Video generatorConfigure here, generate in the appUpdated
Turn a script into a finished video built from real licensed HD and 4K clips, matched to what's being said, with voiceover and captions.
Paste a script and ShortFast builds a video around it, choosing licensed stock clips that match each line rather than looping one generic background for the whole thing. Voiceover is generated from the script and captions are burned in. In the app this is the Documentary style, one of 27 styles. The box above sets up the video; generating it needs a ShortFast account, which starts with a 3-day trial for $1.
The reason to use real footage rather than generated visuals is straightforward: it looks like footage, because it is. For anything you intend to monetise or put a brand name on, that difference is worth more than the novelty of fully synthetic video.
How it works
Write it yourself or start from a topic. The script drives both the narration and the footage selection.
Clips are selected against the meaning of each segment, so the visuals track the narration instead of looping.
Pick a narration voice. Captions are generated from the audio and burned into the frame.
Download it, or connect accounts and have ShortFast post on a schedule.
Most tools that claim to turn scripts into video pick one clip per paragraph, or worse, loop a single ambient background for sixty seconds. Both read as filler, and viewers disengage because the visuals stop carrying information after the first two seconds.
Good footage selection tracks the meaning of the narration. When the script mentions a specific object, place or action, the shot should change to match it. That's what makes the difference between a video and a slideshow with a voiceover over it.
It also affects retention mechanically. A visual change resets attention, which is why edited content holds viewers better than a static shot. Roughly one shot change every two to four seconds is a reasonable target for short-form.
Pulling clips from a search engine or ripping them from other people's videos is the most common way new creators get their channels demonetised or struck. Platforms are efficient at detecting reused content, and a copyright strike on a monetised channel is a serious problem.
Using licensed stock footage removes that risk. ShortFast's clips are licensed for commercial use, with nothing to attribute, so a channel built on them can be monetised without an ownership question hanging over every upload.
This is also why exported videos shouldn't carry watermarks. A watermark from another tool marks the video as third-party content, and Instagram in particular has historically reduced the reach of Reels carrying visible external watermarks.
The two aren't interchangeable. Stock footage is real, which means it looks real and behaves correctly, hands have five fingers and text on signs says words. AI-generated visuals can produce shots that don't exist in any library, which is genuinely useful for abstract concepts.
For monetised channels the safer default is stock, with AI b-roll used where a specific shot is unavailable. Channels built entirely on synthetic visuals attract more scrutiny under platform quality policies aimed at mass-produced content.
For ads and product marketing the calculation shifts, since brand-specific imagery often doesn't exist in any stock library and a generated shot is the only way to get it.
Explainers and educational content are the natural fit, because the narration carries the information and the footage illustrates it. Finance, history, science, how-to and news commentary all work well in this format.
It also suits business and marketing video, where you need something professional-looking quickly and don't have a production budget. A 30-second explainer built from licensed clips looks considerably better than a phone recording in an office.
Where it's weaker is anything requiring a specific person, place or product. If the video is about your product, no stock library contains footage of it, and you'll want screen recordings or generated visuals instead.
FAQ
Keep going
Mix stock footage with AI b-roll for faceless channels.
OpenToolFor shots no stock library has.
OpenToolStart from a script you've already written.
OpenFeatureHow footage gets matched to narration.
OpenUse caseWhere stock footage stops being the right tool.
OpenPlatformPublishing these on a daily schedule.
OpenStyleThe style behind this tool: writing a documentary short the footage can carry.
OpenStyleReal footage for real things, an AI image for ideas.
OpenShortFast writes the script, generates the video, adds captions, and posts it to TikTok, Reels, and YouTube Shorts for you, every day.
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