PulseAudio output: rewrite

This should fix the deadlocks and memory starvation problems.

modules/audio_output/pulse.c

@@ -21,51 +21,20 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  *****************************************************************************/
 
-/*****************************************************************************
- * Preamble
- *****************************************************************************/
 #ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif
 
 #include <vlc_common.h>
 #include <vlc_plugin.h>
-
 #include <vlc_aout.h>
 #include <vlc_cpu.h>
 
 #include <pulse/pulseaudio.h>
 
-/*****************************************************************************
- * aout_sys_t: Pulseaudio output method descriptor
- *****************************************************************************
- * This structure is part of the audio output thread descriptor.
- * It describes the specific properties of an audio device.
- *****************************************************************************/
-struct aout_sys_t
-{
-    struct pa_stream *stream; /**< PulseAudio playback stream object */
-    struct pa_context *context; /**< PulseAudio connection context */
-    struct pa_threaded_mainloop *mainloop; /**< PulseAudio event loop */
-    size_t buffer_size;
-    mtime_t start_date;
-};
-
-/*****************************************************************************
- * Local prototypes
- *****************************************************************************/
 static int  Open        ( vlc_object_t * );
 static void Close       ( vlc_object_t * );
-static void Play        ( aout_instance_t * );
 
-static void context_state_cb(pa_context *c, void *userdata);
-static void stream_state_cb(pa_stream *s, void * userdata);
-static void stream_request_cb(pa_stream *s, size_t length, void *userdata);
-static void success_cb(pa_stream *s, int sucess, void *userdata);
-
-/*****************************************************************************
- * Module descriptor
- *****************************************************************************/
 vlc_module_begin ()
     set_shortname( "PulseAudio" )
     set_description( N_("Pulseaudio audio output") )
@@ -76,30 +45,221 @@ vlc_module_begin ()
     set_callbacks( Open, Close )
 vlc_module_end ()
 
+struct aout_sys_t
+{
+    pa_stream *stream; /**< PulseAudio playback stream object */
+    pa_context *context; /**< PulseAudio connection context */
+    pa_threaded_mainloop *mainloop; /**< PulseAudio event loop */
+    //uint32_t byterate; /**< bytes per second */
+};
+
+/* Context helpers */
+static void context_state_cb(pa_context *c, void *userdata)
+{
+    pa_threaded_mainloop *mainloop = userdata;
+
+    switch (pa_context_get_state(c)) {
+        case PA_CONTEXT_READY:
+        case PA_CONTEXT_FAILED:
+        case PA_CONTEXT_TERMINATED:
+            pa_threaded_mainloop_signal(mainloop, 0);
+        default:
+            break;
+    }
+}
+
+static bool context_wait(pa_threaded_mainloop *mainloop, pa_context *context)
+{
+    pa_context_state_t state;
+
+    while ((state = pa_context_get_state(context)) != PA_CONTEXT_READY) {
+        if (state == PA_CONTEXT_FAILED || state == PA_CONTEXT_TERMINATED)
+            return -1;
+        pa_threaded_mainloop_wait(mainloop);
+    }
+    return 0;
+}
+
+static void error(aout_instance_t *aout, const char *msg, pa_context *context)
+{
+    msg_Err(aout, "%s: %s", msg, pa_strerror(pa_context_errno(context)));
+}
+
+/* Stream helpers */
+static void stream_state_cb(pa_stream *s, void *userdata)
+{
+    pa_threaded_mainloop *mainloop = userdata;
+
+    switch (pa_stream_get_state(s)) {
+        case PA_STREAM_READY:
+        case PA_STREAM_FAILED:
+        case PA_STREAM_TERMINATED:
+            pa_threaded_mainloop_signal(mainloop, 0);
+        default:
+            break;
+    }
+}
+
+static void stream_moved_cb(pa_stream *s, void *userdata)
+{
+    vlc_object_t *obj = userdata;
+
+    msg_Dbg(obj, "connected to device %s (%u)",
+            pa_stream_get_device_name(s),
+            pa_stream_get_device_index(s));
+}
+
+static int stream_wait(pa_threaded_mainloop *mainloop, pa_stream *stream)
+{
+    pa_stream_state_t state;
+
+    while ((state = pa_stream_get_state(stream)) != PA_STREAM_READY) {
+        if (state == PA_STREAM_FAILED || state == PA_STREAM_TERMINATED)
+            return -1;
+        pa_threaded_mainloop_wait(mainloop);
+    }
+    return 0;
+}
+
+/* Memory free callback. The block_t address is in front of the data. */
+static void data_free(void *data)
+{
+    block_t **pp = data, *block;
+
+    memcpy(&block, pp - 1, sizeof (block));
+    block_Release(block);
+}
+
+static void *data_convert(block_t **pp)
+{
+    block_t *block = *pp;
+    /* In most cases, there is enough head room, and this is really cheap: */
+    block = block_Realloc(block, sizeof (block), block->i_buffer);
+    *pp = block;
+    if (unlikely(block == NULL))
+        return NULL;
+
+    memcpy(block->p_buffer, &block, sizeof (block));
+    block->p_buffer += sizeof (block);
+    block->i_buffer -= sizeof (block);
+    return block->p_buffer;
+}
+
+/*****************************************************************************
+ * Play: play a sound samples buffer
+ *****************************************************************************/
+static void Play(aout_instance_t *aout)
+{
+    aout_sys_t *sys = aout->output.p_sys;
+    pa_stream *s = sys->stream;
+
+    /* Note: The core already holds the output FIFO lock at this point.
+     * Therefore we must not under any circumstances (try to) acquire the
+     * output FIFO lock while the PulseAudio threaded main loop lock is held
+     * (including from PulseAudio stream callbacks). Otherwise lock inversion
+     * will take place, and sooner or later a deadlock. */
+    pa_threaded_mainloop_lock(sys->mainloop);
+
+    if (pa_stream_is_corked(sys->stream) > 0) {
+        pa_operation *op = pa_stream_cork(s, 0, NULL, NULL);
+        if (op != NULL)
+            pa_operation_unref(op);
+        msg_Dbg(aout, "uncorking");
+    }
+
+    /* This function should be called by the LibVLC core a header of time,
+     * but not more than AOUT_MAX_PREPARE. The PulseAudio latency should be
+     * shorter than that (though it might not be the case with some evil piece
+     * of audio output hardware). So we need to prepend the buffer with zeroes
+     * to keep audio and video in sync. */
+    pa_usec_t latency;
+    int negative;
+    if (pa_stream_get_latency(s, &latency, &negative) < 0) {
+        /* Especially at start of stream, latency may not be known (yet). */
+        if (pa_context_errno(sys->context) != PA_ERR_NODATA)
+            error(aout, "cannot determine latency", sys->context);
+        latency = 0;
+    }
+
+    mtime_t gap = aout_FifoFirstDate(aout, &aout->output.fifo) - mdate()
+                - latency;
+    if (gap > AOUT_PTS_TOLERANCE) {
+#if 0   /* FIXME: we need to take buffer status into account as well... */
+        size_t len = sys->byterate * gap / CLOCK_FREQ;
+        void *ptr = calloc(1, len);
+
+        msg_Dbg(aout, "buffer too early (%"PRId64" us), stuffing %zu bytes",
+                gap, len);
+        if (likely(ptr != NULL))
+            if (pa_stream_write(sys->stream, ptr, len, free,
+                                0, PA_SEEK_RELATIVE) < 0)
+                free(ptr);
+#endif
+        msleep(gap);
+    }
+    /*else if (latency != 0 && gap < -AOUT_PTS_TOLERANCE)
+        msg_Err(aout, "buffer too late (%"PRId64" us)", -gap);*/
+
+#if 0 /* Fault injector to test underrun recovery */
+    static unsigned u = 0;
+    if ((++u % 500) == 0) {
+        msg_Err(aout, "fault injection");
+        msleep(CLOCK_FREQ*2);
+    }
+#endif
+
+    /* This function is called exactly once per block in the output FIFO, so
+     * this for-loop is not necessary.
+     * If this function is changed to not always dequeue blocks, be sure to
+     * limit the queue size to a reasonable limit to avoid huge leaks. */
+    for (;;) {
+        block_t *block = aout_FifoPop(aout, &aout->output.fifo);
+        if (block == NULL)
+            break;
+
+        const void *ptr = data_convert(&block);
+        if (unlikely(ptr == NULL))
+            break;
+
+        size_t len = block->i_buffer;
+        //mtime_t pts = block->i_pts, duration = block->i_length;
+
+        if (pa_stream_write(s, ptr, len, data_free, 0, PA_SEEK_RELATIVE) < 0)
+        {
+            block_Release(block);
+            msg_Err(aout, "cannot write: %s",
+                    pa_strerror(pa_context_errno(sys->context)));
+        }
+    }
+
+    pa_threaded_mainloop_unlock(sys->mainloop);
+}
+
+
 /*****************************************************************************
  * Open: open the audio device
  *****************************************************************************/
-static int Open ( vlc_object_t *p_this )
+static int Open(vlc_object_t *obj)
 {
-    aout_instance_t *p_aout = (aout_instance_t *)p_this;
+    aout_instance_t *aout = (aout_instance_t *)obj;
 
     /* Sample format specification */
     struct pa_sample_spec ss;
 
-    switch(p_aout->output.output.i_format)
+    switch(aout->output.output.i_format)
     {
         case VLC_CODEC_F64B:
-            p_aout->output.output.i_format = VLC_CODEC_F32B;
+            aout->output.output.i_format = VLC_CODEC_F32B;
         case VLC_CODEC_F32B:
             ss.format = PA_SAMPLE_FLOAT32BE;
             break;
         case VLC_CODEC_F64L:
-            p_aout->output.output.i_format = VLC_CODEC_F32L;
+            aout->output.output.i_format = VLC_CODEC_F32L;
         case VLC_CODEC_F32L:
             ss.format = PA_SAMPLE_FLOAT32LE;
             break;
         case VLC_CODEC_FI32:
-            p_aout->output.output.i_format = VLC_CODEC_FL32;
+            aout->output.output.i_format = VLC_CODEC_FL32;
             ss.format = PA_SAMPLE_FLOAT32NE;
             break;
         case VLC_CODEC_S32B:
@@ -121,28 +281,28 @@ static int Open ( vlc_object_t *p_this )
             ss.format = PA_SAMPLE_S16LE;
             break;
         case VLC_CODEC_S8:
-            p_aout->output.output.i_format = VLC_CODEC_U8;
+            aout->output.output.i_format = VLC_CODEC_U8;
         case VLC_CODEC_U8:
             ss.format = PA_SAMPLE_U8;
             break;
         default:
             if (HAVE_FPU)
             {
-                p_aout->output.output.i_format = VLC_CODEC_FL32;
+                aout->output.output.i_format = VLC_CODEC_FL32;
                 ss.format = PA_SAMPLE_FLOAT32NE;
             }
             else
             {
-                p_aout->output.output.i_format = VLC_CODEC_S16N;
+                aout->output.output.i_format = VLC_CODEC_S16N;
                 ss.format = PA_SAMPLE_S16NE;
             }
             break;
     }
 
-    ss.rate = p_aout->output.output.i_rate;
-    ss.channels = aout_FormatNbChannels(&p_aout->output.output);
+    ss.rate = aout->output.output.i_rate;
+    ss.channels = aout_FormatNbChannels(&aout->output.output);
     if (!pa_sample_spec_valid(&ss)) {
-        msg_Err(p_aout, "unsupported sample specification");
+        msg_Err(aout, "unsupported sample specification");
         return VLC_EGENERIC;
     }
 
@@ -150,312 +310,163 @@ static int Open ( vlc_object_t *p_this )
     struct pa_channel_map map;
     map.channels = 0;
 
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_CENTER)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_CENTER)
     {
         if (ss.channels == 1)
             map.map[map.channels++] = PA_CHANNEL_POSITION_MONO;
         else
             map.map[map.channels++] = PA_CHANNEL_POSITION_FRONT_CENTER;
     }
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_LEFT)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_LEFT)
         map.map[map.channels++] = PA_CHANNEL_POSITION_FRONT_LEFT;
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_RIGHT)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_RIGHT)
         map.map[map.channels++] = PA_CHANNEL_POSITION_FRONT_RIGHT;
 
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_REARCENTER)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_REARCENTER)
         map.map[map.channels++] = PA_CHANNEL_POSITION_REAR_CENTER;
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_REARLEFT)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_REARLEFT)
         map.map[map.channels++] = PA_CHANNEL_POSITION_REAR_LEFT;
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_REARRIGHT)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_REARRIGHT)
         map.map[map.channels++] = PA_CHANNEL_POSITION_REAR_RIGHT;
 
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_MIDDLELEFT)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_MIDDLELEFT)
         map.map[map.channels++] = PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER;
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_MIDDLERIGHT)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_MIDDLERIGHT)
         map.map[map.channels++] = PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER;
 
-    if (p_aout->output.output.i_physical_channels & AOUT_CHAN_LFE)
+    if (aout->output.output.i_physical_channels & AOUT_CHAN_LFE)
         map.map[map.channels++] = PA_CHANNEL_POSITION_LFE;
 
     for (unsigned i = 0; map.channels < ss.channels; i++) {
         map.map[map.channels++] = PA_CHANNEL_POSITION_AUX0 + i;
-        msg_Warn(p_aout, "mapping channel %"PRIu8" to AUX%u", map.channels, i);
+        msg_Warn(aout, "mapping channel %"PRIu8" to AUX%u", map.channels, i);
     }
 
     if (!pa_channel_map_valid(&map)) {
-        msg_Err(p_aout, "unsupported channel map");
+        msg_Err(aout, "unsupported channel map");
         return VLC_EGENERIC;
     } else {
         const char *name = pa_channel_map_to_pretty_name(&map);
-        msg_Dbg(p_aout, "using %s channel map", (name != NULL) ? name : "?");
+        msg_Dbg(aout, "using %s channel map", (name != NULL) ? name : "?");
     }
 
     const pa_stream_flags_t flags = PA_STREAM_INTERPOLATE_TIMING
                                   | PA_STREAM_AUTO_TIMING_UPDATE
-                                  | PA_STREAM_ADJUST_LATENCY;
+                                  | PA_STREAM_ADJUST_LATENCY
+                                  | PA_STREAM_START_CORKED;
 
+    const uint32_t byterate = pa_bytes_per_second(&ss);
     struct pa_buffer_attr attr;
-    /* Reduce overall latency to 100mS to reduce audible clicks
-     * Also minreq and internal buffers are now 100ms to reduce resampling.
-     * But it still should not drop samples even with USB sound cards. */
-    attr.tlength = pa_bytes_per_second(&ss)/10;
-    attr.maxlength = attr.tlength * 2;
-    attr.prebuf = -1;
+    /* no point in larger buffers on PA side than VLC */
+    attr.maxlength = byterate * AOUT_MAX_ADVANCE_TIME / CLOCK_FREQ;
+    attr.tlength = byterate * AOUT_MAX_PREPARE_TIME / CLOCK_FREQ;
+    attr.prebuf = byterate * AOUT_MIN_PREPARE_TIME / CLOCK_FREQ;
     attr.minreq = -1;
     attr.fragsize = 0; /* not used for output */
 
     /* Allocate structures */
-    struct aout_sys_t *sys = malloc(sizeof(*sys));
+    aout_sys_t *sys = malloc(sizeof(*sys));
     if (unlikely(sys == NULL))
         return VLC_ENOMEM;
+    sys->context = NULL;
     sys->stream = NULL;
-    sys->start_date = VLC_TS_INVALID;
+    //sys->byterate = byterate;
 
-    sys->mainloop = pa_threaded_mainloop_new();
-    if (unlikely(sys->mainloop == NULL)) {
+    /* Allocate threaded main loop */
+    pa_threaded_mainloop *mainloop = pa_threaded_mainloop_new();
+    if (unlikely(mainloop == NULL)) {
         free(sys);
         return VLC_ENOMEM;
     }
+    sys->mainloop = mainloop;
 
-    char *ua = var_InheritString(p_aout, "user-agent");
-
-    sys->context = pa_context_new(
-                              pa_threaded_mainloop_get_api(sys->mainloop), ua);
-    free(ua);
-    if (unlikely(sys->context == NULL)) {
-        pa_threaded_mainloop_free(sys->mainloop);
+    if (pa_threaded_mainloop_start(mainloop) < 0) {
+        pa_threaded_mainloop_free(mainloop);
         free(sys);
         return VLC_ENOMEM;
     }
-
-    p_aout->output.p_sys = sys;
-    pa_context_set_state_callback(sys->context, context_state_cb, sys);
-    if (pa_context_connect(sys->context, NULL, 0, NULL) < 0) {
-connect_fail:
-        msg_Err(p_aout, "cannot connect to server: %s",
-                pa_strerror(pa_context_errno(sys->context)));
+    pa_threaded_mainloop_lock(mainloop);
+
+    /* Connect to PulseAudio server */
+    char *user_agent = var_InheritString(aout, "user-agent");
+    pa_context *ctx = pa_context_new(pa_threaded_mainloop_get_api(mainloop),
+                                     user_agent);
+    free(user_agent);
+    if (unlikely(ctx == NULL))
         goto fail;
-    }
+    sys->context = ctx;
 
-    if (pa_threaded_mainloop_start(sys->mainloop) < 0) {
-        msg_Err(p_aout, "cannot start main loop");
+    pa_context_set_state_callback(ctx, context_state_cb, mainloop);
+    if (pa_context_connect(ctx, NULL, 0, NULL) < 0
+     || context_wait(mainloop, ctx)) {
+        error(aout, "cannot connect to server", ctx);
         goto fail;
     }
 
-    pa_threaded_mainloop_lock(sys->mainloop);
-    /* Wait until the context is ready */
-    while (pa_context_get_state(sys->context) != PA_CONTEXT_READY) {
-        if (pa_context_get_state(sys->context) == PA_CONTEXT_FAILED)
-            goto connect_fail;
-        pa_threaded_mainloop_wait(sys->mainloop);
-    }
-
-    /* Create a stream */
-    sys->stream = pa_stream_new(sys->context, "audio stream", &ss, &map);
-    if (sys->stream == NULL) {
-        msg_Err(p_aout, "cannot create stream: %s",
-                pa_strerror(pa_context_errno(sys->context)));
-        goto unlock_and_fail;
-    }
-    pa_stream_set_state_callback(sys->stream, stream_state_cb, sys);
-    pa_stream_set_write_callback(sys->stream, stream_request_cb, p_aout);
-    if (pa_stream_connect_playback(sys->stream, NULL, &attr,
-                                   flags, NULL, NULL) < 0) {
-stream_fail:
-        msg_Err(p_aout, "cannot connect stream: %s",
-                pa_strerror(pa_context_errno(sys->context)));
-        goto unlock_and_fail;
+    /* Create a playback stream */
+    pa_stream *s = pa_stream_new(ctx, "audio stream", &ss, &map);
+    if (s == NULL) {
+        error(aout, "cannot create stream", ctx);
+        goto fail;
     }
+    sys->stream = s;
+    pa_stream_set_state_callback(s, stream_state_cb, mainloop);
+    pa_stream_set_moved_callback(s, stream_moved_cb, aout);
 
-    while (pa_stream_get_state(sys->stream) != PA_STREAM_READY) {
-        if (pa_stream_get_state(sys->stream) == PA_STREAM_FAILED)
-            goto stream_fail;
-        pa_threaded_mainloop_wait(sys->mainloop);
+    if (pa_stream_connect_playback(s, NULL, &attr, flags, NULL, NULL) < 0
+     || stream_wait(mainloop, s)) {
+        error(aout, "cannot connect stream", ctx);
+        goto fail;
     }
+    stream_moved_cb(s, aout);
 
-    msg_Dbg(p_aout, "Connected to device %s (%u, %ssuspended).",
-            pa_stream_get_device_name(sys->stream),
-            pa_stream_get_device_index(sys->stream),
-            pa_stream_is_suspended(sys->stream) ? "" : "not ");
-
-    const struct pa_buffer_attr *pba = pa_stream_get_buffer_attr(sys->stream);
-
-    p_aout->output.i_nb_samples = pba->minreq / pa_frame_size(&ss);
-    /* Set buffersize from pulseaudio defined minrequest */
-    sys->buffer_size = pba->minreq;
-    msg_Dbg(p_aout, "using buffer metrics: maxlength=%u, tlength=%u, "
+    const struct pa_buffer_attr *pba = pa_stream_get_buffer_attr(s);
+    msg_Dbg(aout, "using buffer metrics: maxlength=%u, tlength=%u, "
             "prebuf=%u, minreq=%u",
             pba->maxlength, pba->tlength, pba->prebuf, pba->minreq);
-    {
-        char sst[PA_SAMPLE_SPEC_SNPRINT_MAX];
-        msg_Dbg(p_aout, "using sample specification: %s",
-                pa_sample_spec_snprint(sst, sizeof(sst),
-                                     pa_stream_get_sample_spec(sys->stream)));
-    }
-    {
-        char cmt[PA_CHANNEL_MAP_SNPRINT_MAX];
-        msg_Dbg(p_aout, "using channel map: %s",
-                pa_channel_map_snprint(cmt, sizeof(cmt),
-                                      pa_stream_get_channel_map(sys->stream)));
-    }
-    pa_threaded_mainloop_unlock(sys->mainloop);
 
-    p_aout->output.pf_play = Play;
-    aout_VolumeSoftInit(p_aout);
+    aout->output.i_nb_samples = pba->minreq / pa_frame_size(&ss);
+    pa_threaded_mainloop_unlock(mainloop);
+
+    aout->output.p_sys = sys;
+    aout->output.pf_play = Play;
+    aout_VolumeSoftInit(aout);
     return VLC_SUCCESS;
 
-unlock_and_fail:
-    pa_threaded_mainloop_unlock(sys->mainloop);
 fail:
-    Close(p_this);
+    pa_threaded_mainloop_unlock(mainloop);
+    Close(obj);
     return VLC_EGENERIC;
 }
 
-/*****************************************************************************
- * Play: play a sound samples buffer
- *****************************************************************************/
-static void Play(aout_instance_t * aout)
-{
-    struct aout_sys_t *sys = aout->output.p_sys;
-
-    if (likely(sys->start_date != VLC_TS_INVALID))
-        return;
-    pa_threaded_mainloop_lock(sys->mainloop);
-    sys->start_date = aout_FifoFirstDate(aout, &aout->output.fifo);
-    pa_threaded_mainloop_unlock(sys->mainloop);
-}
-
 /*****************************************************************************
  * Close: close the audio device
  *****************************************************************************/
 static void Close (vlc_object_t *obj)
 {
     aout_instance_t *aout = (aout_instance_t *)obj;
-    struct aout_sys_t *sys = aout->output.p_sys;
-
-    if (sys->stream) {
-        pa_operation *o;
-
-        pa_threaded_mainloop_lock(sys->mainloop);
-        pa_stream_set_write_callback(sys->stream, NULL, NULL);
-
-        o = pa_stream_flush(sys->stream, success_cb, sys);
-        if (o != NULL) {
-            while (pa_operation_get_state(o) == PA_OPERATION_RUNNING)
-                pa_threaded_mainloop_wait(sys->mainloop);
-            pa_operation_unref(o);
-        }
-
-        o = pa_stream_drain(sys->stream, success_cb, sys);
-        if (o != NULL) {
-            while (pa_operation_get_state(o) == PA_OPERATION_RUNNING)
-                pa_threaded_mainloop_wait(sys->mainloop);
-            pa_operation_unref(o);
-        }
-
-        pa_threaded_mainloop_unlock(sys->mainloop);
-    }
-
-    pa_threaded_mainloop_stop(sys->mainloop);
-    if (sys->stream) {
-        pa_stream_disconnect(sys->stream);
-        pa_stream_unref(sys->stream);
+    aout_sys_t *sys = aout->output.p_sys;
+    pa_threaded_mainloop *mainloop = sys->mainloop;
+    pa_context *ctx = sys->context;
+    pa_stream *s = sys->stream;
+
+    pa_threaded_mainloop_lock(mainloop);
+    if (s != NULL) {
+        pa_operation *op;
+
+        pa_stream_set_write_callback(s, NULL, NULL);
+        op = pa_stream_flush(s, NULL, NULL);
+        if (op != NULL)
+            pa_operation_unref(op);
+        op = pa_stream_drain(s, NULL, NULL);
+        if (op != NULL)
+            pa_operation_unref(op);
+        pa_stream_disconnect(s);
+        pa_stream_unref(s);
     }
-    pa_context_disconnect(sys->context);
-    pa_context_unref(sys->context);
-    pa_threaded_mainloop_free(sys->mainloop);
+    if (ctx != NULL)
+        pa_context_unref(ctx);
+    pa_threaded_mainloop_unlock(mainloop);
+    pa_threaded_mainloop_free(mainloop);
     free(sys);
 }
-
-static void context_state_cb(pa_context *c, void *userdata)
-{
-    struct aout_sys_t *sys = userdata;
-
-    switch (pa_context_get_state(c)) {
-        case PA_CONTEXT_READY:
-        case PA_CONTEXT_FAILED:
-            pa_threaded_mainloop_signal(sys->mainloop, 0);
-        default:
-            break;
-    }
-}
-
-static void stream_state_cb(pa_stream *s, void *userdata)
-{
-    struct aout_sys_t *sys = userdata;
-
-    switch (pa_stream_get_state(s)) {
-        case PA_STREAM_READY:
-        case PA_STREAM_FAILED:
-            pa_threaded_mainloop_signal(sys->mainloop, 0);
-        default:
-            break;
-    }
-}
-
-/* Memory free callback. The block_t address is in front of the data. */
-static void block_free_cb(void *data)
-{
-    block_t **pp = data, *block;
-
-    memcpy(&block, pp - 1, sizeof (block));
-    block_Release(block);
-}
-
-static void stream_request_cb(pa_stream *s, size_t length, void *userdata)
-{
-    aout_instance_t *aout = userdata;
-    struct aout_sys_t *sys = aout->output.p_sys;
-    size_t buffer_size = sys->buffer_size;
-
-    do {
-        block_t *block = NULL;
-
-        if (sys->start_date != VLC_TS_INVALID) {
-            pa_usec_t latency;
-            int negative;
-
-            if (pa_stream_get_latency(s, &latency, &negative) < 0){
-                if (pa_context_errno(sys->context) != PA_ERR_NODATA) {
-                    msg_Err(aout, "cannot determine latency: %s",
-                            pa_strerror(pa_context_errno(sys->context)));
-                }
-                latency = 0;
-
-            }
-
-            //msg_Dbg(p_aout, "latency=%"PRId64, latency);
-            mtime_t next_date = mdate() + latency;
-
-            if (sys->start_date < next_date + AOUT_PTS_TOLERANCE)
-                block = aout_OutputNextBuffer(aout, next_date, 0);
-        }
-
-        if (block != NULL)
-            /* PA won't let us pass a reference to the buffer meta data... */
-            block = block_Realloc (block, sizeof (block), block->i_buffer);
-        if (block != NULL) {
-            memcpy(block->p_buffer, &block, sizeof (block));
-            block->p_buffer += sizeof (block);
-            block->i_buffer -= sizeof (block);
-
-            length -= block->i_buffer;
-            pa_stream_write(s, block->p_buffer, block->i_buffer,
-                            block_free_cb, 0, PA_SEEK_RELATIVE);
-        } else {
-            void *data = pa_xmalloc(length);
-            memset(data, 0, length);
-            pa_stream_write(s, data, length, pa_xfree, 0, PA_SEEK_RELATIVE);
-            length = 0;
-        }
-    } while (length > buffer_size);
-}
-
-static void success_cb(pa_stream *s, int sucess, void *userdata)
-{
-    struct aout_sys_t *sys = userdata;
-
-    (void) s;
-    (void) sucess;
-    pa_threaded_mainloop_signal(sys->mainloop, 0);
-}