看到这个答案,你可以从缓冲区创建一个音频 Wav 文件。
所以代码和方法可能是这样的:
方法:
// Convert a audio-buffer segment to a Blob using WAVE representation
// The returned Object URL can be set directly as a source for an Auido element.
// (C) Ken Fyrstenberg / MIT license
function bufferToWave(abuffer, offset, len) {
var numOfChan = abuffer.numberOfChannels,
length = len * numOfChan * 2 + 44,
buffer = new ArrayBuffer(length),
view = new DataView(buffer),
channels = [], i, sample,
pos = 0;
// write WAVE header
setUint32(0x46464952); // "RIFF"
setUint32(length - 8); // file length - 8
setUint32(0x45564157); // "WAVE"
setUint32(0x20746d66); // "fmt " chunk
setUint32(16); // length = 16
setUint16(1); // PCM (uncompressed)
setUint16(numOfChan);
setUint32(abuffer.sampleRate);
setUint32(abuffer.sampleRate * 2 * numOfChan); // avg. bytes/sec
setUint16(numOfChan * 2); // block-align
setUint16(16); // 16-bit (hardcoded in this demo)
setUint32(0x61746164); // "data" - chunk
setUint32(length - pos - 4); // chunk length
// write interleaved data
for(i = 0; i < abuffer.numberOfChannels; i++)
channels.push(abuffer.getChannelData(i));
while(pos < length) {
for(i = 0; i < numOfChan; i++) { // interleave channels
sample = Math.max(-1, Math.min(1, channels[i][offset])); // clamp
sample = (0.5 + sample < 0 ? sample * 32768 : sample * 32767)|0; // scale to 16-bit signed int
view.setInt16(pos, sample, true); // update data chunk
pos += 2;
}
offset++ // next source sample
}
// create Blob
return (URL || webkitURL).createObjectURL(new Blob([buffer], {type: "audio/wav"}));
function setUint16(data) {
view.setUint16(pos, data, true);
pos += 2;
}
function setUint32(data) {
view.setUint32(pos, data, true);
pos += 4;
}
}
用法:
let originalBuffer = bufferToWave(app.engine.wavesurfer.backend.buffer, 0, app.engine.wavesurfer.backend.buffer.length);