int pa__init(pa_module*m) {
    struct userdata *u;
    pa_sample_spec ss;
    pa_channel_map map;
    pa_modargs *ma;
    pa_sink *master=NULL;
    pa_sink_input_new_data sink_input_data;
    pa_sink_new_data sink_data;
    pa_bool_t use_volume_sharing = TRUE;
    pa_bool_t force_flat_volume = FALSE;
    pa_memchunk silence;

    pa_assert(m);

    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
        pa_log("Failed to parse module arguments.");
        goto fail;
    }

    if (!(master = pa_namereg_get(m->core, pa_modargs_get_value(ma, "master", NULL), PA_NAMEREG_SINK))) {
        pa_log("Master sink not found");
        goto fail;
    }

    pa_assert(master);

    ss = master->sample_spec;
    ss.format = PA_SAMPLE_FLOAT32;
    map = master->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;
    }

    if (pa_modargs_get_value_boolean(ma, "use_volume_sharing", &use_volume_sharing) < 0) {
        pa_log("use_volume_sharing= expects a boolean argument");
        goto fail;
    }

    if (pa_modargs_get_value_boolean(ma, "force_flat_volume", &force_flat_volume) < 0) {
        pa_log("force_flat_volume= expects a boolean argument");
        goto fail;
    }

    if (use_volume_sharing && force_flat_volume) {
        pa_log("Flat volume can't be forced when using volume sharing.");
        goto fail;
    }

    u = pa_xnew0(struct userdata, 1);
    u->module = m;
    m->userdata = u;
    u->channels = ss.channels;

    /* Create sink */
    pa_sink_new_data_init(&sink_data);
    sink_data.driver = __FILE__;
    sink_data.module = m;
    if (!(sink_data.name = pa_xstrdup(pa_modargs_get_value(ma, "sink_name", NULL))))
        sink_data.name = pa_sprintf_malloc("%s.vsink", master->name);
    pa_sink_new_data_set_sample_spec(&sink_data, &ss);
    pa_sink_new_data_set_channel_map(&sink_data, &map);
    pa_proplist_sets(sink_data.proplist, PA_PROP_DEVICE_MASTER_DEVICE, master->name);
    pa_proplist_sets(sink_data.proplist, PA_PROP_DEVICE_CLASS, "filter");
    pa_proplist_sets(sink_data.proplist, "device.vsink.name", sink_data.name);

    if (pa_modargs_get_proplist(ma, "sink_properties", sink_data.proplist, PA_UPDATE_REPLACE) < 0) {
        pa_log("Invalid properties");
        pa_sink_new_data_done(&sink_data);
        goto fail;
    }

    if ((u->auto_desc = !pa_proplist_contains(sink_data.proplist, PA_PROP_DEVICE_DESCRIPTION))) {
        const char *z;

        z = pa_proplist_gets(master->proplist, PA_PROP_DEVICE_DESCRIPTION);
        pa_proplist_setf(sink_data.proplist, PA_PROP_DEVICE_DESCRIPTION, "Virtual Sink %s on %s", sink_data.name, z ? z : master->name);
    }

    u->sink = pa_sink_new(m->core, &sink_data, (master->flags & (PA_SINK_LATENCY|PA_SINK_DYNAMIC_LATENCY))
                                               | (use_volume_sharing ? PA_SINK_SHARE_VOLUME_WITH_MASTER : 0));
    pa_sink_new_data_done(&sink_data);

    if (!u->sink) {
        pa_log("Failed to create sink.");
        goto fail;
    }

    u->sink->parent.process_msg = sink_process_msg_cb;
    u->sink->set_state = sink_set_state_cb;
    u->sink->update_requested_latency = sink_update_requested_latency_cb;
    u->sink->request_rewind = sink_request_rewind_cb;
    pa_sink_set_set_mute_callback(u->sink, sink_set_mute_cb);
    if (!use_volume_sharing) {
        pa_sink_set_set_volume_callback(u->sink, sink_set_volume_cb);
        pa_sink_enable_decibel_volume(u->sink, TRUE);
    }
    /* Normally this flag would be enabled automatically be we can force it. */
    if (force_flat_volume)
        u->sink->flags |= PA_SINK_FLAT_VOLUME;
    u->sink->userdata = u;

    pa_sink_set_asyncmsgq(u->sink, master->asyncmsgq);

    /* Create sink input */
    pa_sink_input_new_data_init(&sink_input_data);
    sink_input_data.driver = __FILE__;
    sink_input_data.module = m;
    pa_sink_input_new_data_set_sink(&sink_input_data, master, FALSE);
    sink_input_data.origin_sink = u->sink;
    pa_proplist_setf(sink_input_data.proplist, PA_PROP_MEDIA_NAME, "Virtual Sink Stream from %s", pa_proplist_gets(u->sink->proplist, PA_PROP_DEVICE_DESCRIPTION));
    pa_proplist_sets(sink_input_data.proplist, PA_PROP_MEDIA_ROLE, "filter");
    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_new_data_done(&sink_input_data);

    if (!u->sink_input)
        goto fail;

    u->sink_input->pop = sink_input_pop_cb;
    u->sink_input->process_rewind = sink_input_process_rewind_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->update_sink_latency_range = sink_input_update_sink_latency_range_cb;
    u->sink_input->update_sink_fixed_latency = sink_input_update_sink_fixed_latency_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->state_change = sink_input_state_change_cb;
    u->sink_input->moving = sink_input_moving_cb;
    u->sink_input->volume_changed = use_volume_sharing ? NULL : sink_input_volume_changed_cb;
    u->sink_input->mute_changed = sink_input_mute_changed_cb;
    u->sink_input->userdata = u;

    u->sink->input_to_master = u->sink_input;

    pa_sink_input_get_silence(u->sink_input, &silence);
    u->memblockq = pa_memblockq_new("module-virtual-sink memblockq", 0, MEMBLOCKQ_MAXLENGTH, 0, &ss, 1, 1, 0, &silence);
    pa_memblock_unref(silence.memblock);

    /* (9) INITIALIZE ANYTHING ELSE YOU NEED HERE */

    pa_sink_put(u->sink);
    pa_sink_input_put(u->sink_input);

    pa_modargs_free(ma);

    return 0;

fail:
    if (ma)
        pa_modargs_free(ma);

    pa__done(m);

    return -1;
}
int pa__init(pa_module*m) {
    struct userdata *u;
    pa_sample_spec ss, sink_input_ss;
    pa_channel_map map, sink_input_map;
    pa_modargs *ma;
    pa_sink *master=NULL;
    pa_sink_input_new_data sink_input_data;
    pa_sink_new_data sink_data;
    bool use_volume_sharing = true;
    bool force_flat_volume = false;
    pa_memchunk silence;

    const char *hrir_file;
    unsigned i, j, found_channel_left, found_channel_right;
    float *hrir_data;

    pa_sample_spec hrir_ss;
    pa_channel_map hrir_map;

    pa_sample_spec hrir_temp_ss;
    pa_memchunk hrir_temp_chunk, hrir_temp_chunk_resampled;
    pa_resampler *resampler;

    size_t hrir_copied_length, hrir_total_length;

    hrir_temp_chunk.memblock = NULL;
    hrir_temp_chunk_resampled.memblock = NULL;

    pa_assert(m);

    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
        pa_log("Failed to parse module arguments.");
        goto fail;
    }

    if (!(master = pa_namereg_get(m->core, pa_modargs_get_value(ma, "master", NULL), PA_NAMEREG_SINK))) {
        pa_log("Master sink not found");
        goto fail;
    }

    pa_assert(master);

    u = pa_xnew0(struct userdata, 1);
    u->module = m;
    m->userdata = u;

    /* Initialize hrir and input buffer */
    /* this is the hrir file for the left ear! */
    if (!(hrir_file = pa_modargs_get_value(ma, "hrir", NULL))) {
        pa_log("The mandatory 'hrir' module argument is missing.");
        goto fail;
    }

    if (pa_sound_file_load(master->core->mempool, hrir_file, &hrir_temp_ss, &hrir_map, &hrir_temp_chunk, NULL) < 0) {
        pa_log("Cannot load hrir file.");
        goto fail;
    }

    /* sample spec / map of hrir */
    hrir_ss.format = PA_SAMPLE_FLOAT32;
    hrir_ss.rate = master->sample_spec.rate;
    hrir_ss.channels = hrir_temp_ss.channels;

    /* sample spec of sink */
    ss = hrir_ss;
    map = hrir_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;
    }
    ss.format = PA_SAMPLE_FLOAT32;
    hrir_ss.rate = ss.rate;
    u->channels = ss.channels;

    if (pa_modargs_get_value_boolean(ma, "use_volume_sharing", &use_volume_sharing) < 0) {
        pa_log("use_volume_sharing= expects a boolean argument");
        goto fail;
    }

    if (pa_modargs_get_value_boolean(ma, "force_flat_volume", &force_flat_volume) < 0) {
        pa_log("force_flat_volume= expects a boolean argument");
        goto fail;
    }

    if (use_volume_sharing && force_flat_volume) {
        pa_log("Flat volume can't be forced when using volume sharing.");
        goto fail;
    }

    /* sample spec / map of sink input */
    pa_channel_map_init_stereo(&sink_input_map);
    sink_input_ss.channels = 2;
    sink_input_ss.format = PA_SAMPLE_FLOAT32;
    sink_input_ss.rate = ss.rate;

    u->sink_fs = pa_frame_size(&ss);
    u->fs = pa_frame_size(&sink_input_ss);

    /* Create sink */
    pa_sink_new_data_init(&sink_data);
    sink_data.driver = __FILE__;
    sink_data.module = m;
    if (!(sink_data.name = pa_xstrdup(pa_modargs_get_value(ma, "sink_name", NULL))))
        sink_data.name = pa_sprintf_malloc("%s.vsurroundsink", master->name);
    pa_sink_new_data_set_sample_spec(&sink_data, &ss);
    pa_sink_new_data_set_channel_map(&sink_data, &map);
    pa_proplist_sets(sink_data.proplist, PA_PROP_DEVICE_MASTER_DEVICE, master->name);
    pa_proplist_sets(sink_data.proplist, PA_PROP_DEVICE_CLASS, "filter");
    pa_proplist_sets(sink_data.proplist, "device.vsurroundsink.name", sink_data.name);

    if (pa_modargs_get_proplist(ma, "sink_properties", sink_data.proplist, PA_UPDATE_REPLACE) < 0) {
        pa_log("Invalid properties");
        pa_sink_new_data_done(&sink_data);
        goto fail;
    }

    if ((u->auto_desc = !pa_proplist_contains(sink_data.proplist, PA_PROP_DEVICE_DESCRIPTION))) {
        const char *z;

        z = pa_proplist_gets(master->proplist, PA_PROP_DEVICE_DESCRIPTION);
        pa_proplist_setf(sink_data.proplist, PA_PROP_DEVICE_DESCRIPTION, "Virtual Surround Sink %s on %s", sink_data.name, z ? z : master->name);
    }

    u->sink = pa_sink_new(m->core, &sink_data, (master->flags & (PA_SINK_LATENCY|PA_SINK_DYNAMIC_LATENCY))
                                               | (use_volume_sharing ? PA_SINK_SHARE_VOLUME_WITH_MASTER : 0));
    pa_sink_new_data_done(&sink_data);

    if (!u->sink) {
        pa_log("Failed to create sink.");
        goto fail;
    }

    u->sink->parent.process_msg = sink_process_msg_cb;
    u->sink->set_state = sink_set_state_cb;
    u->sink->update_requested_latency = sink_update_requested_latency_cb;
    u->sink->request_rewind = sink_request_rewind_cb;
    pa_sink_set_set_mute_callback(u->sink, sink_set_mute_cb);
    if (!use_volume_sharing) {
        pa_sink_set_set_volume_callback(u->sink, sink_set_volume_cb);
        pa_sink_enable_decibel_volume(u->sink, true);
    }
    /* Normally this flag would be enabled automatically be we can force it. */
    if (force_flat_volume)
        u->sink->flags |= PA_SINK_FLAT_VOLUME;
    u->sink->userdata = u;

    pa_sink_set_asyncmsgq(u->sink, master->asyncmsgq);

    /* Create sink input */
    pa_sink_input_new_data_init(&sink_input_data);
    sink_input_data.driver = __FILE__;
    sink_input_data.module = m;
    pa_sink_input_new_data_set_sink(&sink_input_data, master, false);
    sink_input_data.origin_sink = u->sink;
    pa_proplist_setf(sink_input_data.proplist, PA_PROP_MEDIA_NAME, "Virtual Surround Sink Stream from %s", pa_proplist_gets(u->sink->proplist, PA_PROP_DEVICE_DESCRIPTION));
    pa_proplist_sets(sink_input_data.proplist, PA_PROP_MEDIA_ROLE, "filter");
    pa_sink_input_new_data_set_sample_spec(&sink_input_data, &sink_input_ss);
    pa_sink_input_new_data_set_channel_map(&sink_input_data, &sink_input_map);

    pa_sink_input_new(&u->sink_input, m->core, &sink_input_data);
    pa_sink_input_new_data_done(&sink_input_data);

    if (!u->sink_input)
        goto fail;

    u->sink_input->pop = sink_input_pop_cb;
    u->sink_input->process_rewind = sink_input_process_rewind_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->update_sink_latency_range = sink_input_update_sink_latency_range_cb;
    u->sink_input->update_sink_fixed_latency = sink_input_update_sink_fixed_latency_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->state_change = sink_input_state_change_cb;
    u->sink_input->moving = sink_input_moving_cb;
    u->sink_input->volume_changed = use_volume_sharing ? NULL : sink_input_volume_changed_cb;
    u->sink_input->mute_changed = sink_input_mute_changed_cb;
    u->sink_input->userdata = u;

    u->sink->input_to_master = u->sink_input;

    pa_sink_input_get_silence(u->sink_input, &silence);
    u->memblockq = pa_memblockq_new("module-virtual-surround-sink memblockq", 0, MEMBLOCKQ_MAXLENGTH, 0, &sink_input_ss, 1, 1, 0, &silence);
    pa_memblock_unref(silence.memblock);

    /* resample hrir */
    resampler = pa_resampler_new(u->sink->core->mempool, &hrir_temp_ss, &hrir_map, &hrir_ss, &hrir_map,
                                 PA_RESAMPLER_SRC_SINC_BEST_QUALITY, PA_RESAMPLER_NO_REMAP);

    u->hrir_samples = hrir_temp_chunk.length / pa_frame_size(&hrir_temp_ss) * hrir_ss.rate / hrir_temp_ss.rate;
    if (u->hrir_samples > 64) {
        u->hrir_samples = 64;
        pa_log("The (resampled) hrir contains more than 64 samples. Only the first 64 samples will be used to limit processor usage.");
    }

    hrir_total_length = u->hrir_samples * pa_frame_size(&hrir_ss);
    u->hrir_channels = hrir_ss.channels;

    u->hrir_data = (float *) pa_xmalloc(hrir_total_length);
    hrir_copied_length = 0;

    /* add silence to the hrir until we get enough samples out of the resampler */
    while (hrir_copied_length < hrir_total_length) {
        pa_resampler_run(resampler, &hrir_temp_chunk, &hrir_temp_chunk_resampled);
        if (hrir_temp_chunk.memblock != hrir_temp_chunk_resampled.memblock) {
            /* Silence input block */
            pa_silence_memblock(hrir_temp_chunk.memblock, &hrir_temp_ss);
        }

        if (hrir_temp_chunk_resampled.memblock) {
            /* Copy hrir data */
            hrir_data = (float *) pa_memblock_acquire(hrir_temp_chunk_resampled.memblock);

            if (hrir_total_length - hrir_copied_length >= hrir_temp_chunk_resampled.length) {
                memcpy(u->hrir_data + hrir_copied_length, hrir_data, hrir_temp_chunk_resampled.length);
                hrir_copied_length += hrir_temp_chunk_resampled.length;
            } else {
                memcpy(u->hrir_data + hrir_copied_length, hrir_data, hrir_total_length - hrir_copied_length);
                hrir_copied_length = hrir_total_length;
            }

            pa_memblock_release(hrir_temp_chunk_resampled.memblock);
            pa_memblock_unref(hrir_temp_chunk_resampled.memblock);
            hrir_temp_chunk_resampled.memblock = NULL;
        }
    }

    pa_resampler_free(resampler);

    pa_memblock_unref(hrir_temp_chunk.memblock);
    hrir_temp_chunk.memblock = NULL;

    if (hrir_map.channels < map.channels) {
        pa_log("hrir file does not have enough channels!");
        goto fail;
    }

    normalize_hrir(u);

    /* create mapping between hrir and input */
    u->mapping_left = (unsigned *) pa_xnew0(unsigned, u->channels);
    u->mapping_right = (unsigned *) pa_xnew0(unsigned, u->channels);
    for (i = 0; i < map.channels; i++) {
        found_channel_left = 0;
        found_channel_right = 0;

        for (j = 0; j < hrir_map.channels; j++) {
            if (hrir_map.map[j] == map.map[i]) {
                u->mapping_left[i] = j;
                found_channel_left = 1;
            }

            if (hrir_map.map[j] == mirror_channel(map.map[i])) {
                u->mapping_right[i] = j;
                found_channel_right = 1;
            }
        }

        if (!found_channel_left) {
            pa_log("Cannot find mapping for channel %s", pa_channel_position_to_string(map.map[i]));
            goto fail;
        }
        if (!found_channel_right) {
            pa_log("Cannot find mapping for channel %s", pa_channel_position_to_string(mirror_channel(map.map[i])));
            goto fail;
        }
    }

    u->input_buffer = pa_xmalloc0(u->hrir_samples * u->sink_fs);
    u->input_buffer_offset = 0;

    pa_sink_put(u->sink);
    pa_sink_input_put(u->sink_input);

    pa_modargs_free(ma);
    return 0;

fail:
    if (hrir_temp_chunk.memblock)
        pa_memblock_unref(hrir_temp_chunk.memblock);

    if (hrir_temp_chunk_resampled.memblock)
        pa_memblock_unref(hrir_temp_chunk_resampled.memblock);

    if (ma)
        pa_modargs_free(ma);

    pa__done(m);

    return -1;
}