Pymss vs StemSplit

Pymss is an open-source music source-separation toolchain that runs on the user's own machine and separates audio into vocals, drums, bass, and other stems. Its Studio desktop workspace handles model management, batch jobs, and stem editing. Users can import files or folders, choose a downloaded model, configure inference, and queue work. Studio can browse, download, resume, and delete model files, with storage cleanup controls. Waveform previews, mix controls, saved projects, and stem export support work on the results. Pymss can chain models so each workflow step uses the preceding step's output. The inference package lists WAV, FLAC, MP3, M4A, AAC, Opus, Vorbis, and Ogg output. Other components include ComfyUI custom nodes, a VST3 ARA plugin for compatible DAWs, and a browser interface bundled with the server. The ARA plugin provides per-stem mute and solo controls; its README gives Reaper and Studio One as host examples. The repositories have separate licenses: Studio is listed under AGPL-3.0 and the inference package under MIT. Studio remains at an early development stage, and changes between versions may break things.

StemSplit separates songs into vocals, instrumentals, and other stems for karaoke, music production, and audio editing. It offers four-stem separation and a six-stem mode that additionally separates guitar and piano. Users can upload MP3, WAV, FLAC, M4A, OGG, WEBM, AAC, OPUS, AIFF, AIF, or WMA files up to 100 MB, or submit YouTube and SoundCloud URLs. Batch processing is supported, with MP3, WAV, and FLAC exports. The service says most tracks finish in under a minute and advertises separation accuracy above 95%. It runs on the web, through a Chrome extension, and via a REST API with webhooks. Credit packages include API access and do not expire: Starter costs $2, paid once for 10 minutes, Standard $5, paid once for 30 minutes, Pro $12, paid once for 100 minutes, and Studio $30, paid once for 300 minutes. A free plan and free trial are listed.