[vlc-devel] [PATCH 2/7] mmdevice: follow default device changes

[Rémi Denis-Courmont]

Le 27 février 2018 12:41:06 GMT+02:00, Thomas Guillem <thomas at gllm.fr> a écrit :
>Restart and request the new default device when it's changed by Windows
>and
>when the "Default" virtual device is selected by VLC.
>
>Refs #19638
>---
> modules/audio_output/mmdevice.c | 31 ++++++++++++++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
>diff --git a/modules/audio_output/mmdevice.c
>b/modules/audio_output/mmdevice.c
>index 48d05ad2d6..525f16ff6a 100644
>--- a/modules/audio_output/mmdevice.c
>+++ b/modules/audio_output/mmdevice.c
>@@ -37,6 +37,7 @@ DEFINE_PROPERTYKEY(PKEY_Device_FriendlyName,
>0xa45c254e, 0xdf1c, 0x4efd,
>    0x80, 0x20, 0x67, 0xd1, 0x46, 0xa8, 0x50, 0xe0, 14);
> 
> #include <vlc_common.h>
>+#include <vlc_atomic.h>
> #include <vlc_plugin.h>
> #include <vlc_aout.h>
> #include <vlc_charset.h>
>@@ -93,6 +94,7 @@ struct aout_sys_t
>     float requested_volume; /**< Requested volume, negative if none */
>   signed char requested_mute; /**< Requested mute, negative if none */
>wchar_t *acquired_device; /**< Acquired device identifier, NULL if none
>*/
>+    atomic_bool request_default_device;
>     CRITICAL_SECTION lock;
>     CONDITION_VARIABLE work;
>     CONDITION_VARIABLE ready;
>@@ -136,11 +138,30 @@ static int TimeGet(audio_output_t *aout, mtime_t
>*restrict delay)
>     return SUCCEEDED(hr) ? 0 : -1;
> }
> 
>+static bool CheckDefaultDevice(audio_output_t *aout)
>+{
>+    aout_sys_t *sys = aout->sys;
>+    if (!atomic_exchange(&sys->request_default_device, false))
>+        return false;
>+
>+    if (sys->acquired_device != default_device)
>+        return false;
>+
>+    DeviceSelect(aout, NULL);
>+    return true; /* Should restart */
>+}
>+
> static void Play(audio_output_t *aout, block_t *block)
> {
>     aout_sys_t *sys = aout->sys;
>     HRESULT hr;
> 
>+    if (CheckDefaultDevice(aout))
>+    {
>+        block_Release(block);
>+        return;
>+    }
>+
>     EnterMTA();
>     hr = aout_stream_Play(sys->stream, block);
>     LeaveMTA();
>@@ -166,6 +187,9 @@ static void Flush(audio_output_t *aout, bool wait)
>     aout_sys_t *sys = aout->sys;
>     HRESULT hr;
> 
>+    if (CheckDefaultDevice(aout))
>+        return;
>+
>     EnterMTA();
>     hr = aout_stream_Flush(sys->stream, wait);
>     LeaveMTA();
>@@ -571,7 +595,9 @@
>vlc_MMNotificationClient_OnDefaultDeviceChange(IMMNotificationClient
>*this,
>     if (role != eConsole)
>         return S_OK;
> 
>-    msg_Dbg(aout, "default device changed: %ls", wid); /* TODO?
>migrate */
>+    msg_Dbg(aout, "default device changed: %ls", wid);
>+    atomic_store(&sys->request_default_device, true);
>+
>     return S_OK;
> }
> 
>@@ -1089,6 +1115,8 @@ static int Start(audio_output_t *aout,
>audio_sample_format_t *restrict fmt)
> {
>     aout_sys_t *sys = aout->sys;
> 
>+    CheckDefaultDevice(aout);
>+
>     if (sys->dev == NULL)
>         return -1;
> 
>@@ -1225,6 +1253,7 @@ static int Open(vlc_object_t *obj)
>     sys->duck.lpVtbl = &vlc_AudioVolumeDuckNotification;
>     sys->refs = 1;
>     sys->ducks = 0;
>+    atomic_init(&sys->request_default_device, false);
> 
>     sys->gain = 1.f;
>     sys->requested_device = default_device;
>-- 
>2.11.0
>
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There is already an atomic function to change device. I can hardly fathom why another one should be needed.

Also, this does not look like it will do the right thing if audio is inactive at the time of external change.
-- 
Remi Denis-Courmont