57 lines
3.3 KiB
Markdown
57 lines
3.3 KiB
Markdown
|
# Steinberg SDK integration (Phase 106)
|
||
|
|
|
||
|
|
The VST3 host uses Steinberg's pinned generated C ABI in the C99 core. Optional
|
||
|
|
SDK examples now also build against the full, separately supplied official C++
|
||
|
|
SDK and run Steinberg's validator. This adds an independent interoperability
|
||
|
|
check without adding a C++ runtime or network dependency to libxtc.
|
||
|
|
|
||
|
|
## Working integration
|
||
|
|
|
||
|
|
- Linux `.vst3` bundles resolve to
|
||
|
|
`Contents/<architecture>-linux/<bundle-stem>.so`. Direct `.so` paths still
|
||
|
|
work. The original chosen path remains the saved identity reference. This
|
||
|
|
supports conventional bundles, not arbitrary renamed modules or Windows DLLs.
|
||
|
|
- VST3 processing receives sample rate, absolute sample position, tempo and
|
||
|
|
musical position (`samples / rate * BPM / 60`). Position follows the existing
|
||
|
|
effect/instrument `_at` APIs, including seek. Tempo is the prepared plugin
|
||
|
|
spec's milli-BPM value; reprepare when it changes. Processing is marked playing
|
||
|
|
because this API represents active rendering, including offline rendering.
|
||
|
|
Loop, recording, wall-clock, time signature and continuous-time flags are not
|
||
|
|
asserted: the current plugin API does not carry that information. Positions
|
||
|
|
above `INT64_MAX` reject before processing, matching VST3's signed sample clock.
|
||
|
|
- Original SDK-built examples expose a mono half-gain effect and a mono,
|
||
|
|
16-channel sine instrument. The instrument handles note-on/off at their exact
|
||
|
|
block offsets; the host translates all-notes-off to held-note releases.
|
||
|
|
- The C render example demonstrates the actual xtc plugin facade and WAV writer,
|
||
|
|
including no-clobber output, without requiring JACK or a GUI.
|
||
|
|
|
||
|
|
See [the example instructions](../examples/steinberg/README.md) for SDK versions,
|
||
|
|
build commands, validation and ASIO diagnostics.
|
||
|
|
|
||
|
|
## ASIO and VST2 scope
|
||
|
|
|
||
|
|
ASIO is native driver I/O, separate from VST plugin hosting. The optional Windows
|
||
|
|
diagnostic enumerates drivers and inspects an explicitly selected driver's
|
||
|
|
channels, sample types, current sample rate, buffer bounds and reported latency.
|
||
|
|
It does not create/start audio buffers and is **not an xtc ASIO backend**.
|
||
|
|
The current xtc engine/backend still targets Linux/POSIX and JACK/PipeWire.
|
||
|
|
Windows portability, a C API platform bridge and native-driver qualification
|
||
|
|
are remaining Phase 106 work, not simulated by Linux tests.
|
||
|
|
|
||
|
|
VST2 support retains the existing original minimal ABI declarations. VST3's SDK
|
||
|
|
does not include the discontinued VST2 SDK. No VST2 SDK or user plugin is copied,
|
||
|
|
fetched or licensed by these build targets.
|
||
|
|
|
||
|
|
## Remaining work
|
||
|
|
|
||
|
|
The application VST3 adapter still accepts one mono input (or no audio input for
|
||
|
|
instruments), one mono output, float32 and zero reported latency. Its two mono
|
||
|
|
instances are not a native stereo plugin instance. It uses plugin defaults;
|
||
|
|
controller parameters, opaque-state persistence and custom editor windows remain
|
||
|
|
unimplemented in xtc. The SDK examples include an edit-controller class for
|
||
|
|
standard SDK-host compatibility; xtc does not instantiate it yet. The examples
|
||
|
|
have no editable parameters or opaque state, so they do not prove those paths.
|
||
|
|
No VST extension support or general third-party compatibility is inferred from
|
||
|
|
the validator passing these examples.
|
||
|
|
|
||
|
|
The complete acceptance checklist is in [Phase 106](ROADMAP.md#phase-106--steinberg-vst-sdk-and-asio-integration).
|