The popular file-hosting service 4shared has launched a new anti-piracy feature that scans shared files for copyright infringing content. The system, custom-built by the cyberlocker, scans for pirated music files based on a unique audio watermark. In the near future the site will also allow copyright holders to replace pirated files with links to sites where content can be bought legally.

As one of the largest file-sharing services online 4shared is closely watched by copyright holders who vigorously try to scrub pirated files from the site.

The file-hosting service offers a standard DMCA takedown procedure but recently decided to go a step further by developing its own content identification technology based on audio fingerprints.

Under the new system copyright holders can upload their files to 4shared’s backend. The company then makes a unique fingerprint of each file to prevent them from being shared in public by its users.

“4shared has always been a personal online file storage service and has never endorsed online piracy,” 4shared’s Mike Wilson tells TorrentFreak.

“So we have decided to introduce a music identification system, among the other steps, to maintain the reputation of a legitimate file storage and further prevent illegal usage of our service,” he adds.

4shared’s system is based on the open source solution Echoprint, which is powered by the music intelligence company Echo Nest. This technology allows 4shared to identify files based on audio characteristics instead of just a file hash.

“The algorithm calculates special code for each music file, based on its acoustic properties rather than on a digital hash code, thus making the code or ‘fingerprint’ a unique identifier of a certain title, no matter which properties or format the file has,” Wilson says.

When an attempt is made to share a pirated file in public it will be blocked, assuring copyright holders that their content won’t be distributed without permission. The system only scans public files meaning that it’s still possible for users to backup their own files privately.

The system 4shared has developed works in a similar way to YouTube’s Content ID system, which also offers filtering based on files copyright holders upload to the site.

4shared plans to expand the music identification system with an option to monetize pirated files in the future. This means that in addition to blocking pirated transfers, copyright holders will have an option to replace them with links to sites where the content can be bought legally.

“In the nearest future we will also provide a monetization option instead of simply blocking the file so the users can get the content in a legal way and the owners can make their profit,” Wilson told us.

Aside from audio files, 4shared can also offer similar services for video although these are expected to be rolled out at a later stage. For now, the company is focused on signing up content owners to its music identification account.