Planning a 1,000-Track Catalog Conversion to Immersive Audio
Spatial9 Team · · 8 min read
Key takeaways
- Start with an inventory of every recording and open the actual files: folder names and labels are not proof of what exists.
- Triage each track by source: an existing ADM master, multitracks or stems, stereo only, or missing. Each tier needs a different route.
- Apple Music does not accept Dolby Atmos made by upmixing or extracting stems from a stereo release, so check platform rules per tier before scheduling.
- Run a pilot batch across tiers, then use a QC plan with automated checks on every file and a full listening sample per batch.
- Budget and time should come from your own pilot measurements, not from throughput claims.
- Tracks with existing ADM masters convert to Eclipsa Audio with the free ADM to Eclipsa converter; the Spatializer API and a studio partnership support larger programmes.
A label or publisher with a thousand tracks rarely has a thousand identical files. Some songs already have a Dolby Atmos mix sitting in an archive. Some have full multitracks. Many exist only as a stereo master, and a few have missing or mislabelled files. Each group needs a different route, and some routes are not accepted by every platform. This guide walks through the plan step by step.
Step 1: build the inventory
Start with one spreadsheet, one row per recording. The columns that matter most:
| Column | Why it matters |
|---|---|
| ISRC, title, artist, version | Identifies the recording and catches duplicates |
| Release and label or owner | Tells you who must approve |
| Stereo master location and format | Every route needs it as a reference |
| Multitracks or stems available | Decides which route is possible |
| Existing immersive master | ADM BWF, surround or none |
| Sample rate and bit depth | Flags files that need attention |
| Rights status for immersive | Blocks work until it is clear |
| Target platforms | Decides the formats to produce |
| Priority and batch | Drives the schedule |
Do not trust folder names. A file called "Atmos" may be stereo, and a folder of "stems" may hold a single bounce. Open the actual files.
Step 2: triage by source material
Sort every row into one tier. The free Spatial9 file checker helps here: it reads more than 50 formats in your browser without uploading anything, and tells you whether a file is an ADM master, a surround mix, an encoded delivery file, stereo or mono. For what each signal means, see Is this file really immersive?
| Tier | What exists | Route |
|---|---|---|
| A | ADM BWF master from an existing Dolby Atmos mix | Convert to Eclipsa Audio for YouTube with the free ADM to Eclipsa converter |
| B | Multitracks or stems from the original session | New immersive mix by an engineer, or stems through the Spatializer |
| C | Stereo master only | Spatializer for Music separates the instruments and places them in 3D, for platforms that accept this route |
| D | Missing, damaged or unclear files | Locate sources or park the track |
Tier A is usually the quickest win: the creative work is done and you are changing the delivery format. Our guide to converting Dolby Atmos to Eclipsa Audio explains what the conversion keeps.
Tier B and C differ in kind, not just effort. The trade-offs are explained in upmixing stereo vs mixing from stems and how to create spatial audio from stereo.
Step 3: rights and platform rules
Before a single track is processed, confirm two things for each tier.
Rights. Check that the owner can authorise a new immersive version, whether artist or producer approval is needed, and who signs off on the result. Record the answer in the inventory.
Platform rules. These depend on the source, so read them per tier:
- Apple Music states that Dolby Atmos files generated from stereo mixes are not allowed. Its guidance specifically rules out upmixing from a stereo release and extracting stems from a stereo release, and requires a Dolby Atmos track to be created from multitracks or from stems made from multitracks. Tier C tracks are therefore not candidates for Apple Music Dolby Atmos.
- Apple Music also requires a unique secondary ISRC for Dolby Atmos deliveries, and Dolby Atmos can only be delivered through Transporter or an approved distributor or encoding house.
- YouTube lists Eclipsa Audio among its recommended upload codecs, as a "Stereo + Eclipsa Audio" option in a video MP4 at 48 kHz.
- Labels and other services publish their own specs. UMG's Dolby Atmos spec, for example, requires ADM BWF, 24-bit, 48 kHz (96 kHz only when the mix was created at 96 kHz), and a duration matched to the stereo asset.
Spatializer for Music exports Eclipsa Audio for YouTube and Dolby Atmos for Apple Music, Amazon Music and Tidal, but the source still decides eligibility. Check each service's current policy for the tier before you schedule deliveries.
Step 4: prioritise
With tiers and rights in place, rank the catalog. Useful criteria, none of which need outside data:
- Readiness: Tier A and cleared Tier B tracks first.
- Business value: the tracks your own streaming reports show people play, plus anything with an upcoming release, anniversary, sync or campaign.
- Grouping: whole albums together, so album-level presentation and sequencing stay consistent.
- Risk: park disputed or Tier D tracks rather than letting them block a batch.
Step 5: a pilot batch and a QC sampling plan
Pick a pilot of a few dozen tracks that spans every tier, genre and decade in the catalog. Run them through the full chain, from source to delivered file, and record how long each stage took and what went wrong.
Then write the QC plan for the main run:
- Every file: an automated structural and loudness check. Confirm the format, channel count and layout, sample rate and length, and run ITU-R BS.1770 integrated loudness and true peak. Dolby's music delivery playbook and UMG both give -18 LKFS integrated and -1 dBTP true peak as maximums for Dolby Atmos music.
- A listening sample: a full listen on a set share of each batch, on speakers and headphones, plus every track the automated check flags.
- Escalation rules: if a batch sample fails, widen the sample for that batch or review it fully.
- Sign-off: who approves each batch, and where that decision is recorded.
The file checker can do the structural pass and a BS.1770 loudness, true-peak and clipping check on your device, and plays immersive files in a virtual 7.1.4 room for listening checks. It is a QC aid, not a certified meter.
Step 6: naming and metadata
Decide the naming scheme before the first export, and never change it mid-project. Include the ISRC or catalog number, the version and the format in every name, for example USABC2600001_Main_IAMF_48k.mp4. Keep the secondary ISRC for each immersive version in the inventory, next to the stereo ISRC, and write a notes file per album with rates, channel order, loudness figures and approvals.
Step 7: delivery to distributors
Group deliveries by destination, not by batch. Each distributor or platform has its own ingestion route and spec: Apple Music through Transporter or an approved partner, YouTube through uploads or a content management workflow, labels through their own portals. Keep a delivery log per track with the date, the destination, the file sent and the response, so rejections can be fixed quickly.
Budget and time without guesswork
Do not plan from a headline throughput number, including ours. Build the plan from the pilot:
- List the stages: inventory, triage, rights, processing or mixing, QC, fixes, metadata, delivery.
- Record what each pilot track actually took at every stage, per tier.
- Multiply by the number of tracks in each tier, then add a contingency for Tier D and for rejections.
Processing is only one line in that plan. Spatializer for Music typically takes 2 to 5 minutes per song, but listening review, fixes, approvals and metadata all need people, and the pilot is the only honest way to size them.
Tools for a catalog project
- The Spatializer API at /api lets you convert many songs in a scripted pipeline instead of one by one.
- A studio partnership at /for/studios is for labels and studios planning immersive releases at scale with our team.
- The free ADM to Eclipsa converter at /adm-to-eclipsa handles Tier A tracks that already have a Dolby Atmos ADM master.
- The free file checker at /try-your-files covers triage and QC sampling.
Scope of this guide
This is a planning framework, not legal advice or a platform specification. Platform rules change, so confirm each one at the time of delivery. We make no claims here about processing speed at catalog scale or about how converted tracks will perform.
Frequently asked questions
Can stereo-only tracks go to Apple Music in Dolby Atmos?
Not under Apple's published guidance, which rules out Dolby Atmos made by upmixing or by extracting stems from a stereo release. For those tracks, look at platforms whose rules allow the route, such as YouTube with Eclipsa Audio, and check each policy first.
Where should a catalog conversion start?
With tracks that already have an ADM master. They convert to Eclipsa Audio without a remix, and the free converter costs nothing to try.
How many tracks should we listen to in full?
Set a share per batch in your QC plan, listen to every flagged track, and widen the sample when a batch fails. Your pilot shows where problems cluster.
Do we need new ISRCs?
For Apple Music Dolby Atmos, yes: Apple requires a unique secondary ISRC. Check every other destination's rules too.
Sources
- Delivering Dolby Atmos audio, Apple Music Provider Support.
- YouTube recommended upload encoding settings, YouTube Help.
- Immersive Audio Model and Formats (IAMF) specification, Alliance for Open Media.
- Dolby Atmos Music Delivery Playbook, Dolby Laboratories.
- Dolby Atmos Audio Servicing Asset Specifications, UMG Content Guide.
- ITU-R BS.2076: Audio Definition Model, International Telecommunication Union.
- ITU-R BS.2088: Long-form file format for the international exchange of audio programme materials with metadata (BW64), International Telecommunication Union.
- ITU-R BS.1770: Algorithms to measure audio programme loudness and true-peak audio level, International Telecommunication Union.
From catalog to every screen
A thousand tracks is a project, not a button. Plan it in tiers, prove it with a pilot, and Spatial9 can help with the API, the free converter and a studio partnership.
Dolby and Dolby Atmos are trademarks of Dolby Laboratories. Spatial9 is not affiliated with or endorsed by Dolby Laboratories.