static getFullOrConvertedType(mimeType, codecs, contentType) {
    const MimeUtils = shaka.util.MimeUtils;
    const fullMimeType = MimeUtils.getFullType(mimeType, codecs);
    const fullMimeTypeWithAllCodecs = MimeUtils.getFullTypeWithAllCodecs(
        mimeType, codecs);
    const ContentType = shaka.util.ManifestParserUtils.ContentType;
    const TransmuxerEngine = shaka.transmuxer.TransmuxerEngine;

    if (TransmuxerEngine.isSupported(fullMimeTypeWithAllCodecs, contentType)) {
      return TransmuxerEngine.convertCodecs(
          contentType, fullMimeTypeWithAllCodecs);
    } else if (mimeType != 'video/mp2t' && contentType == ContentType.AUDIO) {
      // video/mp2t is the correct mime type for TS audio, so only replace the
      // word "video" with "audio" for non-TS audio content.
      return fullMimeType.replace('video', 'audio');
    }
    return fullMimeType;
  }
Takes a MIME type and a codecs string and produces the full MIME
type. If it's a transport stream, convert its codecs to MP4 codecs.
Otherwise for multiplexed content, convert the video MIME types to
their audio equivalents if the content type is audio.

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