Guides / AcoustID
Recordings with multiple AcoustIDs
The recording "I Got You Babe" by Sonny & Cher has twenty-eight distinct AcoustIDs. This is almost assuredly a result of the huge variety of different releases the recording is listed as belonging to: the slightly different versions each appear on a different subset of the releases listed.
For that recording in particular, the difficult part is determining which tracks belong to which AcoustID. The only viable way to link them reliably is to acquire copies of the tracks which are definitively from each of those releases and use them to identify which recordings match each AcoustID and move the track to that recording.
Reading an AcoustID page
Take a look at Track "5502d840-500f-48a6-b64c-fb9780bb14a2" on AcoustID.
The first thing you see is a list of fingerprints. These are the slightly-different audio selections that were considered similar enough to get the same AcoustID. From there, you can select a couple of the fingerprints to compare how different a “same” fingerprint might be. Fingerprints #11831566 and #11185730 have the most submissions, so we'll set our focus there first. Open each in their own new browser tab and tile them, if possible, to be able to compare them easily.
- Two AcoustID fingerprints of 'I Got You Babe'
The vertical axis in these visual representations always represents time. The entire bar represents two (2) minutes (or one minute, in the case of much older fingerprints), so each vertical pixel is but a very brief moment.
With both of those fingerprints in front of you, it's easy to see that the differences between them are very small: only a slight vertical offset, plus the occasional single pixel variance.
Merging AcoustIDs
Continuing the example from above, let's look at an AcoustID for Track "b7b0e619-f0fc-4275-b7d5-15577fe41e97" that could be from the same recording. One of its most-submitted fingerprints is #21014712. Comparing it to the two from above it's quick to see that they are practically the same.
- The two AcoustIDs from above with a new one between them
This new AcoustID is probably okay to merge.
Further down on the AcoustID page you can see a list of recordings which have this AcoustID. In general, it is safe to merge recordings which have the same AcoustID as long as they each only have the same AcoustID and no others. If they each have multiple AcoustIDs, it's probably because some releases have a different recording and someone chose wrong. Also, be mindful of different performance relationshipss and ISRCs, though liner notes and the various ISRC sources have been known to be wrong, as well.
When not to merge
If we now compare the two original fingerprints with Track "fd3a066b-5f20-46ec-ae73-3c7a6900802d", from an entirely different release (Buster: The Original Motion Picture Soundtrack), we might see more differences. The most-commonly submitted fingerprint for the soundtrack is #11993528, so let’s look at that now.
- The two original AcoustIDs with the one from the Buster soundtrack between them
Indeed, comparing this new AcoustID to either one from above quickly reveals some substantial differences. While they are similar enough to conclude that it is probably the same song (the general shapes present and their arrangements are mostly the same), but with sufficient variances to conclude they are almost certainly from a different recording in some way. Of course, there’s no way to tell from only viewing the fingerprints exactly what the differences are; for that, we'd need to listen to the files they were generated from.
Problems
There are a few places where AcoustID has trouble.
False positives
The following types of recordings are prone to producing incorrect matches:
- Karaoke versions
- Instrumental versions
- Radio edits (where only a small amount is edited, bleeped out, etc.)
- Any recordings which only diverge after the two-minute mark where the acoustID fingerprint ends[1]
- Very short (15–30 seconds) tracks that produce too small of a sample size
False negatives
A time shift of more than a handful of seconds will often cause a different AcoustID to be assigned.
It is also worth noting that recordings that differ by more than seven seconds in length[2] will always be given a different AcoustID, even if the the shorter fingerprint is identical to a section of the longer one. If you see an AcoustID with a track attached of a different length greater than that, it always indicates something is wrong, whether the recording duration, and also recordings from two releases that shouldn’t have used the same recording.)
Useful tools
While the central tool for working with AcoustIDs is the fpcalc executable from the chromaprint project, other applications can also be quite useful when dealing with AcoustIDs and linking them to MusicBrainz entities.
Web browsers
One of the most useful capabilities to have when comparing AcoustID fingerprints' visual representations on acoustid.org is the ability to view multiple browser tabs next to each other at the same time rather than having to switch between them, a behavior known as "tiling." While the feature can be found in some mainstream web browsers circa 2023 (Microsoft Edge introduced vertical tiling at that time under the name "Split screen"), the Vivaldi Browser has offered the feature since 2021 and their implementations is objectively more robust. Browsers that are known to provide at least some form of tab tiling are listed below.
Stable projects
- Arc (horizontal/vertical tiling present since 2024 as "Split View,"[3] based on the Blink browser engine from Chromium and available for Windows and macOS)
- Floorp (vertical tiling present since 2024 as "Split View," based on the Gecko and SpiderMonkey browser engines from Mozilla and available for Windows, macOS and Linux)
- Vivaldi Browser (horizontal/vertical/grid tiling present since 2021,[4] based on the Blink browser engine from Chromium and available for Windows, macOS, Linux, Android and iOS)
- Zen Browser (horizontal/vertical tiling present since 2024 as "Split View,"[5] based on the Blink browser engine from Chromium)
Public previews
- Split Browser (downloads available for Windows and instructions provided for compilation from source code on macOS and Linux)
- Stack
Image comparison tools
An assortment of software exists to aid in image comparison, including desktop applications, web services and lower level libraries for interpreted languages like Python. These can all be used to quantitatively analyze the visual representation of fingerprints available on AcoustID.org with varying levels of effectiveness.
References
- ↑ File: fpcalc.cpp, line 21, chromaprint repository on GitHub, introduced in Commit 3513f22: "Simplify fpcmp" on August 17, 2011 by Lukáš Lalinský. First released in Chromaprint v1.4. Archived by the Wayback Machine on July 23, 2025. Last accessed on July 23, 2025.
- ↑ File: const.py, line 19, acoustid-server repository on GitHub, introduced in Commit 8f5cdba: "Better way to import submissions". First released in AcoustID Server v25.2.0. Archived by the Wayback Machine on July 23, 2025. Last accessed on July 23, 2025.
- ↑ "Split View: View Multiple Tabs at Once" on Arc Help Center. Archived by the Wayback Machine on May 20, 2024. Last accessed on July 22, 2025.
- ↑ "Tab Tiling in Vivaldi" on Vivaldi Browser Help. Archived by the Wayback Machine on February 22, 2024. Last accessed on July 22, 2025.
- ↑ "Split View" on Zen Browser User Manual. Archived by the Wayback Machine on April 24, 2025. Last accessed on July 22, 2025.
External links
- "How does Chromaprint work?" written by its developer, Lukáš Lalinský
- Web browsers:
How-To Pages | |
---|---|
Introductory Guides | Beginners' Guide · Creating an Account · Editing · Voting · Writing Edit Notes |
Basic How-Tos | Adding an Artist · Adding Relationships · Using the Relationship Editor · Using Artist Credits · Adding a Release · Works · Events · Places · Series · Instruments · Areas |
Specific How-Tos | Merging Releases · Merging Recordings · Removing Entities · Adding Cover Art · Identifying Labels · Splitting Artists · Adding Standalone Recordings · Adding Disc IDs · Cancelling Edits · Searching for Edits · Reporting a User · Reporting an Issue · Working with AcoustIDs · Tagging Files with Picard |