将blob MIME类型设置为wav仍会导致webM [英] Setting blob MIME type to wav still results in webM

问题描述

我关注了这篇文章(直到第6步的代码)制作一个录音机，如下所示.生成audioBlob后，我调用一个自定义函数来上传blob.此功能适用于其他文件类型.

I followed this article (the code up to step 6) to make an audio recorder as below. After making the audioBlob, I call a custom function to upload the blob. This function works for other file types.

我将{ type: 'audio/wav' }传递给Blob构造函数.生成的文件确实假装为wave文件，可以在浏览器中正常播放，但不能在iOS上播放.我与 http://checkfiletype.com/进行了检查，发现文件实际上是WebM:

I pass { type: 'audio/wav' } to the Blob constructor. The resulting file indeed pretends to be a wave file, and would play fine in the browser, but not on iOS. I checked with http://checkfiletype.com/ and discovered the file was actually WebM:

如何确保文件实际上是.wav文件?

How do I ensure the file is in fact a .wav file?

该文章中编辑的代码:

navigator.mediaDevices.getUserMedia({ audio: true })
  .then(stream => {
    const mediaRecorder = new MediaRecorder(stream);
    mediaRecorder.start();

    const audioChunks = [];
    mediaRecorder.addEventListener("dataavailable", event => {
      audioChunks.push(event.data);
    });

    mediaRecorder.addEventListener("stop", () => {
      const audioBlob = new Blob(audioChunks, { type: 'audio/wav' });

      // Custom upload function
      uploadFile(audioBlob);
    });

    setTimeout(() => {
      mediaRecorder.stop();
    }, 3000);
  });

推荐答案

如何确保文件实际上是.wav文件?

How do I ensure the file is in fact a .wav file?

非常简单，我所知没有浏览器不支持原生导出到 wav .因此，您可以确定您的文件不是wav文件.

Quite easy, no browsers (I know of) does support exporting to wav natively. So you can be sure your file is not a wav file.

Blob构造函数的type选项仅表示浏览器应如何设置MIME类型以满足进一步的需求(例如何时将其发送到服务器). 但这实际上并不会更改您作为第一个参数传递的内容.

The type option of the Blob constructor only says the browser how it should set the MIME-type for further needs (e.g when it will send it to a server). But it doesn't actually change the content you passed as the first argument.

因此，它不会神奇地将您的webm文件转换为其他格式.

So it won't magically transform your webm file to an other format.

现在，您确实有一些选项更改MediaRecorder将其内容输出的格式，但是所支持的格式/编解码器取决于实现，而且我认为除 opus 之外，没有其他浏览器支持任何其他功能，在 webm 容器或 ogg *一个(仅* FF)中.

Now, you do have some options to change the format to which the MediaRecorder will output its content, but the set of supported formats / codecs is up to the implementations, and I don't think any browser supports anything else than opus, either in a webm container or in an ogg * one (* FF only).

[edit]:实际上是Chrome现在在webm中支持PCM .

感谢 isTypeSupported 方法，您可以很好地设置代码以使用这种格式(如果有的话)，但是我个人对此并没有太大的希望，并且会

Thanks to the isTypeSupported method, you can very well setup your code to use this format if it ever becomes available, but I personally wouldn't grow too much hope on this, and would look somewhere else if it is required to output a wav file...

const mime = ['audio/wav', 'audio/mpeg', 'audio/webm', 'audio/ogg']
  .filter(MediaRecorder.isTypeSupported)[0];
const recorder = new MediaRecorder(stream, {
  mimeType: mime
});

这篇关于将blob MIME类型设置为wav仍会导致webM的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！