检查系统音量是否静音？

Question

我正在开发一个为部分程序播放音频的项目。我希望能够在用户的系统音量静音时显示一条消息。我在 Windows 上使用 Python。

Answer 1

使用 Windows 混合器 API。我给你找到了这篇文章，并附上了相关代码：
（来自 MS KB 181550：“监视音频音量级别”）

这是用 C 编写的，但也可以“翻译”为 Python。

我希望这有帮助。

#include <windows.h>
#include <mmsystem.h>

MMRESULT rc;              // Return code.
HMIXER hMixer;            // Mixer handle used in mixer API calls.
MIXERCONTROL mxc;         // Holds the mixer control data.
MIXERLINE mxl;            // Holds the mixer line data.
MIXERLINECONTROLS mxlc;   // Obtains the mixer control.

// Open the mixer. This opens the mixer with a deviceID of 0. If you
// have a single sound card/mixer, then this will open it. If you have
// multiple sound cards/mixers, the deviceIDs will be 0, 1, 2, and
// so on.
rc = mixerOpen(&hMixer, 0,0,0,0);
if (MMSYSERR_NOERROR != rc) {
    // Couldn't open the mixer.
}

// Initialize MIXERLINE structure.
ZeroMemory(&mxl,sizeof(mxl));
mxl.cbStruct = sizeof(mxl);

// Specify the line you want to get. You are getting the input line
// here. If you want to get the output line, you need to use
// MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT.
mxl.dwComponentType = MIXERLINE_COMPONENTTYPE_DST_WAVEIN;

rc = mixerGetLineInfo((HMIXEROBJ)hMixer, &mxl,
                       MIXER_GETLINEINFOF_COMPONENTTYPE);
if (MMSYSERR_NOERROR == rc) {
    // Couldn't get the mixer line.
}

// Get the control.
ZeroMemory(&mxlc, sizeof(mxlc));
mxlc.cbStruct = sizeof(mxlc);
mxlc.dwLineID = mxl.dwLineID;
mxlc.dwControlType = MIXERCONTROL_CONTROLTYPE_PEAKMETER;
mxlc.cControls = 1;
mxlc.cbmxctrl = sizeof(mxc);
mxlc.pamxctrl = &mxc;
ZeroMemory(&mxc, sizeof(mxc));
mxc.cbStruct = sizeof(mxc);
rc = mixerGetLineControls((HMIXEROBJ)hMixer,&mxlc,
                           MIXER_GETLINECONTROLSF_ONEBYTYPE);
if (MMSYSERR_NOERROR != rc) {
    // Couldn't get the control.
}

// After successfully getting the peakmeter control, the volume range
// will be specified by mxc.Bounds.lMinimum to mxc.Bounds.lMaximum.

MIXERCONTROLDETAILS mxcd;             // Gets the control values.
MIXERCONTROLDETAILS_SIGNED volStruct; // Gets the control values.
long volume;                          // Holds the final volume value.

// Initialize the MIXERCONTROLDETAILS structure
ZeroMemory(&mxcd, sizeof(mxcd));
mxcd.cbStruct = sizeof(mxcd);
mxcd.cbDetails = sizeof(volStruct);
mxcd.dwControlID = mxc.dwControlID;
mxcd.paDetails = &volStruct;
mxcd.cChannels = 1;

// Get the current value of the peakmeter control. Typically, you
// would set a timer in your program to query the volume every 10th
// of a second or so.
rc = mixerGetControlDetails((HMIXEROBJ)hMixer, &mxcd,
                             MIXER_GETCONTROLDETAILSF_VALUE);
if (MMSYSERR_NOERROR == rc) {
    // Couldn't get the current volume.
}
volume = volStruct.lValue;

// Get the absolute value of the volume.
if (volume < 0)
    volume = -volume;