DebaterXDebaterX

When to Fall Back to Stock B-Roll

Purists generate everything. Pros generate the parts that matter and buy the rest.

·4 min read

There's a dogma among AI video practitioners that says: generate everything. Every shot, every frame, every particle of the final video should come from the model. Purity.

This is wrong, and it's slow. Professional workflows mix AI-generated content with stock footage, taking advantage of each where it's strongest. Here's the decision tree.

Generate what carries the IP

The parts of your video that must be yours — your mascot, your product, your branded scene — are generation territory. That's the stuff that can't be bought off the shelf. That's where AI video's flexibility matters.

Generate:

These are the parts where the creative work lives. Spend generation time here.

Stock everything else

Generic establishing shots. City skylines. Anonymous crowds. Nature footage. Generic office environments. Laboratory close-ups of unrelated hands doing unrelated things.

All of these are available from stock libraries (Getty, Shutterstock, Pond5, Artgrid) at reasonable per-clip prices. Some are available free from Pexels or Pixabay.

For a 30-second ad with five establishing shots, stock can save you 2-3 hours of generation time at the cost of maybe $50 in licenses.

The cost math

Generation time is real money:

For generic content, all of this is wasted. A stock clip of a city skyline costs $15 and is immediately usable. A generated city skyline costs computing resources, takes 2 minutes, and looks slightly worse than stock.

Stock wins for generic content. Generation wins for specific content. Mix both.

The workflow

My production workflow:

  1. Storyboard the video, tagging each shot as "generated" or "stock."
  2. Generated shots go into the AI pipeline.
  3. Stock shots get sourced in parallel.
  4. Editor composites everything together, matching color grading for coherence.

The parallelization matters. While the AI pipeline is running (which takes minutes per shot), stock sourcing happens concurrently. Total time-to-delivery is shorter than generating everything.

The quality argument

There's an implicit claim that stock footage looks lower-quality than AI generation. This used to be true. It isn't anymore.

High-end stock libraries have 4K+ footage shot by professionals. The quality floor is high. Blended correctly with AI generation (matching color grade, frame rate, and compression), stock shots are invisible in the final cut.

Low-end stock — free Pexels clips — can be obviously stock, but that's avoidable. Budget for paid stock.

The licensing

Stock licensing is usually royalty-free for commercial use, but read the terms. Some licenses restrict:

For DebaterX, I use stock only for incidental B-roll and only from licenses that clearly permit commercial short-form video. Legal clarity is worth the small licensing fee.

The purist objection

Some creators object to mixing stock on principle. They want their work to be "fully AI-generated." This is a creative choice for some — especially artists exploring what AI video specifically can do.

For production work — ads, brand content, commercial deliverables — the purist position is self-defeating. You're not making a statement about AI's capabilities. You're making content for a client. The client doesn't care how the individual shots were made. They care about the final product's quality and cost.

Use the tool that's best for each shot. That's often AI. Sometimes it's stock. Neither is morally superior.

The rule

Your AI generation budget — time, compute, attention — is finite. Spend it on shots that can't be bought. Save it on shots that can be.

The ratio that works for me is roughly 30% generated, 70% stock-or-reused. Your ratio may differ. The principle stays the same: optimize for what AI is uniquely good at, and buy everything else.

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