NEW YORK (Reuters) - MP3, a popular format for downloading music from the Web, is under pressure from leading technology companies such as Microsoft, the Wall Street Journal has reported.

Microsoft and Seattle-based RealNetworks are working to subtly wean consumers away from MP3 technology, encouraging them to use proprietary software formats instead, the paper said in its online edition on Thursday.

The technology companies, which have the music industry's blessing, are encouraging those who download music to use new proprietary software formats that make the audio sound significantly better but also make it harder to share copyright-protected songs, the paper said.

Microsoft, for example, plans to severely limit the quality of music that can be recorded as an MP3 file using software built into the next version of its personal-computer operating system, Windows XP, according to the report.

Music recorded in the software company's own format, called Windows Media Audio, will sound clearer and require far less storage space on a computer, the paper said.

Other formats gaining popularity are based on the relatively new Advanced Audio Codec created by AT&T, Dolby Laboratories, Sony and the Fraunhofer Institut Integrierte Schaltungen in Germany, the paper said.

MP3 is the format used to by controversial Internet music-sharing service Napster, whose operations have delighted consumers happy to access free music but infuriated the record industry.