Feature Flags

This document describes the available feature flags for the rustsynth crate. Feature flags allow you to enable optional functionality and control which parts of the VapourSynth API are available.

Data Type Features

f16-pixel-type

Enables support for 16-bit floating-point pixel components using the half::f16 type from the half crate.

When enabled, allows working with video formats that use 2-byte floating-point samples. This is useful for high-precision video processing workflows.

Dependencies: half crate

proc-macro

Enables procedural macro support by including the rustsynth-derive crate.

This feature provides derive macros and other procedural macros to simplify filter development and reduce boilerplate code.

Dependencies: rustsynth-derive crate

Linking Features

These features control which VapourSynth libraries are linked at build time.

vapoursynth-functions

Links to the main VapourSynth functions library. This is required for most core VapourSynth functionality including creating cores, working with nodes, and processing frames.

Default: Enabled

vsscript-functions

Links to the VSScript functions library, which enables script evaluation and higher-level VapourSynth scripting functionality.

When enabled, the vsscript module becomes available with functions for evaluating VapourSynth scripts.

Default: Enabled

API Version Features

These features control which versions of the VapourSynth API are available.

api-41

Enables VapourSynth API version 4.1 headers and functionality.

Provides access to:

• CoreRef::clear_cache() - Clears all caches associated with the core
• Node::clear_cache() - Clears all cached frames for a specific node
• RequestPattern::FrameReuseLastOnly - Advanced frame reuse pattern for filters

Default: Enabled

script-api-42

Enables VSScript API version 4.2 headers and functionality.

Provides access to:

• ScriptAPI::get_available_output_nodes() - Get available output nodes from a script
• Enhanced VSScript environment functionality for listing output indices

Default: Enabled

graph-api

Enables the experimental VapourSynth Graph API.

This is an unstable/experimental feature that provides access to:

• Node::get_creation_function_name() - Retrieve the function name used to create a node
• Advanced debugging and introspection capabilities

Note: This API is experimental and may change or be removed in future VapourSynth versions.

Default Features

The following features are enabled by default:

• vapoursynth-functions
• vsscript-functions
• api-41
• script-api-42

Usage

To use specific features in your Cargo.toml:

# Enable only core functionality
rustsynth = { version = "0.6", default-features = false, features = ["vapoursynth-functions"] }

# Enable all features including experimental ones
rustsynth = { version = "0.6", features = ["f16-pixel-type", "proc-macro", "graph-api"] }

# Custom feature combination
rustsynth = { version = "0.6", default-features = false, features = [
    "vapoursynth-functions",
    "vsscript-functions",
    "api-41",
    "f16-pixel-type"
] }