LTX-2.3 Fast Text to Video: Prompts to Clips Up to 4K
Last verified: October 19, 2026
LTX-2.3 Fast renders portrait and landscape video at up to 4K and cinematic frame rates, and speed stays its priority. Working in LTX-2.3 Fast text-to-video comes down to three choices: the shot you describe in the Prompt box, the Resolution (4K on a short clip that has to hold up on a big screen) and a vertical or widescreen frame under Aspect Ratio.
You describe the scene, the camera motion and the mood, and the model returns a video with matching audio. Leave the Generate Audio switch on and write the sound into the prompt with the same care as the picture: rain on a window, a line of dialogue, a crowd in the distance. Switch it off when you only need the picture.
LTX-2.3 follows descriptions of timing, motion and expression closely. That makes the Fast tier a practical place to work out ideas, and Lightricks positions it for rapid iteration, storyboards and previews. Use it to test a concept, check framing and pacing, and build up a set of rough shots before you commit to a final cut.
Explore more text to video
LTX-2.3 Fast at a Glance
What you put in, what you can set and what comes back from each text-to-video run.
Input
A text prompt of up to 2,048 characters
Video Duration
6, 8, 10, 16 or 20 seconds
Resolution
1080P, 2K or 4K, depending on the duration
Aspect Ratio
9:16, 16:9
Audio
Switch on or off, on by default
Output
1 video per run
How Do You Prompt LTX-2.3 Fast for Better Clips?
Write One Flowing Shot Description
Spell Out Who Stands Where
Name the Camera Move in Film Terms
Making a Clip with LTX-2.3 Fast
Four steps from a written idea to a downloaded clip.
LTX-2.3 Fast or LTX-2.3 Pro: Which Should You Use?
How Lightricks' Fast and Pro tiers of LTX-2.3 divide the work, according to the creator's own specs.
| Criterion | LTX-2.3 Fast | Alternatives | Best For |
|---|---|---|---|
| What it is tuned for | It is built for high-speed generation and aimed at rapid iteration, storyboards and previews. | LTX-2.3 Pro is the higher-fidelity tier, documented for higher detail and motion stability in final, commercial-grade renders. | Work in LTX-2.3 Fast while you are still finding the shot, then render the version that ships with LTX-2.3 Pro when detail and steady motion matter most. |
| Longest single clip | Its longest clips come at 1080p, twice the length Pro allows, while its 1440p and 4K output stops at ten seconds. | LTX-2.3 Pro tops out at ten seconds at every resolution it offers. | Pick LTX-2.3 Fast for any shot that has to run longer than ten seconds in one generation; at ten seconds or under, length is no reason to choose one over the other. |
| Resolution and frame-rate ceiling | It is documented at up to 4K and up to 50 fps, in both portrait and landscape. | LTX-2.3 Pro is documented with the same 4K and 50 fps ceiling in both orientations. | Both tiers reach the same ceiling, so choose between them on clip length and finish quality, not on resolution. |
Fixing Common LTX-2.3 Fast Problems
What usually goes wrong with a clip made from text alone, and what to change before the next run.
The action feels rushed in a longer clip
The video ignores part of my prompt
I can't pick 2K or 4K for a long clip
The background sound is thin when nobody speaks
Frequently Asked Questions
Does LTX-2.3 Fast generate audio with the video?
Yes. LTX-2.3 generates synchronized video and audio within a single model, and the Generate Audio switch decides whether your clip includes sound. Turn it off when you only need the picture, for example when the clip will be cut to your own music track.
Will Enhance Prompt overwrite what I typed?
No. Enhance Prompt suggests fuller prompts based on your rough idea, and the text in the Prompt box only changes when you pick one of the suggestions. Use it to turn a one-line concept into a first draft, then add what only you know, such as exact dialogue or the specific camera move.
What makes one generation cost more than another?
The credit cost of a run is worked out from the options you choose and shown above the Generate button once you're signed in. Video Duration and Resolution are the settings that change it, so you'll see the figure move as you adjust the clip length or resolution before you generate. Enhance Prompt suggestions don't use credits.
How do I write dialogue for a speaking character?
Break long lines into short phrases with acting directions between them. Direct the performance with physical cues, like a glance down, a pause or a hand tightening on a cup, rather than emotional labels. Describe the character's voice and the acoustic environment too, and keep Generate Audio on so the lines are spoken in the soundtrack.