Microsoft will now allow Xbox Music users to store their local MP3 tracks to their OneDrive cloud storage account. This will allow users to play their music on the Xbox Music app for Windows 8.1 and Windows Phone 8.1, along with the Xbox 360 and Xbox One consoles and on the Xbox Music website.
In addition to MP3 tracks, this new service also supports audio files in M4A (AAC), and WMA formats. Microsoft says that this service is for any Xbox Music user and not just ones that have an Xbox Music Pass subscription. However, Microsoft says those subscribers will get something extra with this new feature: "100 GB of additional storage in OneDrive to save all the music you love." The service does require an Xbox Live account.
This service is available in the US, along with Argentina, Australia, Austria, Belgium, Brazil, Canada, Denmark, Finland, France, Germany, Ireland, Italy, Mexico, Netherlands, New Zealand, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. There is an upper limit of 50,000 songs that can be stored. iOS and Android Xbox Music app users won't be able to play songs stored on OneDrive.
Source: Xbox Music