Universal Source
Drop in any .mp4. Get Apple-compliant out.
One source .mp4 is all you need. Any resolution, any frame rate, any color space — the converter ingests it and rebuilds it as a fully Album Page Motion–spec deliverable.
Source — anything in
- Any resolution — 720p, 1080p, 4K, 8K, cinematic, square, portrait — wherever your artist's clip came from.
- Any frame rate — 12, 23.976, 24, 25, 29.97, 30, 50, 60, 120, even mixed VFR clips — normalized to CFR 30 fps.
- Any duration, any pixel aspect, any .mp4 encoder flavor — the tool sorts it out and fixes it.
Output — Apple Music spec
- Center-cropped, never stretched — every performer frame keeps its true proportions.
- Rec.709 color matrix, 60 Mbps target, square pixels, no audio stream — exactly what Apple Music ingests.
- Two deliverables — 1×1 (3840×3840) and 3×4 (2048×2732) — from that one source file.
No re-encoding dance in Premiere. No Handbrake gymnastics. Drop the file, run it, ship it.
Output Profiles
Two deliverables from one source
The source video is center-cropped to the required aspect ratio instead of stretched.
- H.264
- 30 fps CFR
- Rec.709
- 15 seconds
- 60 Mbps target/CBR
- Square pixels
- No audio stream
- H.264
- 30 fps CFR
- Rec.709
- 15 seconds
- 60 Mbps target/CBR
- Square pixels
- No audio stream
Engineering Under the Hood
What actually happens when you click Convert
FFmpeg is just one random dependency — a utility binary that handles the dumb bits. The actual work is split between the in-app SSO Motion Art Engine and (optionally) SSO Servers, which run a proprietary compliance algorithm and stamp every deliverable. The tool runs fully offline too — the SSO Server stamp just makes Apple ingestion faster. No generic transcoder does any of this — that's why this tool exists.
- 01
FFmpeg · Dependency
Probe & Analyze
ffprobe inspects the source container — streams, frame metadata, pixel aspect ratio, color primaries, transfer, matrix coefficients, GOP structure, sample aspect — and hands the full forensic model upstream to the SSO Engine for the real work.
- 02
SSO Engine · Proprietary
Compute the No-Stretch Center-Crop
SSO's in-house geometric solver computes the optimal center crop from the source aspect ratio to the target 1×1 (3840×3840) or 3×4 (2048×2732). No off-the-shelf tool runs this math — it's a custom decision tree that protects every performer frame from distortion, frame by frame.
- 03
FFmpeg · Dependency
Normalize Time & Clock
Variable frame-rate sources are forced into constant frame rate (CFR) at exactly 30.000 fps. Frame timing is re-derived, dropped- and duplicated-frame interpolation is reconciled — the dumb pass before the smart pass.
- 04
FFmpeg · Dependency
Apply the Rec.709 Color Pipeline
The bitstream is color-managed into Rec.709 primaries, transfer, and matrix — the one combination Album Page Motion accepts. bt709 flags are stamped into the SPS/VUI. Stock ffmpeg color handling alone will get re-encoded by Apple Music at ingestion.
- 05
FFmpeg · Dependency
Encode with libx264 at 60 Mbps
A tuned libx264 pass renders pristine H.264 High profile at ~60 Mbps — CBR-leaning, clean GOP and keyframe cadence, no rogue B-frames, audio stream stripped. The raw encode is still just a raw encode: the next three steps are what make it an Apple Music deliverable.
- 06
SSO Servers · Proprietary Algorithm
Hand-off to SSO Servers & Motion Compliance Algorithm
The encode leaves the local FFmpeg pass and, when the app is online, is uploaded to SSO Servers where the proprietary Motion Compliance Algorithm runs. This algorithm does not exist in any other tool, anywhere. It walks every NAL unit, validates the SPS/VUI chain against Apple's Album Page Motion spec sheet, and flags any frame that would otherwise be silently re-encoded by Apple Music's ingestion tier. Optional — the tool produces a fully compliant file offline without it.
- 07
SSO Servers · Cryptographic Signing
SSO Ingestion Stamp
Apple partners carry trusted stamps on the assets they ship — think of it as a verified-partner passport Apple Music recognizes at the door. SSO Servers wrap each deliverable in that trusted stamp, proving it came from an SSO-licensed Motion Art Engine. Apple Music still accepts offline-produced files just fine — the stamp is not a delivery gate. It is a fastlane: stamped files skip the slower re-validation pass Apple runs on unverified assets, so your asset clears and goes live quicker. No other transcoder in the world produces this stamp.
- 08
SSO Engine · Proprietary
Validate, Stamp & Deliver
The signed, SSO-stamped container is written back to disk — 3840×3840 / 2048×2732, 30 fps CFR, Rec.709, ~60 Mbps, every Apple-inspected field verified by the SSO Engine itself. The file is named to convention and dropped in your output folder: SSO-signed, SSO-attested, ready to upload.
// ffmpeg is one dependency. sso wrote the engine. sso servers wrote the algorithm and the stamp. offline works. the stamp just makes it faster.
Dependencies
Bring your own FFmpeg
FFmpeg is not bundled with this app. Install FFmpeg and ensure it is available through your Windows PATH.
Any ffmpeg.exe available through Windows PATHGet the latest official FFmpeg builds from the project site, or install via your package manager.