From source to published video

Three commands expose the main stages of ClipAsm:

This separation lets you catch source problems quickly and lets unused media stay unopened.

1. Read and check the source

ClipAsm parses the root .clipasm file and its imports, then checks every linked source program. It resolves calls, arguments, types, stack inputs, names, and ordered outputs.

This stage does not open authored media. Durations written directly in source can already be exact. Durations that depend on a media file remain unknown until rendering.

An unused imported program must still be valid source because the compiler checks the complete linked package.

2. Prepare reachable media and tools

During render, preflight starts from the one Video selected for publication and follows only the work needed to produce it. It resolves paths, hashes source assets, probes media, checks required FFmpeg capabilities, and locates reachable external executables.

This means an unused import can contain an unused missing media file without blocking rendering, as long as the imported source itself is valid.

3. Execute, verify, and publish

ClipAsm reuses verified cached artifacts when possible and executes the missing work in dependency order. With fused materialization, compatible FFmpeg operations that lead to one materialized endpoint share one filter graph. Branches may join that region when they divide a Video’s picture and Audio without duplicating either physical stream. Cache hits, duplicated streams, temporal joins, external programs, input-scoped FFmpeg behavior, and branches that require different materialized endpoints remain artifact boundaries. Keeping temporal-join inputs separate prevents fused preprocessing on a later branch from being buffered for the length of an earlier one. Cache retention and intermediate materialization are separate settings. External programs reached here run as trusted native code.

The renderer checks produced media before it enters the cache or replaces the published output. A successful render writes the MP4 and a sibling manifest.

Rendering requires exactly one Video output. Additional Audio outputs may exist, but ClipAsm does not publish them separately.

Terms used in reference pages

• compiled program: the checked media-independent result used by inspect
• preflight: the media and tool resolution that render performs
• prepared plan: the exact reachable work after preflight
• publication: verification and final replacement of the MP4 and manifest

See the command-line reference for exact command behavior.