screencastgen

Provider Overview

How the pluggable provider registries work.

Source: screencastgen/providers/

Registry Pattern

screencastgen uses registry/factory patterns for TTS, alignment, lip-sync, and visualization providers. ML-heavy backends are lazily imported, so provider modules are only loaded when the backend is actually created.

flowchart TB
    CLI[CLI and server arguments] --> Registries
    Pipelines --> Registries

    subgraph Registries[Lazy provider selection]
        TTS[TTS registry]
        Align[Alignment registry]
        Lip[Lip-sync registry]
        Visual[Visualization factory]
    end

    TTS --> Qwen[Qwen3-TTS]
    TTS --> Remote[Remote TTS]
    Align --> WhisperX
    Lip --> LatentSync
    Visual --> ManimGL
    Visual --> ManimCE

How It Works

TTS, alignment, and lip-sync providers define specs with metadata such as name, module path, class/function name, capabilities, and extra parser args.
The registry module stores name -> spec; visualization currently uses a direct factory with the same named-provider shape.
create_backend(name) or the equivalent registry helper imports or instantiates the provider only when needed.
Parser helpers register backend-specific CLI or server arguments by context.

This keeps screencastgen --help usable without requiring ML dependencies to be installed.

Provider Types

TTS Backends

Implement the TTSBackend protocol and are registered in TTS Registry.

Backend	Class	Contexts	Key Capability
Qwen Backend	`QwenTTS`	`cli`, `server`	Multi-language TTS and batched server synthesis
Remote TTS	`RemoteTTS`	`cli`	HTTP proxy to GPU server

Alignment Providers

Registered in Alignment Registry.

Provider	Function	Description
WhisperX Provider	`align_with_whisperx()`	Word-level alignment via WhisperX

Lipsync Providers

Registered in Lipsync Registry.

Provider	Function	Description
LatentSync Provider	`run_latentsync()`	High-quality lip-sync

Visualization Renderers

Registered in Visualization Registry.

Renderer	Class	Description
ManimGL Renderer	`ManimGLRenderer`	Primary ManimGL subprocess adapter
ManimCE Renderer	`ManimCERenderer`	Command builder placeholder; rendering intentionally disabled