When you use CloudStor through your browser, you can play some audio files within CloudStor. However, the audio formats and codecs supported depend on the browser and operating system you’re using. For example, m4a files encoded in ALAC rather than AAC might only play on an Apple device with Apple Lossless Audio Codec available. But m4a files encoded in AAC will play on Apple and Windows devices.
Typically, Chrome, Firefox and Vivaldi will play all supported audio formats. MP3 files are most likely to be compatible with other browsers.