ao_wasapi: Implement per-application mixing

The volume controls in mpv now affect the session's volume (the
application's volume in the mixer). Since we do not request a
non-persistent session, the volume and mute status persist across mpv
invocations and system reboots.

In exclusive mode, WASAPI doesn't have access to a mixer so the endpoint
(sound card)'s master volume is modified instead. Since by definition
mpv is the only thing outputting audio in exclusive mode, this causes no
conflict, and ao_wasapi restores the last user-set volume when it's
uninitialized.

1 files changed, 5 insertions, 0 deletions

diff --git a/audio/out/ao_wasapi.h b/audio/out/ao_wasapi.h
index a0ce654d4d..d17b2504a0 100755
--- a/audio/out/ao_wasapi.h
+++ b/audio/out/ao_wasapi.h
@@ -41,6 +41,8 @@ typedef struct wasapi_state {
     /* volume control */
     DWORD vol_hw_support, status;
     float audio_volume;
+    float previous_volume;
+    float initial_volume;
 
     /* Buffers */
     size_t buffer_block_size; /* Size of each block in bytes */
@@ -54,6 +56,7 @@ typedef struct wasapi_state {
     IMMDevice *pDevice;
     IAudioClient *pAudioClient;
     IAudioRenderClient *pRenderClient;
+    ISimpleAudioVolume *pAudioVolume;
     IAudioEndpointVolume *pEndpointVolume;
     HANDLE hFeed; /* wasapi event */
     HANDLE hForceFeed; /* forces writing a buffer (e.g. before audio_resume) */
@@ -65,12 +68,14 @@ typedef struct wasapi_state {
     /* WASAPI proxy handles, for Single-Threaded Apartment communication.
        One is needed for each object that's accessed by a different thread. */
     IAudioClient *pAudioClientProxy;
+    ISimpleAudioVolume *pAudioVolumeProxy;
     IAudioEndpointVolume *pEndpointVolumeProxy;
 
     /* Streams used to marshal the proxy objects. The thread owning the actual objects
        needs to marshal proxy objects into these streams, and the thread that wants the
        proxies unmarshals them from here. */
     IStream *sAudioClient;
+    IStream *sAudioVolume;
     IStream *sEndpointVolume;
 
     /* WASAPI internal clock information, for estimating delay */