在 Firefox 中的 MediaStream 问题中没有音轨

如何解决在 Firefox 中的 MediaStream 问题中没有音轨

我正在使用 getdisplayMedia 和 getUserMedia 捕获用户屏幕和音频，并且能够记录完整的屏幕捕获。但这仅适用于 Chrome 而不适用于 Firefox。当我在 Firefox 上运行我的应用程序时，它会抛出错误“DOMException：AudioContext.createmediastreamsource：MediaStream 中没有音轨”。下面是我的代码片段。我安装了两个浏览器的最新版本。任何帮助，将不胜感激。提前致谢。

注意：-它在 context.createmediastreamsource(desktopStream)

行上抛出错误

async function captureScreen() {
    desktopStream = await navigator.mediaDevices.getdisplayMedia({ video: true,audio: true });
    microPhonestream = await navigator.mediaDevices.getUserMedia({ video: false,audio: true });

    const tracks = [
        ...desktopStream.getVideoTracks(),...mergeAudioStreams(desktopStream,microPhonestream)
    ];
    stream = new MediaStream(tracks);
    var options = { mimeType: "video/webm; codecs=opus,vp8" };
    startRecording(stream,options);
    ....
    ....
    ....
}


//merges two audio streams into one
const mergeAudioStreams = (desktopStream,microPhonestream) => {
    const context = new AudioContext();
    try {
        const source1 = context.createmediastreamsource(desktopStream);
        const source2 = context.createmediastreamsource(microPhonestream);
        const destination = context.createMediaStreamDestination();

        const desktopGain = context.createGain();
        const voiceGain = context.createGain();

        desktopGain.gain.value = 0.7;
        voiceGain.gain.value = 0.7;

        source1.connect(desktopGain).connect(destination);
        source2.connect(voiceGain).connect(destination);
        return destination.stream.getAudioTracks();
    }
    catch (err) {
    console.log(err);
    }
};

解决方法

Firefox 目前不支持使用 getDisplayMedia 捕获音频。它有一个 feature request。

您可以做的是在创建音频节点之前检查您的流是否有任何音轨，如下所示：

const destination = context.createMediaStreamDestination();

if (desktopStream.getAudioTracks().length) {
    const source1 = context.createMediaStreamSource(desktopStream);
    const desktopGain = context.createGain();
    desktopGain.gain.value = 0.7;
    source1.connect(desktopGain).connect(destination);
}

if (microPhoneStream.getAudioTracks().length) {
    const source2 = context.createMediaStreamSource(microPhoneStream);
    const voiceGain = context.createGain();
    voiceGain.gain.value = 0.7;
    source2.connect(voiceGain).connect(destination);
}

return destination.stream.getAudioTracks();