static guessContentType_(mimeType, codecs) {
    const fullMimeType = shaka.util.MimeUtils.getFullType(mimeType, codecs);

    if (shaka.text.TextEngine.isTypeSupported(fullMimeType)) {
      // If it's supported by TextEngine, it's definitely text.
      // We don't check MediaSourceEngine, because that would report support
      // for platform-supported video and audio types as well.
      return shaka.util.ManifestParserUtils.ContentType.TEXT;
    }

    // Otherwise, just split the MIME type.  This handles video and audio
    // types well.
    return mimeType.split('/')[0];
  }
Guess the content type based on MIME type and codecs.

@param {string} mimeType
@param {string} codecs
@return {string}
@private