void pick_master(struct userdata *u, struct output *except) {
+    struct output *o;
+    uint32_t idx;
+    pa_assert(u);
+
+    if (u->master &&
+        u->master != except &&
+        u->master->sink_input &&
+        PA_SINK_OPENED(pa_sink_get_state(u->master->sink))) {
+        update_master(u, u->master);
+        return;
+    }
+
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx))
+        if (o != except &&
+            o->sink_input &&
+            PA_SINK_OPENED(pa_sink_get_state(o->sink))) {
+            update_master(u, o);
+            return;
+        }
+
+    update_master(u, NULL);
+}
+
+static int output_create_sink_input(struct output *o) {
+    pa_sink_input_new_data data;
+    char *t;
+
+    pa_assert(o);
+
+    if (o->sink_input)
+        return 0;
+
+    t = pa_sprintf_malloc("Simultaneous output on %s", o->sink->description);
+
+    pa_sink_input_new_data_init(&data);
+    data.sink = o->sink;
+    data.driver = __FILE__;
+    data.name = t;
+    pa_sink_input_new_data_set_sample_spec(&data, &o->userdata->sink->sample_spec);
+    pa_sink_input_new_data_set_channel_map(&data, &o->userdata->sink->channel_map);
+    data.module = o->userdata->module;
+    data.resample_method = o->userdata->resample_method;
+
+    o->sink_input = pa_sink_input_new(o->userdata->core, &data, PA_SINK_INPUT_VARIABLE_RATE|PA_SINK_INPUT_DONT_MOVE);
+
+    pa_xfree(t);
+
+    if (!o->sink_input)
+        return -1;
+
+    o->sink_input->parent.process_msg = sink_input_process_msg;
+    o->sink_input->peek = sink_input_peek_cb;
+    o->sink_input->drop = sink_input_drop_cb;
+    o->sink_input->attach = sink_input_attach_cb;
+    o->sink_input->detach = sink_input_detach_cb;
+    o->sink_input->kill = sink_input_kill_cb;
+    o->sink_input->userdata = o;
+
+
+    return 0;
+}
+
+static struct output *output_new(struct userdata *u, pa_sink *sink) {
+    struct output *o;
+
+    pa_assert(u);
+    pa_assert(sink);
+    pa_assert(u->sink);
+
+    o = pa_xnew(struct output, 1);
+    o->userdata = u;
+    o->inq = pa_asyncmsgq_new(0);
+    o->outq = pa_asyncmsgq_new(0);
+    o->inq_rtpoll_item = NULL;
+    o->outq_rtpoll_item = NULL;
+    o->sink = sink;
+    o->sink_input = NULL;
+    o->memblockq = pa_memblockq_new(
+            0,
+            MEMBLOCKQ_MAXLENGTH,
+            MEMBLOCKQ_MAXLENGTH,
+            pa_frame_size(&u->sink->sample_spec),
+            1,
+            0,
+            NULL);
+
+    pa_assert_se(pa_idxset_put(u->outputs, o, NULL) == 0);
+
+    if (u->sink && PA_SINK_LINKED(pa_sink_get_state(u->sink)))
+        pa_asyncmsgq_send(u->sink->asyncmsgq, PA_MSGOBJECT(u->sink), SINK_MESSAGE_ADD_OUTPUT, o, 0, NULL);
+    else {
+        /* If the sink is not yet started, we need to do the activation ourselves */
+        PA_LLIST_PREPEND(struct output, u->thread_info.active_outputs, o);
+
+        o->outq_rtpoll_item = pa_rtpoll_item_new_asyncmsgq(
+                u->rtpoll,
+                PA_RTPOLL_EARLY-1,  /* This item is very important */
+                o->outq);
+    }
+
+    if (PA_SINK_OPENED(pa_sink_get_state(u->sink)) || pa_sink_get_state(u->sink) == PA_SINK_INIT) {
+        pa_sink_suspend(sink, FALSE);
+
+        if (PA_SINK_OPENED(pa_sink_get_state(sink)))
+            if (output_create_sink_input(o) < 0)
+                goto fail;
+    }
+
+
+    update_description(u);
+
+    return o;
+
+fail:
+
+    if (o) {
+        pa_idxset_remove_by_data(u->outputs, o, NULL);
+
+        if (o->sink_input) {
+            pa_sink_input_unlink(o->sink_input);
+            pa_sink_input_unref(o->sink_input);
+        }
+
+        if (o->memblockq)
+            pa_memblockq_free(o->memblockq);
+
+        if (o->inq)
+            pa_asyncmsgq_unref(o->inq);
+
+        if (o->outq)
+            pa_asyncmsgq_unref(o->outq);
+
+        pa_xfree(o);
+    }
+
+    return NULL;
+}
+
+static pa_hook_result_t sink_new_hook_cb(pa_core *c, pa_sink *s, struct userdata* u) {
+    struct output *o;
+
+    pa_core_assert_ref(c);
+    pa_sink_assert_ref(s);
+    pa_assert(u);
+    pa_assert(u->automatic);
+
+    if (!(s->flags & PA_SINK_HARDWARE) || s == u->sink)
+        return PA_HOOK_OK;
+
+    pa_log_info("Configuring new sink: %s", s->name);
+
+    if (!(o = output_new(u, s))) {
+        pa_log("Failed to create sink input on sink '%s'.", s->name);
+        return PA_HOOK_OK;
+    }
+
+    if (o->sink_input)
+        pa_sink_input_put(o->sink_input);
+
+    pick_master(u, NULL);
+
+    return PA_HOOK_OK;
+}
+
+static pa_hook_result_t sink_unlink_hook_cb(pa_core *c, pa_sink *s, struct userdata* u) {
+    struct output *o;
+    uint32_t idx;
+
+    pa_assert(c);
+    pa_sink_assert_ref(s);
+    pa_assert(u);
+
+    if (s == u->sink)
+        return PA_HOOK_OK;
+
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx))
+        if (o->sink == s)
+            break;
+
+    if (!o)
+        return PA_HOOK_OK;
+
+    pa_log_info("Unconfiguring sink: %s", s->name);
+
+    output_free(o);
+
+    return PA_HOOK_OK;
+}
+
+static pa_hook_result_t sink_state_changed_hook_cb(pa_core *c, pa_sink *s, struct userdata* u) {
+    struct output *o;
+    uint32_t idx;
+    pa_sink_state_t state;
+
+    if (s == u->sink)
+        return PA_HOOK_OK;
+
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx))
+        if (o->sink == s)
+            break;
+
+    if (!o)
+        return PA_HOOK_OK;
+
+    state = pa_sink_get_state(s);
+
+    if (PA_SINK_OPENED(state) && PA_SINK_OPENED(pa_sink_get_state(u->sink)) && !o->sink_input) {
+        enable_output(o);
+        pick_master(u, NULL);
+    }
+
+    if (state == PA_SINK_SUSPENDED && o->sink_input) {
+        disable_output(o);
+        pick_master(u, o);
+    }
+
+    return PA_HOOK_OK;
+}
+
+int pa__init(pa_module*m) {
+    struct userdata *u;
+    pa_modargs *ma = NULL;
+    const char *master_name, *slaves, *rm;
+    pa_sink *master_sink = NULL;
+    int resample_method = PA_RESAMPLER_TRIVIAL;
+    pa_sample_spec ss;
+    pa_channel_map map;
+    struct output *o;
+    uint32_t idx;
+
+    pa_assert(m);
+
+    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
+        pa_log("failed to parse module arguments");
+        goto fail;
+    }
+
+    if ((rm = pa_modargs_get_value(ma, "resample_method", NULL))) {
+        if ((resample_method = pa_parse_resample_method(rm)) < 0) {
+            pa_log("invalid resample method '%s'", rm);
+            goto fail;
+        }
+    }
+
+    u = pa_xnew(struct userdata, 1);
+    u->core = m->core;
+    u->module = m;
+    m->userdata = u;
+    u->sink = NULL;
+    u->master = NULL;
+    u->time_event = NULL;
+    u->adjust_time = DEFAULT_ADJUST_TIME;
+    pa_thread_mq_init(&u->thread_mq, m->core->mainloop);
+    u->rtpoll = pa_rtpoll_new();
+    u->thread = NULL;
+    u->resample_method = resample_method;
+    u->outputs = pa_idxset_new(NULL, NULL);
+    memset(&u->adjust_timestamp, 0, sizeof(u->adjust_timestamp));
+    u->sink_new_slot = u->sink_unlink_slot = u->sink_state_changed_slot = NULL;
+    PA_LLIST_HEAD_INIT(struct output, u->thread_info.active_outputs);
+    pa_atomic_store(&u->thread_info.running, FALSE);
+    u->thread_info.in_null_mode = FALSE;
+    pa_rtpoll_item_new_asyncmsgq(u->rtpoll, PA_RTPOLL_EARLY, u->thread_mq.inq);
+
+    if (pa_modargs_get_value_u32(ma, "adjust_time", &u->adjust_time) < 0) {
+        pa_log("Failed to parse adjust_time value");
+        goto fail;
+    }
+
+    master_name = pa_modargs_get_value(ma, "master", NULL);
+    slaves = pa_modargs_get_value(ma, "slaves", NULL);
+    if (!master_name != !slaves) {
+        pa_log("No master or slave sinks specified");
+        goto fail;
+    }
+
+    if (master_name) {
+        if (!(master_sink = pa_namereg_get(m->core, master_name, PA_NAMEREG_SINK, 1))) {
+            pa_log("Invalid master sink '%s'", master_name);
+            goto fail;
+        }
+
+        ss = master_sink->sample_spec;
+        u->automatic = FALSE;
+    } else {
+        master_sink = NULL;
+        ss = m->core->default_sample_spec;
+        u->automatic = TRUE;
+    }
+
+    if ((pa_modargs_get_sample_spec(ma, &ss) < 0)) {
+        pa_log("Invalid sample specification.");
+        goto fail;
+    }
+
+    if (master_sink && ss.channels == master_sink->sample_spec.channels)
+        map = master_sink->channel_map;
+    else {
+        pa_assert_se(pa_channel_map_init_auto(&map, ss.channels, PA_CHANNEL_MAP_AUX));
+        pa_channel_map_init_auto(&map, ss.channels, PA_CHANNEL_MAP_DEFAULT);
+    }
+
+    if ((pa_modargs_get_channel_map(ma, NULL, &map) < 0)) {
+        pa_log("Invalid channel map.");
+        goto fail;
+    }
+
+    if (ss.channels != map.channels) {
+        pa_log("Channel map and sample specification don't match.");
+        goto fail;
+    }
+
+    if (!(u->sink = pa_sink_new(m->core, __FILE__, pa_modargs_get_value(ma, "sink_name", DEFAULT_SINK_NAME), 0, &ss, &map))) {
+        pa_log("Failed to create sink");
+        goto fail;
+    }
+
+    u->sink->parent.process_msg = sink_process_msg;
+    u->sink->get_latency = sink_get_latency_cb;
+    u->sink->set_state = sink_set_state;
+    u->sink->userdata = u;
+
+    u->sink->flags = PA_SINK_LATENCY;
+    pa_sink_set_module(u->sink, m);
+    pa_sink_set_description(u->sink, "Simultaneous output");
+    pa_sink_set_rtpoll(u->sink, u->rtpoll);
+    pa_sink_set_asyncmsgq(u->sink, u->thread_mq.inq);
+
+    u->block_size = pa_bytes_per_second(&ss) / 20; /* 50 ms */
+    if (u->block_size <= 0)
+        u->block_size = pa_frame_size(&ss);
+
+    if (!u->automatic) {
+        const char*split_state;
+        char *n = NULL;
+        pa_assert(slaves);
+
+        /* The master and slaves have been specified manually */
+
+        if (!(u->master = output_new(u, master_sink))) {
+            pa_log("Failed to create master sink input on sink '%s'.", master_sink->name);
+            goto fail;
+        }
+
+        split_state = NULL;
+        while ((n = pa_split(slaves, ",", &split_state))) {
+            pa_sink *slave_sink;
+
+            if (!(slave_sink = pa_namereg_get(m->core, n, PA_NAMEREG_SINK, 1)) || slave_sink == u->sink) {
+                pa_log("Invalid slave sink '%s'", n);
+                pa_xfree(n);
+                goto fail;
+            }
+
+            pa_xfree(n);
+
+            if (!output_new(u, slave_sink)) {
+                pa_log("Failed to create slave sink input on sink '%s'.", slave_sink->name);
+                goto fail;
+            }
+        }
+
+        if (pa_idxset_size(u->outputs) <= 1)
+            pa_log_warn("No slave sinks specified.");
+
+        u->sink_new_slot = NULL;
+
+    } else {
+        pa_sink *s;
+
+        /* We're in automatic mode, we elect one hw sink to the master
+         * and attach all other hw sinks as slaves to it */
+
+        for (s = pa_idxset_first(m->core->sinks, &idx); s; s = pa_idxset_next(m->core->sinks, &idx)) {
+
+            if (!(s->flags & PA_SINK_HARDWARE) || s == u->sink)
+                continue;
+
+            if (!output_new(u, s)) {
+                pa_log("Failed to create sink input on sink '%s'.", s->name);
+                goto fail;
+            }
+        }
+
+        u->sink_new_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_NEW_POST], (pa_hook_cb_t) sink_new_hook_cb, u);
+    }
+
+    u->sink_unlink_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_UNLINK], (pa_hook_cb_t) sink_unlink_hook_cb, u);
+    u->sink_state_changed_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_STATE_CHANGED], (pa_hook_cb_t) sink_state_changed_hook_cb, u);
+
+    pick_master(u, NULL);
+
+    if (!(u->thread = pa_thread_new(thread_func, u))) {
+        pa_log("Failed to create thread.");
+        goto fail;
+    }
+
+    /* Activate the sink and the sink inputs */
+    pa_sink_put(u->sink);
+
+    for (o = pa_idxset_first(u->outputs, &idx); o; o = pa_idxset_next(u->outputs, &idx))
+        if (o->sink_input)
+            pa_sink_input_put(o->sink_input);
+
+    if (u->adjust_time > 0) {
+        struct timeval tv;
+        pa_gettimeofday(&tv);
+        tv.tv_sec += u->adjust_time;
+        u->time_event = m->core->mainloop->time_new(m->core->mainloop, &tv, time_callback, u);
+    }
+
+    pa_modargs_free(ma);
+
+    return 0;
+
+fail:
+
+    if (ma)
+        pa_modargs_free(ma);
+
+    pa__done(m);
+
+    return -1;
+}
+
+static void output_free(struct output *o) {
+    pa_assert(o);
+
+    pick_master(o->userdata, o);
+
+    disable_output(o);
+
+    pa_assert_se(pa_idxset_remove_by_data(o->userdata->outputs, o, NULL));
+
+    update_description(o->userdata);
+
+    if (o->inq_rtpoll_item)
+        pa_rtpoll_item_free(o->inq_rtpoll_item);
+
+    if (o->outq_rtpoll_item)
+        pa_rtpoll_item_free(o->outq_rtpoll_item);
+
+    if (o->inq)
+        pa_asyncmsgq_unref(o->inq);
+
+    if (o->outq)
+        pa_asyncmsgq_unref(o->outq);
+
+    if (o->memblockq)
+        pa_memblockq_free(o->memblockq);
+
+    pa_xfree(o);
+}
+
+void pa__done(pa_module*m) {
+    struct userdata *u;
+    struct output *o;
+
+    pa_assert(m);
+
+    if (!(u = m->userdata))
+        return;
+
+    if (u->sink_new_slot)
+        pa_hook_slot_free(u->sink_new_slot);
+
+    if (u->sink_unlink_slot)
+        pa_hook_slot_free(u->sink_unlink_slot);
+
+    if (u->sink_state_changed_slot)
+        pa_hook_slot_free(u->sink_state_changed_slot);
+
+    if (u->outputs) {
+        while ((o = pa_idxset_first(u->outputs, NULL)))
+            output_free(o);
+
+        pa_idxset_free(u->outputs, NULL, NULL);
+    }
+
+    if (u->sink)
+        pa_sink_unlink(u->sink);
+
+    if (u->thread) {
+        pa_asyncmsgq_send(u->thread_mq.inq, NULL, PA_MESSAGE_SHUTDOWN, NULL, 0, NULL);
+        pa_thread_free(u->thread);
+    }
+
+    pa_thread_mq_done(&u->thread_mq);
+
+    if (u->sink)
+        pa_sink_unref(u->sink);
+
+    if (u->rtpoll)
+        pa_rtpoll_free(u->rtpoll);
+
+    if (u->time_event)
+        u->core->mainloop->time_free(u->time_event);
+
+    pa_xfree(u);
+}