Music sources and licenses
Buying XISA credit pays for the software and hosting. It does not take away the rights to copy, share, and adapt that the open licenses below already give you. The XISA player serves audio from the server without DRM, and does not place CC tracks inside an app package protected by platform DRM.
A work, a digital file, and a recording are different layers
A classical composition may be in the public domain, while a modern digital engraving, MIDI performance, recording, or sampled sound library can still carry its own rights. XISA keeps, for each track, the source URL, license version, download record, file hash, processing, and the license of the finished audio. “The composition is public domain” is not written down as “every digital file is free of copyright.”
Current sources
- Classical Piano MIDI Page. Performance MIDI by Bernd Krueger, from piano-midi.de, under CC BY-SA 3.0 Germany. XISA turns it into piano audio, converts the format, and masters it. The finished audio stays under the same license. Attribution does not mean the author endorses XISA.
- Mutopia Project. From mutopiaproject.org. Each digital score or MIDI has its own license. XISA accepts only items clearly marked Public Domain, CC BY, or CC BY-SA that allow commercial use, and keeps that exact license and editor credit in the per-track list. The guitar library currently uses Mutopia solo pieces only. Classical Guitar MIDI Archives is not used, because that MIDI copyright is not open.
Piano sounds
- Salamander Grand Piano V3+20200602, Yamaha C5, 16 velocity layers. By Alexander Holm, from FreePats, CC BY 3.0.
- YDP Grand Piano (fallback). Yamaha Disklavier Pro samples by Zenph Studios / OLPC, FreePats SoundFont, CC BY 3.0.
Guitar sounds
- University of Iowa MIS Raimundo 118, a nylon-string classical guitar. Played by Brian Penkrot on 11 December 2011 in the University of Iowa anechoic chamber, Earthworks QTC40. Three layers, pp / mf / ff, sampled by string. Source files are 24-bit / 96 kHz stereo. XISA downsamples them 2:1 to 48 kHz before rendering. Source: theremin.music.uiowa.edu/MISguitar.html. The studio states that these recordings may be used in any project, with no restrictions (MIS.html). XISA splits the chromatic takes into single notes, chooses the string by position, and hard-switches velocity layers, without a crossfade, so two pluck layers do not chorus into a plastic sound. The anechoic measurement microphones are bright, so mastering only adds a little body warmth and reduces air. It does not use the FreePats +9 dB Helmholtz boost.
License of the finished audio
Audio made from CC BY-SA MIDI or digital scores is released under the matching BY-SA version. Piano and guitar audio rendered from a public-domain source is offered at least under CC BY 3.0. XISA may interpret velocity, phrase the guitar, use pedal and rubato, render through a sound library, adjust loudness, convert formats, and cut structural excerpts. That does not imply that the original author, the editor, or the sound-library author endorses those changes.
After the library is published, the per-track list travels with the catalog: title, composer, maker of the digital file, original link, final license, and SHA-256. An entry without that evidence is not added to the playable library. Machine-readable list: licenses.json. Guitar library: listening samples. Per-track guitar list: guitar licenses.json. Per-track organ list: organ licenses.json.