How does 3vise work?

3vise is a macOS front-end GUI for MP3val, an open source command line tool that identifies and repairs errors in the .mp3 file container that stores the listenable audio stream. Often times, the audio stream itself is not damaged, but the information defining the mp3 file (surrounding the audio stream) can have problems for one reason or another. According to MP3val’s documentation on sourceforge, MP3val is:

“…a small, high-speed tool for MPEG audio files validation and (optionally) fixing problems. It was primarily designed for verification of MPEG 1 Layer III (MP3) files, but supports also other MPEG versions and layers. It can be useful for finding corrupted files (e.g. incompletely downloaded).

MPEG is a streamable format, that is, it is optimized for quick and easy recovery from errors. MP3 decoders are very tolerant to inconsistencies in the input file. Most players even don’t report to user about stream errors. So, as a rule, user doesn’t know whether his files are valid or broken. But using broken files can eventually lead to problems during playback on certain software/hardware.

MP3val can assure you that your files are consistent in the terms of MPEG frames, that is, it ensures that the file can be easily split into the frames and doesn’t contain garbage. It checks also some other issues, such as track length stored in the VBR header. Checking by MP3val isn’t a full test for compliance with existing formal and informal standards. MP3val neither decodes audio data nor checks for data validity in the frame.

MP3val can also fix most of the problems. Be careful: although MP3val can repair even files with MPEG stream errors, it is recommended that you find a “good” copy of this file, because a “click” sound usually can’t be removed, the repaired file will only look like good.”

By bringing MP3val into a graphical user interface for macOS users on systems 10.12 Sierra – 11.0 Big Sur, cflo inc. has provided a contemporary solution to users with large collections of mp3 files that want to clean their data to get rid of these hidden and mysterious errors. Distributing the 3vise app for free ensures that MP3val can reach as many users as possible and make this excellent tool accessible to users who otherwise would not have the access or technical know-how to install a command-line version.

Does 3vise do anything else?


Not only does 3vise allow users to scan and repair their files using MP3val’s process, it also contains the option to strip ID3 metadata from the files in various sets. With two distinct targets (defined by the user’s preferences in Settings) you can optionally remove ID3 tags generated by Serato Scratch Live / Serato DJ Pro (aka GEOB fields) OR remove “All” ID3 fields (a process that in fact retains only the Title, Album, Artist, and Comment fields).

In 3vise this option is labeled “Scrub Metadata” and by choosing this option on the main screen, the entire function of the app changes. This means that if the user conducts a “Scan and Repair” process with the “Scrub Metadata” option turned OFF, the file list is processed using MP3val. If the “Scrub Metadata” option is turned ON, the file list has it’s ID3 info stripped according to the user’s Settings (Serato vs All).

The reason for these two distinct processes is that Serato DJ Pro app can label songs as “corrupt” for multiple different reasons. Some songs will be show as corrupt for having issues with the mp3 container (fixable with MP3val process) and some will be corrupt for having invalid or mismatching GEOB data (fixable by removing the Serato-specific metadata), while others may have invalid data stored in innocuous fields such as Genre, Track Number, or Album Artwork (fixable by removing “All” metadata). It is for this reason that we recommend running your corrupt files through 3vise in stages: First with “Scrub Metadata” turned off, then remove the files that were fixed successfully, and run it again with “Scrub Metadata” turned on targetting Serato metadata. After re-analyzing all of your files that were once marked as “corrupt”, run any remaining files through one last time with “Scrub Metadata turned on, this time targeting “All”.

Please note that some songs will continue to be marked as corrupt, even after the 3vise Scan and Repair process. Some songs are truly corrupt in ways that 3vise cannot account for. We will issue updates to 3vise in order to add new ways to identify and fix files with corrupted containers or metadata but that still have intact audio streams… leading to a better library for DJs everywhere, and a peace of mind that you are performing with the best possible tools at your disposal!