mpv/audio/out/ao_wasapi_changenotify.c

/*
 * This file is part of mpv.
 *
 * Original author: Jonathan Yong <10walls@gmail.com>
 *
 * mpv is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mpv 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 General Public License along
 * with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#define COBJMACROS 1
#define _WIN32_WINNT 0x600

#include <initguid.h>
#include <audioclient.h>
#include <endpointvolume.h>
#include <mmdeviceapi.h>
#include <wchar.h>
#include <stdlib.h>

#include "ao_wasapi.h"
#include "ao_wasapi_utils.h"

static char* ERole_to_str(ERole role)
{
    switch(role){
    case eConsole:        return "console";
    case eMultimedia:     return "multimedia";
    case eCommunications: return "communications";
    default:              return "<Unknown>";
    }
}

static char* EDataFlow_to_str(EDataFlow flow)
{
    switch(flow){
    case eRender:  return "render";
    case eCapture: return "capture";
    case eAll:     return "all";
    default:       return "<Unknown>";
    }
}

static HRESULT STDMETHODCALLTYPE sIMMNotificationClient_QueryInterface(
    IMMNotificationClient* This, REFIID riid, void **ppvObject)
{
    /* Compatible with IMMNotificationClient and IUnknown */
    if ( IsEqualGUID(&IID_IMMNotificationClient, riid) ||
         IsEqualGUID(&IID_IUnknown, riid) ) {
        *ppvObject = (void *)This;
        return S_OK;
    } else {
        *ppvObject = NULL;
        return E_NOINTERFACE;
    }
}

/* these are required, but not actually used */
static ULONG STDMETHODCALLTYPE sIMMNotificationClient_AddRef(
    IMMNotificationClient *This)
{
    return 1;
}

/* MSDN says it should free itself, but we're static */
static ULONG STDMETHODCALLTYPE sIMMNotificationClient_Release(
    IMMNotificationClient *This)
{
    return 1;
}

static HRESULT STDMETHODCALLTYPE sIMMNotificationClient_OnDeviceStateChanged(
    IMMNotificationClient *This,
    LPCWSTR pwstrDeviceId,
    DWORD dwNewState)
{
    change_notify *change = (change_notify *)This;
    struct ao *ao = change->ao;

    if (pwstrDeviceId && !wcscmp(change->monitored, pwstrDeviceId)){
        switch (dwNewState) {
        case DEVICE_STATE_DISABLED:
        case DEVICE_STATE_NOTPRESENT:
        case DEVICE_STATE_UNPLUGGED:
            MP_VERBOSE(ao,
                       "OnDeviceStateChange triggered - requesting ao reload\n");
            ao_request_reload(ao);
        case DEVICE_STATE_ACTIVE:
        default:
            return S_OK;
        }
    }
    return S_OK;
}

static HRESULT STDMETHODCALLTYPE sIMMNotificationClient_OnDeviceAdded(
    IMMNotificationClient *This,
    LPCWSTR pwstrDeviceId)
{
    change_notify *change = (change_notify *)This;
    struct ao *ao = change->ao;

    MP_VERBOSE(ao, "OnDeviceAdded triggered\n");
    if(pwstrDeviceId)
        MP_VERBOSE(ao, "New device %S\n",pwstrDeviceId);
    return S_OK;
}

/* maybe MPV can go over to the prefered device once it is plugged in? */
static HRESULT STDMETHODCALLTYPE sIMMNotificationClient_OnDeviceRemoved(
    IMMNotificationClient *This,
    LPCWSTR pwstrDeviceId)
{
    change_notify *change = (change_notify *)This;
    struct ao *ao = change->ao;

    if (pwstrDeviceId && !wcscmp(change->monitored, pwstrDeviceId)) {
        MP_VERBOSE(ao, "OnDeviceRemoved triggered - requesting ao reload\n");
        ao_request_reload(ao);
    }
    return S_OK;
}

static HRESULT STDMETHODCALLTYPE sIMMNotificationClient_OnDefaultDeviceChanged(
    IMMNotificationClient *This,
    EDataFlow flow,
    ERole role,
    LPCWSTR pwstrDeviceId)
{
    change_notify *change = (change_notify *)This;
    struct ao *ao = change->ao;
    struct wasapi_state *state = (struct wasapi_state *)ao->priv;

    MP_VERBOSE(ao, "OnDefaultDeviceChanged triggered for role:%s flow:%s\n",
               ERole_to_str(role), EDataFlow_to_str(flow));
    if(pwstrDeviceId)
        MP_VERBOSE(ao, "New default device %S\n", pwstrDeviceId);

    /* don't care about "eCapture" or non-"eMultimedia" roles  */
    if ( flow == eCapture ||
         role != eMultimedia ) return S_OK;

    /* stay on the device the user specified */
    if (state->opt_device) {
        MP_VERBOSE(ao, "Staying on specified device \"%s\"", state->opt_device);
        return S_OK;
    }

    /* don't reload if already on the new default */
    if ( pwstrDeviceId && !wcscmp(change->monitored, pwstrDeviceId) ){
        MP_VERBOSE(ao, "Already using default device, no reload required\n");
        return S_OK;
    }

    /* if we got here, we need to reload */
    ao_request_reload(ao);
    MP_VERBOSE(ao, "Requesting ao reload\n");
    return S_OK;
}

static HRESULT STDMETHODCALLTYPE sIMMNotificationClient_OnPropertyValueChanged(
    IMMNotificationClient *This,
    LPCWSTR pwstrDeviceId,
    const PROPERTYKEY key)
{
    change_notify *change = (change_notify *)This;
    struct ao *ao = change->ao;

    if (pwstrDeviceId && !wcscmp(change->monitored, pwstrDeviceId)) {
        MP_VERBOSE(ao, "OnPropertyValueChanged triggered\n");
        MP_VERBOSE(ao, "Changed property: ");
        if ( IsEqualPropertyKey(PKEY_AudioEngine_DeviceFormat, key) ) {
            MP_VERBOSE(change->ao,
                       "PKEY_AudioEngine_DeviceFormat - requesting ao reload\n");
            ao_request_reload(change->ao);
        } else {
            MP_VERBOSE(ao, "%s\n", mp_PKEY_to_str(&key));
        }
    }
    return S_OK;
}

static CONST_VTBL IMMNotificationClientVtbl sIMMDeviceEnumeratorVtbl_vtbl = {
    .QueryInterface = sIMMNotificationClient_QueryInterface,
    .AddRef = sIMMNotificationClient_AddRef,
    .Release = sIMMNotificationClient_Release,
    .OnDeviceStateChanged = sIMMNotificationClient_OnDeviceStateChanged,
    .OnDeviceAdded = sIMMNotificationClient_OnDeviceAdded,
    .OnDeviceRemoved = sIMMNotificationClient_OnDeviceRemoved,
    .OnDefaultDeviceChanged = sIMMNotificationClient_OnDefaultDeviceChanged,
    .OnPropertyValueChanged = sIMMNotificationClient_OnPropertyValueChanged,
};


HRESULT wasapi_change_init(struct ao *ao)
{
    MP_DBG(ao, "Setting up monitoring on playback device\n");
    struct wasapi_state *state = (struct wasapi_state *)ao->priv;
    struct change_notify *change = &state->change;
    /* COM voodoo to emulate c++ class */
    change->client.lpVtbl = &sIMMDeviceEnumeratorVtbl_vtbl;

    /* so the callbacks can access the ao */
    change->ao = ao;

    /* get the device string to compare with the pwstrDeviceId argument in callbacks */
    HRESULT hr = IMMDevice_GetId(state->pDevice, &change->monitored);
    EXIT_ON_ERROR(hr);

    /* register the change notification client */
    hr = IMMDeviceEnumerator_RegisterEndpointNotificationCallback(
        state->pEnumerator, (IMMNotificationClient *)change);
    EXIT_ON_ERROR(hr);

    MP_VERBOSE(state, "Monitoring changes in device: %S\n", state->change.monitored);
    return hr;
exit_label:
    MP_ERR(state, "Error setting up device change monitoring: %s\n",
           wasapi_explain_err(hr));
    wasapi_change_uninit(ao);
    return hr;
}

void wasapi_change_uninit(struct ao *ao)
{
    struct wasapi_state *state = (struct wasapi_state *)ao->priv;
    struct change_notify *change = &state->change;

    if( state->pEnumerator && change->client.lpVtbl )
        IMMDeviceEnumerator_UnregisterEndpointNotificationCallback(
            state->pEnumerator, (IMMNotificationClient *)change);

    if (change->monitored) CoTaskMemFree(change->monitored);
}