javascript - 用 arrayBuffer 录制 mp3

Question

我用 Stackoverflow 尝试了很多东西，但我做不到。所以我尝试用 nodejs (1) 从树莓派录制音频。在这个流通过一个 websocket 服务器之后(我没有放这段代码，因为它只是一个重定向)。最后一个在vuejs中的websocket监听流。在我想以 mp3 (2) 格式录制此流之后。但我有噪音或没有。1 - 树莓派:

ai = new audio.AudioIO({
        inOptions: {
          channelCount: 1,
          sampleFormat: audio.SampleFormat16Bit,
          sampleRate: 44100,
          deviceId: 6, // Use -1 or omit the deviceId to select the default device
          closeOnError: true // Close the stream if an audio error is detected, if set false then just log the error
        }
      });

      ai.on('data', buf => {
      
      clientAudioWebsocket.send(buf)
      }
      );
      
     
      ai.start();  

2-部分vuejs

• 套接字:

   this.dataBuffer = []
  
     var self = this
  
     var connectionToLocalServer = new WebSocket("ws://"+ip  +":4444")
     connectionToLocalServer.binaryType = "arraybuffer"
  
      connectionToLocalServer.onmessage = function(event) {
          self.dataBuffer.push(event.data);
  
      }
      connectionToLocalServer.onopen = function(event) {
  
  
    }
  

• 部分arraybuffer到mp3

    concatArrayBuffers (bufs) {
                            var offset = 0;
                            var bytes = 0;
                            var bufs2=bufs.map(function(buf,total){
                                bytes += buf.byteLength;
                                return buf;
                            });
                            var buffer = new ArrayBuffer(bytes);
                            var store = new Uint8Array(buffer);
                            bufs2.forEach(function(buf){
                                store.set(new Uint8Array(buf.buffer||buf,buf.byteOffset),offset);
                                offset += buf.byteLength;
                            });
                            return buffer }
  
  
  
            this.tmpResult = this.concatArrayBuffers(this.dataBuffer);
  
            var mp3Data = [];
  
            var mp3encoder = new lamejs.Mp3Encoder(1, 44100, 128);
  
            var mp3Tmp = mp3encoder.encodeBuffer(this.tmpResult, 0, Math.floor(this.tmpResult.byteLength / 2)); 
          //Push encode buffer to mp3Data variable
            mp3Data.push(mp3Tmp);
  
            // Get end part of mp3
            mp3Tmp = mp3encoder.flush();
  
            // Write last data to the output data, too
            // mp3Data contains now the complete mp3Data
            mp3Data.push(mp3Tmp);
  

而且我不明白为什么我有 16384 大小缓冲区的 arraybuffer。我真的对任何解决方案持开放态度，但我不想在服务器端进行。谢谢

Answer 1

所以我找到了解决方案，这是因为我没有创建 Int16Array :-((有时去外面 1 小时后你会找到解决方案会更好)

解决方案是:

let tmpResult = this.concatArrayBuffers(this.dataBuffer)
     
var samples = new Int16Array(tmpResult);
var buffer = [];
var mp3enc = new lamejs.Mp3Encoder(1, 44100, 128);
var remaining = samples.length;
var maxSamples = 1152;
for (var i = 0; remaining >= maxSamples; i += maxSamples) {
     var mono = samples.subarray(i, i + maxSamples);
     var mp3buf = mp3enc.encodeBuffer(mono);
     if (mp3buf.length > 0) {
         buffer.push(new Int8Array(mp3buf));
        }
        remaining -= maxSamples;
}
var d = mp3enc.flush();
if(d.length > 0){
 buffer.push(new Int8Array(d));
}

console.log('done encoding, size=', buffer.length);
var blob = new Blob(buffer, {type: 'audio/mp3'});