AviSynth Pascal

AviSynth Pascal refers to using the Pascal programming language (via Delphi or Free Pascal / Lazarus) to interact with AviSynth—a powerful script-driven text video frame-server.

While AviSynth’s core engine and official plugins are natively written in C++, developers use Pascal to either write external video processing plugins or embed AviSynth frameserver capabilities directly into Delphi/Pascal multimedia applications. 🛠️ How it Works: The AviSynth C API

AviSynth’s native C++ architecture relies heavily on C++ classes and virtual methods (IClip), which do not translate cleanly to Pascal binary standards (ABI). To bridge this gap, developers use the AviSynth C API via headers like avisynth_c.h.

In the Pascal world, this header is translated into a header file usually named avisynth_c.pas. This file converts C-compatible pointers, structures, and function callbacks into native Delphi/Pascal code. 1. Writing Plugins in Pascal

Using avisynth_c.pas, you can write a standard Windows Dynamic Link Library (.dll) in Delphi or Free Pascal that processes video frames.

Loading: Because they use the C API, these plugins cannot be auto-loaded like C++ .dll files. They must be manually called inside an AviSynth script using the LoadCPlugin() or Load_Stdcall_Plugin() functions.

Functionality: A Pascal plugin can pull raw frame data (like YV12, YUY2, or RGB32), manipulate the byte array of pixels (for instance, to create a custom blur, denoiser, or watermark), and pass it back to the video pipeline. 2. Embedding AviSynth in Pascal Applications

Instead of writing filters for AviSynth, you can use Pascal to write software that reads AviSynth scripts.