如何用js将blob为pcm格式转换为MP3格式

const arrayBuffer = await blob.arrayBuffer();

const audioContext = new AudioContext();
const audioBufferSourceNode = audioContext.createBufferSource();

const audioBuffer = await audioContext.decodeAudioData(arrayBuffer);

const mp3Encoder = new lamejs.Mp3Encoder(2, audioBuffer.sampleRate, 128);
const leftChannel = audioBuffer.getChannelData(0);
const rightChannel = audioBuffer.getChannelData(1);
const interleaved = interleave(leftChannel, rightChannel);
const mp3Data = mp3Encoder.encodeBuffer(interleaved);
mp3Data.push(...mp3Encoder.flush());

const mp3Blob = new Blob([new Uint8Array(mp3Data)], { type: 'audio/mp3' });

async function convertToMp3(blob) {
  const arrayBuffer = await blob.arrayBuffer();
  const audioContext = new AudioContext();
  const audioBufferSourceNode = audioContext.createBufferSource();
  const audioBuffer = await audioContext.decodeAudioData(arrayBuffer);

  const mp3Encoder = new lamejs.Mp3Encoder(2, audioBuffer.sampleRate, 128);
  const leftChannel = audioBuffer.getChannelData(0);
  const rightChannel = audioBuffer.getChannelData(1);
  const interleaved = interleave(leftChannel, rightChannel);
  const mp3Data = mp3Encoder.encodeBuffer(interleaved);
  mp3Data.push(...mp3Encoder.flush());

  const mp3Blob = new Blob([new Uint8Array(mp3Data)], { type: 'audio/mp3' });
  return mp3Blob;
}

function interleave(leftChannel, rightChannel) {
  const length = leftChannel.length + rightChannel.length;
  const result = new Float32Array(length);

  let inputIndex = 0;

  for (let outputIndex = 0; outputIndex < length; ) {
    result[outputIndex++] = leftChannel[inputIndex];
    result[outputIndex++] = rightChannel[inputIndex];
    inputIndex++;
  }

  return result;
}