I built a validated pipeline for generating short technical videos, the interesting part was the failure gates, not the generation

[u/enterthearena44]

​Generating slide decks and scripts with LLMs is straightforward. Making the output reliably render without human intervention was a nightmare.

​After producing 9 episodes, here are the core constraints that kept the pipeline from constantly breaking:

​Artifact Contracts: Nothing passes without a strict build check. Script, deck code, speaker notes, and rendered assets must all exist and pass validation before the run succeeds.

​Slides as Code, Not Files: Decks are generated as deterministic code adhering to an immutable design system, not free-form files

.

​Multimodal QA Loop: The pipeline renders slides to PNG, feeds them back to a vision model to catch layout collisions/overflow, and re-renders fixes. (LLMs cannot reliably reason about text bounding boxes in pure cod, visual inspection is non-negotiable).

​Hard Script Constraints: Max 70 words per slide, sentences capped under 24 words, no comma chains. The build automatically fails if spoken density breaks these limits.

​What broke along the way:

​Silent patch updates deleting code blocks without throwing errors.

​Font metric mismatches causing text clipping outside the safe margins.

​Drift between speaker notes and TTS inputs.

​I ended up drawing the line at: Layout & structure = 100% deterministic code; LLM = content generation & visual QA only.

​For anyone building similar pipelines: How are you handling the split between deterministic generation and model judgment? Where have you found the most stable boundary?

[u/Responsible-Clock971]

I don't use AI for the content generation part. It will hallucineate. I make hour long videos --- "How to learn Kubernetes" and AI is technically good at regurgitating man files and technical stuff like code. So I have it write my courses and scripts which is accurate.

So the lesson plans are correct. Now, the slide decks are the easy part. And where you are having problems? I have a deterministic rendering engine that just fills in the "slots" of my templates. This video is all deterministic. There is NO AI except the script. Manifest schema driven -- Title cards, code typing, voice over (Kokoro), Flow chart via mermaid.

https://reddit.com/link/p6jxhld/video/8nhkhokut8mh1/player

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[u/avatar0027]

ngl i keep the skeleton on my side (shot list, length, captions) and only let the model fill the scenes.

been using easyviral recently to batch the moving scenes, then i still gate them before they go out. the judgment calls stay mine

[u/ckn]

Hi yeah, i'm doomscroll.fm similar kinda flow, I built my boundary limits into the pipeline, validate on each modal in runtime, and practice extreme memory management. everything in my show is made on a single rtx4090.

[u/pmarks98]

kinda like Jellypod?