loopback: add loopback module for direct connections of sinks and sources

2 files changed, 714 insertions, 3 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 561891ed..e65662c7 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1010,8 +1010,8 @@ modlibexec_LTLIBRARIES += \
 		module-tunnel-source.la \
 		module-position-event-sounds.la \
 		module-augment-properties.la \
-		module-cork-music-on-phone.la
-
+		module-cork-music-on-phone.la \
+		module-loopback.la
 
 # See comment at librtp.la above
 if !OS_IS_WIN32
@@ -1249,7 +1249,8 @@ SYMDEF_FILES = \
 		modules/module-position-event-sounds-symdef.h \
 		modules/module-augment-properties-symdef.h \
 		modules/module-cork-music-on-phone-symdef.h \
-		modules/module-console-kit-symdef.h
+		modules/module-console-kit-symdef.h \
+		modules/module-loopback-symdef.h
 
 EXTRA_DIST += $(SYMDEF_FILES)
 BUILT_SOURCES += $(SYMDEF_FILES)
@@ -1391,6 +1392,10 @@ module_tunnel_source_la_SOURCES = modules/module-tunnel.c
 module_tunnel_source_la_LDFLAGS = $(MODULE_LDFLAGS)
 module_tunnel_source_la_LIBADD = $(AM_LIBADD) libpulsecore-@PA_MAJORMINORMICRO@.la libpulsecommon-@PA_MAJORMINORMICRO@.la libpulse.la
 
+module_loopback_la_SOURCES = modules/module-loopback.c
+module_loopback_la_LDFLAGS = $(MODULE_LDFLAGS)
+module_loopback_la_LIBADD = $(AM_LIBADD) libpulsecore-@PA_MAJORMINORMICRO@.la libpulsecommon-@PA_MAJORMINORMICRO@.la libpulse.la
+
 # X11
 
 module_x11_bell_la_SOURCES = modules/x11/module-x11-bell.c
diff --git a/src/modules/module-loopback.c b/src/modules/module-loopback.c
new file mode 100644
index 00000000..8b22fa1a
--- /dev/null
+++ b/src/modules/module-loopback.c
@@ -0,0 +1,706 @@
+/***
+    This file is part of PulseAudio.
+
+    Copyright 2009 Intel Corporation
+    Contributor: Pierre-Louis Bossart <pierre-louis.bossart@intel.com>
+
+    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 2.1 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 <math.h>
+
+#include <pulse/xmalloc.h>
+
+#include <pulsecore/sink-input.h>
+#include <pulsecore/module.h>
+#include <pulsecore/modargs.h>
+#include <pulsecore/namereg.h>
+#include <pulsecore/log.h>
+#include <pulsecore/core-util.h>
+
+#include <pulse/rtclock.h>
+#include <pulse/timeval.h>
+
+#include "module-loopback-symdef.h"
+
+PA_MODULE_AUTHOR("Pierre-Louis Bossart");
+PA_MODULE_DESCRIPTION("Loopback from source to sink");
+PA_MODULE_VERSION(PACKAGE_VERSION);
+PA_MODULE_LOAD_ONCE(FALSE);
+PA_MODULE_USAGE(
+        "source=<source to connect to> "
+        "sink=<sink to connect to> "
+        "adjust_time=<how often to readjust rates in s> "
+        "latency_msec=<latency in ms> "
+        "format=<sample format> "
+        "rate=<sample rate> "
+        "channels=<number of channels> "
+        "channel_map=<channel map>");
+
+#define DEFAULT_LATENCY_MSEC 200
+
+#define MEMBLOCKQ_MAXLENGTH (1024*1024*16)
+
+#define DEFAULT_ADJUST_TIME_USEC (10*PA_USEC_PER_SEC)
+
+struct userdata {
+    pa_core *core;
+    pa_module *module;
+
+    pa_sink_input *sink_input;
+    pa_source_output *source_output;
+
+    pa_asyncmsgq *asyncmsgq;
+    pa_memblockq *memblockq;
+
+    pa_rtpoll_item *rtpoll_item_read, *rtpoll_item_write;
+
+    pa_time_event *time_event;
+    pa_usec_t adjust_time;
+
+    int64_t recv_counter;
+    int64_t send_counter;
+
+    size_t skip;
+    pa_usec_t latency;
+
+    pa_bool_t in_pop;
+    size_t min_memblockq_length;
+
+    struct {
+        int64_t send_counter;
+        size_t source_output_buffer;
+        pa_usec_t source_latency;
+
+        int64_t recv_counter;
+        size_t sink_input_buffer;
+        pa_usec_t sink_latency;
+
+        size_t min_memblockq_length;
+        size_t max_request;
+    } latency_snapshot;
+};
+
+static const char* const valid_modargs[] = {
+    "source",
+    "sink",
+    "latency",
+    "format",
+    "rate",
+    "channels",
+    "channel_map",
+    NULL,
+};
+
+enum {
+    SINK_INPUT_MESSAGE_POST = PA_SINK_INPUT_MESSAGE_MAX,
+    SINK_INPUT_MESSAGE_REWIND,
+    SINK_INPUT_MESSAGE_LATENCY_SNAPSHOT,
+    SINK_INPUT_MESSAGE_MAX_REQUEST_CHANGED
+};
+
+enum {
+    SOURCE_OUTPUT_MESSAGE_LATENCY_SNAPSHOT
+};
+
+/* Called from main context */
+static void teardown(struct userdata *u) {
+    pa_assert(u);
+    pa_assert_ctl_context();
+
+    if (u->sink_input)
+        pa_sink_input_unlink(u->sink_input);
+
+    if (u->source_output)
+        pa_source_output_unlink(u->source_output);
+
+    if (u->sink_input) {
+        pa_sink_input_unref(u->sink_input);
+        u->sink_input = NULL;
+    }
+
+    if (u->source_output) {
+        pa_source_output_unref(u->source_output);
+        u->source_output = NULL;
+    }
+}
+
+/* Called from main context */
+static void adjust_rates(struct userdata *u) {
+    size_t buffer, fs;
+    uint32_t old_rate, base_rate, new_rate;
+    pa_usec_t buffer_latency;
+
+    pa_assert(u);
+    pa_assert_ctl_context();
+
+    pa_asyncmsgq_send(u->source_output->source->asyncmsgq, PA_MSGOBJECT(u->source_output), SOURCE_OUTPUT_MESSAGE_LATENCY_SNAPSHOT, NULL, 0, NULL);
+    pa_asyncmsgq_send(u->sink_input->sink->asyncmsgq, PA_MSGOBJECT(u->sink_input), SINK_INPUT_MESSAGE_LATENCY_SNAPSHOT, NULL, 0, NULL);
+
+    buffer =
+        u->latency_snapshot.sink_input_buffer +
+        u->latency_snapshot.source_output_buffer;
+
+    if (u->latency_snapshot.recv_counter <= u->latency_snapshot.send_counter)
+        buffer += (size_t) (u->latency_snapshot.send_counter - u->latency_snapshot.recv_counter);
+    else
+        buffer += PA_CLIP_SUB(buffer, (size_t) (u->latency_snapshot.recv_counter - u->latency_snapshot.send_counter));
+
+    buffer_latency = pa_bytes_to_usec(buffer, &u->sink_input->sample_spec);
+
+    pa_log_info("Loopback overall latency is %0.2f ms + %0.2f ms + %0.2f ms = %0.2f ms",
+                (double) u->latency_snapshot.sink_latency / PA_USEC_PER_MSEC,
+                (double) buffer_latency / PA_USEC_PER_MSEC,
+                (double) u->latency_snapshot.source_latency / PA_USEC_PER_MSEC,
+                ((double) u->latency_snapshot.sink_latency + buffer_latency + u->latency_snapshot.source_latency) / PA_USEC_PER_MSEC);
+
+    pa_log_info("Should buffer %lu bytes, buffered at minimum %lu bytes",
+                u->latency_snapshot.max_request*2,
+                u->latency_snapshot.min_memblockq_length);
+
+    fs = pa_frame_size(&u->sink_input->sample_spec);
+    old_rate = u->sink_input->sample_spec.rate;
+    base_rate = u->source_output->sample_spec.rate;
+
+    if (u->latency_snapshot.min_memblockq_length < u->latency_snapshot.max_request*2)
+        new_rate = base_rate - (((u->latency_snapshot.max_request*2 - u->latency_snapshot.min_memblockq_length) / fs) *PA_USEC_PER_SEC)/u->adjust_time;
+    else
+        new_rate = base_rate + (((u->latency_snapshot.min_memblockq_length - u->latency_snapshot.max_request*2) / fs) *PA_USEC_PER_SEC)/u->adjust_time;
+
+    pa_log_info("Old rate %lu Hz, new rate %lu Hz", (unsigned long) old_rate, (unsigned long) new_rate);
+
+    pa_sink_input_set_rate(u->sink_input, new_rate);
+
+    pa_core_rttime_restart(u->core, u->time_event, pa_rtclock_now() + u->adjust_time);
+}
+
+/* Called from main context */
+static void time_callback(pa_mainloop_api *a, pa_time_event *e, const struct timeval *t, void *userdata) {
+    struct userdata *u = userdata;
+
+    pa_assert(u);
+    pa_assert(a);
+    pa_assert(u->time_event == e);
+
+    adjust_rates(u);
+}
+
+/* Called from input thread context */
+static void source_output_push_cb(pa_source_output *o, const pa_memchunk *chunk) {
+    struct userdata *u;
+    pa_memchunk copy;
+
+    pa_source_output_assert_ref(o);
+    pa_source_output_assert_io_context(o);
+    pa_assert_se(u = o->userdata);
+
+    if (u->skip > chunk->length) {
+        u->skip -= chunk->length;
+        return;
+    }
+
+    if (u->skip > 0) {
+        copy = *chunk;
+        copy.index += u->skip;
+        copy.length -= u->skip;
+        u->skip = 0;
+
+        chunk = &copy;
+    }
+
+    pa_asyncmsgq_post(u->asyncmsgq, PA_MSGOBJECT(u->sink_input), SINK_INPUT_MESSAGE_POST, NULL, 0, chunk, NULL);
+    u->send_counter += (int64_t) chunk->length;
+}
+
+/* Called from input thread context */
+static void source_output_process_rewind_cb(pa_source_output *o, size_t nbytes) {
+    struct userdata *u;
+
+    pa_source_output_assert_ref(o);
+    pa_source_output_assert_io_context(o);
+    pa_assert_se(u = o->userdata);
+
+    pa_asyncmsgq_post(u->asyncmsgq, PA_MSGOBJECT(u->sink_input), SINK_INPUT_MESSAGE_REWIND, NULL, (int64_t) nbytes, NULL, NULL);
+    u->send_counter -= (int64_t) nbytes;
+}
+
+/* Called from output thread context */
+static int source_output_process_msg_cb(pa_msgobject *obj, int code, void *data, int64_t offset, pa_memchunk *chunk) {
+    struct userdata *u = PA_SOURCE_OUTPUT(obj)->userdata;
+
+    switch (code) {
+
+        case SOURCE_OUTPUT_MESSAGE_LATENCY_SNAPSHOT: {
+            size_t length;
+
+            length = pa_memblockq_get_length(u->source_output->thread_info.delay_memblockq);
+
+            u->latency_snapshot.send_counter = u->send_counter;
+            u->latency_snapshot.source_output_buffer = u->source_output->thread_info.resampler ? pa_resampler_result(u->source_output->thread_info.resampler, length) : length;
+            u->latency_snapshot.source_latency = pa_source_get_latency_within_thread(u->source_output->source);
+
+            return 0;
+        }
+    }
+
+    return pa_source_output_process_msg(obj, code, data, offset, chunk);
+}
+
+/* Called from output thread context */
+static void source_output_attach_cb(pa_source_output *o) {
+    struct userdata *u;
+
+    pa_source_output_assert_ref(o);
+    pa_source_output_assert_io_context(o);
+    pa_assert_se(u = o->userdata);
+
+    u->rtpoll_item_write = pa_rtpoll_item_new_asyncmsgq_write(
+            o->source->thread_info.rtpoll,
+            PA_RTPOLL_LATE,
+            u->asyncmsgq);
+}
+
+/* Called from output thread context */
+static void source_output_detach_cb(pa_source_output *o) {
+    struct userdata *u;
+
+    pa_source_output_assert_ref(o);
+    pa_source_output_assert_io_context(o);
+    pa_assert_se(u = o->userdata);
+
+    if (u->rtpoll_item_write) {
+        pa_rtpoll_item_free(u->rtpoll_item_write);
+        u->rtpoll_item_write = NULL;
+    }
+}
+
+/* Called from output thread context */
+static void source_output_state_change_cb(pa_source_output *o, pa_source_output_state_t state) {
+    struct userdata *u;
+
+    pa_source_output_assert_ref(o);
+    pa_source_output_assert_io_context(o);
+    pa_assert_se(u = o->userdata);
+
+    if (PA_SOURCE_OUTPUT_IS_LINKED(state) && o->thread_info.state == PA_SOURCE_OUTPUT_INIT) {
+
+        u->skip = pa_usec_to_bytes(PA_CLIP_SUB(pa_source_get_latency_within_thread(o->source),
+                                               u->latency),
+                                   &o->sample_spec);
+
+        pa_log_info("Skipping %lu bytes", (unsigned long) u->skip);
+    }
+}
+
+/* Called from main thread */
+static void source_output_kill_cb(pa_source_output *o) {
+    struct userdata *u;
+
+    pa_source_output_assert_ref(o);
+    pa_assert_ctl_context();
+    pa_assert_se(u = o->userdata);
+
+    teardown(u);
+    pa_module_unload_request(u->module, TRUE);
+}
+
+/* Called from output thread context */
+static void update_min_memblockq_length(struct userdata *u) {
+    size_t length;
+
+    pa_assert(u);
+    pa_sink_input_assert_io_context(u->sink_input);
+
+    length = pa_memblockq_get_length(u->memblockq);
+
+    if (u->min_memblockq_length == (size_t) -1 ||
+        length < u->min_memblockq_length)
+        u->min_memblockq_length = length;
+}
+
+/* Called from output thread context */
+static int sink_input_pop_cb(pa_sink_input *i, size_t nbytes, pa_memchunk *chunk) {
+    struct userdata *u;
+
+    pa_sink_input_assert_ref(i);
+    pa_sink_input_assert_io_context(i);
+    pa_assert_se(u = i->userdata);
+    pa_assert(chunk);
+
+    u->in_pop = TRUE;
+    while (pa_asyncmsgq_process_one(u->asyncmsgq) > 0)
+        ;
+    u->in_pop = FALSE;
+
+    if (pa_memblockq_peek(u->memblockq, chunk) < 0) {
+        pa_log_info("Coud not peek into queue");
+        return -1;
+    }
+
+    chunk->length = PA_MIN(chunk->length, nbytes);
+    pa_memblockq_drop(u->memblockq, chunk->length);
+
+    update_min_memblockq_length(u);
+
+    return 0;
+}
+
+/* Called from output thread context */
+static void sink_input_process_rewind_cb(pa_sink_input *i, size_t nbytes) {
+    struct userdata *u;
+
+    pa_sink_input_assert_ref(i);
+    pa_sink_input_assert_io_context(i);
+    pa_assert_se(u = i->userdata);
+
+    pa_memblockq_rewind(u->memblockq, nbytes);
+}
+
+/* Called from output thread context */
+static int sink_input_process_msg_cb(pa_msgobject *obj, int code, void *data, int64_t offset, pa_memchunk *chunk) {
+    struct userdata *u = PA_SINK_INPUT(obj)->userdata;
+
+    switch (code) {
+
+        case PA_SINK_INPUT_MESSAGE_GET_LATENCY: {
+             pa_usec_t *r = data;
+
+             pa_sink_input_assert_io_context(u->sink_input);
+
+            *r = pa_bytes_to_usec(pa_memblockq_get_length(u->memblockq), &u->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:
+
+            pa_sink_input_assert_io_context(u->sink_input);
+
+            if (PA_SINK_IS_OPENED(u->sink_input->sink->thread_info.state))
+                pa_memblockq_push_align(u->memblockq, chunk);
+            else
+                pa_memblockq_flush_write(u->memblockq);
+
+            update_min_memblockq_length(u);
+
+            /* Is this the end of an underrun? Then let's start things
+             * right-away */
+            if (!u->in_pop &&
+                u->sink_input->thread_info.underrun_for > 0 &&
+                pa_memblockq_is_readable(u->memblockq)) {
+
+                pa_log_debug("Requesting rewind due to end of underrun.");
+                pa_sink_input_request_rewind(u->sink_input,
+                                             (size_t) (u->sink_input->thread_info.underrun_for == (size_t) -1 ? 0 : u->sink_input->thread_info.underrun_for),
+                                             FALSE, TRUE, FALSE);
+            }
+
+            u->recv_counter += (int64_t) chunk->length;
+
+            return 0;
+
+        case SINK_INPUT_MESSAGE_REWIND:
+
+            pa_sink_input_assert_io_context(u->sink_input);
+
+            if (PA_SINK_IS_OPENED(u->sink_input->sink->thread_info.state))
+                pa_memblockq_seek(u->memblockq, -offset, PA_SEEK_RELATIVE, TRUE);
+            else
+                pa_memblockq_flush_write(u->memblockq);
+
+            u->recv_counter -= offset;
+
+            update_min_memblockq_length(u);
+
+            return 0;
+
+        case SINK_INPUT_MESSAGE_LATENCY_SNAPSHOT: {
+            size_t length;
+
+            update_min_memblockq_length(u);
+
+            length = pa_memblockq_get_length(u->sink_input->thread_info.render_memblockq);
+
+            u->latency_snapshot.recv_counter = u->recv_counter;
+            u->latency_snapshot.sink_input_buffer =
+                pa_memblockq_get_length(u->memblockq) +
+                (u->sink_input->thread_info.resampler ? pa_resampler_request(u->sink_input->thread_info.resampler, length) : length);
+            u->latency_snapshot.sink_latency = pa_sink_get_latency_within_thread(u->sink_input->sink);
+
+            u->latency_snapshot.max_request = pa_sink_input_get_max_request(u->sink_input);
+
+            u->latency_snapshot.min_memblockq_length = u->min_memblockq_length;
+            u->min_memblockq_length = (size_t) -1;
+
+            return 0;
+        }
+
+        case SINK_INPUT_MESSAGE_MAX_REQUEST_CHANGED: {
+            /* This message is sent from the IO thread to the main
+             * thread! So don't be confused. All the user cases above
+             * are executed in thread context, but this one is not! */
+
+            pa_assert_ctl_context();
+
+            adjust_rates(u);
+            return 0;
+        }
+    }
+
+    return pa_sink_input_process_msg(obj, code, data, offset, chunk);
+}
+
+/* Called from output thread context */
+static void sink_input_attach_cb(pa_sink_input *i) {
+    struct userdata *u;
+
+    pa_sink_input_assert_ref(i);
+    pa_sink_input_assert_io_context(i);
+    pa_assert_se(u = i->userdata);
+
+    u->rtpoll_item_read = pa_rtpoll_item_new_asyncmsgq_read(
+            i->sink->thread_info.rtpoll,
+            PA_RTPOLL_LATE,
+            u->asyncmsgq);
+
+    pa_memblockq_set_prebuf(u->memblockq, pa_sink_input_get_max_request(i)*2);
+    pa_memblockq_set_maxrewind(u->memblockq, pa_sink_input_get_max_rewind(i));
+
+    u->min_memblockq_length = (size_t) -1;
+}
+
+/* Called from output thread context */
+static void sink_input_detach_cb(pa_sink_input *i) {
+    struct userdata *u;
+
+    pa_sink_input_assert_ref(i);
+    pa_sink_input_assert_io_context(i);
+    pa_assert_se(u = i->userdata);
+
+    if (u->rtpoll_item_read) {
+        pa_rtpoll_item_free(u->rtpoll_item_read);
+        u->rtpoll_item_read = NULL;
+    }
+}
+
+/* Called from output thread context */
+static void sink_input_update_max_rewind_cb(pa_sink_input *i, size_t nbytes) {
+    struct userdata *u;
+
+    pa_sink_input_assert_ref(i);
+    pa_sink_input_assert_io_context(i);
+    pa_assert_se(u = i->userdata);
+
+    pa_memblockq_set_maxrewind(u->memblockq, nbytes);
+}
+
+/* Called from output thread context */
+static void sink_input_update_max_request_cb(pa_sink_input *i, size_t nbytes) {
+    struct userdata *u;
+
+    pa_sink_input_assert_ref(i);
+    pa_sink_input_assert_io_context(i);
+    pa_assert_se(u = i->userdata);
+
+    pa_memblockq_set_prebuf(u->memblockq, nbytes*2);
+    pa_log_info("Max request changed");
+    pa_asyncmsgq_post(pa_thread_mq_get()->outq, PA_MSGOBJECT(u->sink_input), SINK_INPUT_MESSAGE_MAX_REQUEST_CHANGED, NULL, 0, NULL, NULL);
+}
+
+/* Called from main thread */
+static void sink_input_kill_cb(pa_sink_input *i) {
+    struct userdata *u;
+
+    pa_sink_input_assert_ref(i);
+    pa_assert_ctl_context();
+    pa_assert_se(u = i->userdata);
+
+    teardown(u);
+    pa_module_unload_request(u->module, TRUE);
+}
+
+int pa__init(pa_module *m) {
+    pa_modargs *ma = NULL;
+    struct userdata *u;
+    pa_sink *sink;
+    pa_sink_input_new_data sink_input_data;
+    pa_source *source;
+    pa_source_output_new_data source_output_data;
+    uint32_t latency_msec;
+    pa_sample_spec ss;
+    pa_channel_map map;
+    pa_memchunk silence;
+    uint32_t adjust_time_sec;
+
+    pa_assert(m);
+
+    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
+        pa_log("Failed to parse module arguments");
+        goto fail;
+    }
+
+    if (!(source = pa_namereg_get(m->core, pa_modargs_get_value(ma, "source", NULL), PA_NAMEREG_SOURCE))) {
+        pa_log("No such source.");
+        goto fail;
+    }
+
+    if (!(sink = pa_namereg_get(m->core, pa_modargs_get_value(ma, "sink", NULL), PA_NAMEREG_SINK))) {
+        pa_log("No such sink.");
+        goto fail;
+    }
+
+    ss = sink->sample_spec;
+    map = sink->channel_map;
+    if (pa_modargs_get_sample_spec_and_channel_map(ma, &ss, &map, PA_CHANNEL_MAP_DEFAULT) < 0) {
+        pa_log("Invalid sample format specification or channel map");
+        goto fail;
+    }
+
+    latency_msec = DEFAULT_LATENCY_MSEC;
+    if (pa_modargs_get_value_u32(ma, "latency_msec", &latency_msec) < 0 || latency_msec < 1 || latency_msec > 2000) {
+        pa_log("Invalid latency specification");
+        goto fail;
+    }
+
+    m->userdata = u = pa_xnew0(struct userdata, 1);
+    u->core = m->core;
+    u->module = m;
+    u->latency = (pa_usec_t) latency_msec * PA_USEC_PER_MSEC;
+
+    adjust_time_sec = DEFAULT_ADJUST_TIME_USEC / PA_USEC_PER_SEC;
+    if (pa_modargs_get_value_u32(ma, "adjust_time", &adjust_time_sec) < 0) {
+        pa_log("Failed to parse adjust_time value");
+        goto fail;
+    }
+
+    if (adjust_time_sec != DEFAULT_ADJUST_TIME_USEC / PA_USEC_PER_SEC)
+        u->adjust_time = adjust_time_sec * PA_USEC_PER_SEC;
+    else
+        u->adjust_time = DEFAULT_ADJUST_TIME_USEC;
+
+    pa_sink_input_new_data_init(&sink_input_data);
+    sink_input_data.driver = __FILE__;
+    sink_input_data.module = m;
+    sink_input_data.sink = sink;
+    pa_proplist_setf(sink_input_data.proplist, PA_PROP_MEDIA_NAME, "Loopback of %s", pa_proplist_gets(source->proplist, PA_PROP_DEVICE_DESCRIPTION));
+    pa_proplist_sets(sink_input_data.proplist, PA_PROP_MEDIA_ROLE, "abstract");
+    pa_sink_input_new_data_set_sample_spec(&sink_input_data, &ss);
+    pa_sink_input_new_data_set_channel_map(&sink_input_data, &map);
+
+    pa_sink_input_new(&u->sink_input, m->core, &sink_input_data, PA_SINK_INPUT_VARIABLE_RATE);
+    pa_sink_input_new_data_done(&sink_input_data);
+
+    if (!u->sink_input)
+        goto fail;
+
+    u->sink_input->parent.process_msg = sink_input_process_msg_cb;
+    u->sink_input->pop = sink_input_pop_cb;
+    u->sink_input->process_rewind = sink_input_process_rewind_cb;
+    u->sink_input->kill = sink_input_kill_cb;
+    u->sink_input->attach = sink_input_attach_cb;
+    u->sink_input->detach = sink_input_detach_cb;
+    u->sink_input->update_max_rewind = sink_input_update_max_rewind_cb;
+    u->sink_input->update_max_request = sink_input_update_max_request_cb;
+    u->sink_input->userdata = u;
+
+    pa_sink_input_set_requested_latency(u->sink_input, u->latency/3);
+
+    pa_source_output_new_data_init(&source_output_data);
+    source_output_data.driver = __FILE__;
+    source_output_data.module = m;
+    source_output_data.source = source;
+    pa_proplist_setf(source_output_data.proplist, PA_PROP_MEDIA_NAME, "Loopback to %s", pa_proplist_gets(sink->proplist, PA_PROP_DEVICE_DESCRIPTION));
+    pa_proplist_sets(source_output_data.proplist, PA_PROP_MEDIA_ROLE, "abstract");
+    pa_source_output_new_data_set_sample_spec(&source_output_data, &ss);
+    pa_sink_input_new_data_set_channel_map(&sink_input_data, &map);
+
+    pa_source_output_new(&u->source_output, m->core, &source_output_data, 0);
+    pa_source_output_new_data_done(&source_output_data);
+
+    if (!u->source_output)
+        goto fail;
+
+    u->source_output->parent.process_msg = source_output_process_msg_cb;
+    u->source_output->push = source_output_push_cb;
+    u->source_output->process_rewind = source_output_process_rewind_cb;
+    u->source_output->kill = source_output_kill_cb;
+    u->source_output->attach = source_output_attach_cb;
+    u->source_output->detach = source_output_detach_cb;
+    u->source_output->state_change = source_output_state_change_cb;
+    u->source_output->userdata = u;
+
+    pa_source_output_set_requested_latency(u->source_output, u->latency/3);
+
+    pa_sink_input_get_silence(u->sink_input, &silence);
+    u->memblockq = pa_memblockq_new(
+            0,                      /* idx */
+            MEMBLOCKQ_MAXLENGTH,    /* maxlength */
+            MEMBLOCKQ_MAXLENGTH,    /* tlength */
+            pa_frame_size(&ss),     /* base */
+            0,                      /* prebuf */
+            0,                      /* minreq */
+            0,                      /* maxrewind */
+            &silence);              /* silence frame */
+    pa_memblock_unref(silence.memblock);
+
+    u->asyncmsgq = pa_asyncmsgq_new(0);
+
+    pa_sink_input_put(u->sink_input);
+    pa_source_output_put(u->source_output);
+
+    if (u->adjust_time > 0)
+        u->time_event = pa_core_rttime_new(m->core, pa_rtclock_now() + u->adjust_time, time_callback, u);
+
+    pa_modargs_free(ma);
+    return 0;
+
+fail:
+    if (ma)
+        pa_modargs_free(ma);
+
+    pa__done(m);
+
+    return -1;
+}
+
+void pa__done(pa_module*m) {
+    struct userdata *u;
+
+    pa_assert(m);
+
+    if (!(u = m->userdata))
+        return;
+
+    teardown(u);
+
+    if (u->memblockq)
+        pa_memblockq_free(u->memblockq);
+
+    if (u->asyncmsgq)
+        pa_asyncmsgq_unref(u->asyncmsgq);
+
+    if (u->time_event)
+        u->core->mainloop->time_free(u->time_event);
+
+    pa_xfree(u);
+}