Question

我在html页面中有一个.wav音频，并想使用javascript录制。我想从演讲者那里录音。音频正在播放，正在发送到扬声器，并且支持格式，但mediaRecorder（）并未记录声音。下载文件后，文件为空。

我不确定接下来要检查什么？

//start playing sound button, html page
document.querySelector(".start").addEventListener("click", function() {
audioZero.play();
});

//start recording sound button, html page
document.querySelector(".startrec").addEventListener("click", function() {
    mediaRecorder.start();
    console.log("recorder started");
 });

 //stop recording sound button, html page
 document.querySelector(".stoprec").addEventListener("click", function() {
    mediaRecorder.requestData();
    mediaRecorder.stop();
 });

let audioContext = new AudioContext();

//get sound 
let audioZero = document.getElementById("audio0")

// creates a link between audio context and file
const maracas = audioContext.createMediaElementSource(audioZero)

let gainNode = audioContext.createGain()
maracas.connect(gainNode)

// creates link to the speaker
gainNode.connect(audioContext.destination);
console.log(audioContext.destination);

gainNode.gain.value = 1;

//Gets stream of data from the speaker output - gives the ability to store
const dest = audioContext.createMediaStreamDestination();

//This records the stream 
var mediaRecorder = new MediaRecorder(dest.stream);

let chunks = [];

//when data is available an event is raised, this listens for it
mediaRecorder.ondataavailable = function(evt) {
    console.log(evt, evt.data);
    chunks.push(evt.data);
};

mediaRecorder.onstop = function(evt) {
   // Make blob out of our blobs, and open it.
   var blob = new Blob(chunks, { 'type' : "audio/webm;codecs=opus" });

   var anchorTag = document.createElement("a");
   anchorTag.setAttribute('download', 'download');
   anchorTag.innerHTML="download me";

   // creates the download link
   anchorTag.href = URL.createObjectURL(blob);

   document.body.appendChild(anchorTag);

   chunks = [];

};

Answer 1

创建MediaStreamDestinationNode之后，您需要将音频图的发声部分连接到它-它不会自动将所有声音发送到audioContext.destination，只是因为它是另一个目标节点。（您无法记录“所有与发言者有关的内容”，这可能是跨域冲突。）

在创建“目标”节点之后立即添加以下行：

gainNode.connect(dest);

您也确实需要在某个时候调用mediaRecorder.start（）-不知道这是否不在您的代码段中。

MediaRecoder未录制HTML5音频

1 个答案: