Comparison · Open source vs API
Source Separation API vs Self-Hosted Demucs
Demucs is the open-source quality standard, and self-hosting it is a real engineering project. This is the honest cost comparison — quality, GPUs, ops, and when each choice makes sense.
What self-hosting Demucs really is
Demucs/HTDemucs is an excellent model. Running it in production means: GPU capacity, CUDA/PyTorch environment management, model checkpoints, a job queue with retries, monitoring, and keeping the model current. Each of those is a project; together they are a team.
Side by side
| Self-hosted Demucs | mlslabs API | |
|---|---|---|
| Quality | State of the art | Same model family, per-mode tuning |
| GPU cost | Fixed monthly, idle included | $0 — per minute of audio |
| Throughput | One GPU lane per queue | Elastic parallel workers |
| Ops burden | Queue, retries, monitoring, updates | None |
| Data control | Fully on-prem | Object storage in/out |
| Batch | You build it | Native + webhooks |
The quality question
Both use HTDemucs-class models; quality differences come from tuning, not the base engine. Our modes are tuned per workload (music vs speech), which is the variable that matters most for real results. A/B on your own audio before choosing.
Decision rules
- Data must never leave your environment → self-host
- Existing idle GPU fleet → self-host
- Product feature, variable volume → API
- No GPU ops team → API
- Bursty batch jobs (karaoke, remix, catalog) → API
FAQ
Common questions
Is the API as good as Demucs?
Same model family with per-mode tuning — run a blind A/B on your files. Most teams find API quality at least equal, with far less operations.
What does a self-hosted GPU cost?
A rented GPU for continuous separation runs hundreds per month before your engineering time. The API bills per minute of audio, so idle costs zero.
Can I process a full catalog?
Yes — that is the API's designed workload: submit N jobs, collect N webhooks, pay per audio minute.
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