Only the end of your film is cheap to change

Most advice about product video is about what to put in it. This is about something duller and, once you have paid for a few, more useful: which parts of a finished film you can still change, and what each change costs.

Two edits that cost nothing

A finished film can be trimmed, and it can be re-cut to another shape around a point you choose. Both are free, and neither disturbs the film you already have — each writes a new file of its own, so the original is always still there and an edit can be redone from scratch as many times as you like. A trim has one rule: keep at least a second.

These are worth reaching for first precisely because they are free, and because two of the most common complaints live here. "It drags at the end" is a trim. "Once it is square, the product sits too far left" is a re-crop, and you pick the point it centres on rather than accepting the middle of the frame.

Two edits that cost a beat

The other two buy new footage, so they cost what new footage costs: eight credits for ten seconds, the same rate as any other ten seconds. You can extend a film by another ten, continuing from where it ended. Or you can retake — refilm the last ten seconds, optionally with a new instruction, keeping everything before them exactly as it was.

That second one is the interesting one, and the reason for this post.

The asymmetry

A film longer than ten seconds is not rendered as one continuous thing. It is rendered in ten-second beats, each continuing from the one before, and a retake works by keeping the beats already rendered and re-queueing only the final one. That is what makes it cost eight credits instead of the whole film.

It is also what makes it one-directional. The chain can resume, but it can only resume forwards. To change the second beat of a forty-second film you would have to re-render the second, third and fourth, because each was conditioned on the one before it — at which point you are not editing, you are buying most of a new film.

• The last ten seconds: eight credits to refilm, or eight to add ten more.
• Length and framing, anywhere in the film: free.
• Anything else about an earlier beat: the price of a new film.

So put your doubt at the end

This turns running order into a cost decision as well as a creative one. If you are confident about the opening and unsure how you want it to finish — a resolve on the logo, a final turn, a held hero shot — the unsure part is in the cheapest position, and you can try it twice for eight credits.

Invert that and you pay for it. A film whose first beat is the experiment and whose later beats are settled has put the expensive change at the front. Nothing is broken; it simply means the only way to revise the opening is to shoot the film again.

This is not an argument for burying your best idea. A first frame still has to earn the play, and an opening beat that does not work is not rescued by being cheap to keep. It is an argument for knowing, before you render, which part of the film you are least sure about — and if that part is negotiable in the running order, putting it where a second attempt costs one beat instead of four.

Two limits worth knowing before you plan around this

A ten-second film has no last beat to retake, because it is all one beat. Regenerating it is the only option, and that is a fresh take of the whole thing at the usual price. The shortest film is, in this one narrow sense, the least revisable — worth remembering when you are deciding between ten seconds and twenty.

And an edit needs the backend the film was rendered on. A film made before a change of video model cannot be continued by a different one, because the handle it would resume from belongs to the model that made it. If a film matters and you might want to extend it later, extend it while it is current rather than months on.

The short version

Trim and re-crop are free and always available, so try them before you spend anything. Extending or retaking costs one beat, and reaches only the end of the film. Everything earlier is settled at render time. Plan the order so the beat you are least certain about is the last one.