LTX 2.3: Fast Flow vs Pro Flow, 4K, and Prompt Tips

Lightricks officially released LTX 2.3 on March 8, 2026 - and it is one of the most significant open-source AI video upgrades of the year. The model introduces a rebuilt video engine with native 4K output, native portrait video, a 4x larger text connector, and synchronized audio generation, all under the Apache 2.0 license, meaning it is free to use commercially.

This guide covers what actually changed, how Fast Flow compares to Pro Flow, practical prompt tips, and how to get started with LTX 2.3 on Veevid.

What Is LTX 2.3?

LTX 2.3 is the latest video generation release from Lightricks. The official release positions it as a major upgrade over the earlier LTX generation with:

• sharper fine detail from a rebuilt latent space and VAE
• stronger prompt understanding from a larger text connector
• better image-to-video motion with less "Ken Burns" drift and fewer static clips
• native portrait support instead of landscape-first adaptation
• cleaner audio output and audio-conditioned generation in the broader LTX 2.3 ecosystem

For creators, the practical takeaway is simple: LTX 2.3 is designed to make AI video more useful for real production work, not just short experiments.

What Changed in LTX 2.3

1. Better Fine Detail

Lightricks says LTX 2.3 was rebuilt with a new latent space and VAE. That matters because earlier video models often blurred small details, especially on hair, fabric, textured surfaces, and close-up product shots.

This is easiest to see in shots with dense texture and layered lighting.

2. Better Prompt Adherence

One of the official release highlights is a 4x larger text connector. In practice, that means LTX 2.3 is better at:

• following multi-subject prompts
• preserving left/right and foreground/background relationships
• holding onto more attributes from longer prompts
• keeping cinematic instructions more coherent across the clip

This is especially relevant for prompt-heavy workflows like product ads, storyboard generation, and multi-element social videos.

3. Better Image-to-Video Motion

The release notes call out two failure modes directly: the Ken Burns effect and static image-to-video outputs. LTX 2.3 is designed to reduce both, which makes it more useful for actual I2V animation instead of fake camera movement over a still image.

4. Native Portrait Video (9:16)

LTX 2.3 supports native portrait output - 9:16 is composed natively from the start instead of feeling like a landscape render that gets cropped later. For TikTok, Reels, Shorts, and mobile-first ads, that means framing, motion, and scene balance are built for vertical viewing on the first pass.

5. Native Audio Generation

Most AI video models generate silent clips. LTX 2.3 generates video and synchronized audio in a single pass - ambient sound, dialogue, and sound effects are produced alongside the video rather than layered in afterward.

The practical difference is significant: the timing between what you see and what you hear is determined by the model itself, not by post-production alignment. LTX 2.3 also ships with a newly updated vocoder that increases dialogue clarity and reduces the artifacts that made earlier audio outputs sound hollow or misaligned.

For creators building social ads, product demos, or any content where audio matters, this changes the workflow meaningfully - you are not starting with a silent clip and hunting for stock sound. The model gives you a working audio-video draft to iterate from.

LTX 2.3 Fast Flow vs Pro Flow

	LTX 2.3 Fast Flow	LTX 2.3 Pro Flow
Best fit	Ideation, iteration, storyboard passes	Final output, higher-fidelity renders
Speed	Faster turnaround	Slower, more quality-focused
Official positioning	Rapid generation	Highest-quality generation
Duration flexibility	Up to 20s	Up to 10s
Resolution	Up to 2160p	Up to 2160p
Key tradeoff	Better for longer iterations	Better for shorter final renders

The practical workflow is straightforward:

1. Start with Fast Flow when you are exploring concepts or testing multiple prompt directions.
2. Switch to Pro Flow when you have a prompt that already works and you want the cleaner final render.

If your use case is social creative iteration, Fast Flow will usually be the better first stop. If your use case is client-facing delivery or polished ad output, Pro Flow is the mode to finish with.

For reference, the official release positions LTX 2.3 around native 4K output, native portrait support, improved image-to-video motion, a 4x larger text connector, and cleaner audio workflows. On Veevid today, the current implementation focuses on text-to-video and image-to-video with Fast Flow / Pro Flow options, and the current API supports portrait output up to 2160×3840.

Best LTX 2.3 Prompt Tips

LTX 2.3 benefits from prompts that are concrete, directional, and visual. The model performs best when you describe:

• the subject
• the environment
• the camera behavior
• the lighting
• the motion
• the intended visual tone

Good prompting pattern:

subject + environment + action + camera move + lighting + texture + mood

Prompt Template: Product Ad

"A premium glass perfume bottle on a wet black stone surface, tiny water droplets and soft mist in the air, camera slowly pushes in, dramatic rim light, high contrast reflections, luxury commercial style, ultra-detailed textures"

Prompt Template: Portrait Social Video

"A stylish woman in a red leather jacket walking through a neon-lit city street at night, vertical 9:16 composition, subtle handheld camera movement, glowing signs in the background, cinematic depth of field, realistic motion, cool blue and magenta lighting"

Prompt Template: Image-to-Video Motion

"Animate the subject naturally with a gentle head turn and fabric movement, preserve facial identity, avoid aggressive zoom, realistic body motion, soft cinematic lighting, stable framing"

Who Should Use LTX 2.3?

LTX 2.3 is a strong fit for:

• short-form creators who need native portrait outputs
• marketing teams that want to iterate quickly in Fast Flow and finish in Pro Flow
• product teams creating polished demo videos and ad concepts
• agencies comparing hosted AI video options before scaling usage
• developers evaluating an open LTX workflow against closed model alternatives

If your workflow depends on fast idea volume plus credible production quality, LTX 2.3 is one of the most relevant models to test right now.

How to Use LTX 2.3 on Veevid

If you want the quickest path from search to output, this is the simplest flow:

Step 1: Open the tool

Go to LTX 2.3 on Veevid, or jump directly to Text to Video or Image to Video.

Step 2: Pick Fast Flow or Pro Flow

Use Fast Flow for exploration. Use Pro Flow when your prompt is already working and you want the better final result.

Step 3: Choose duration, resolution, and aspect ratio

If you need a longer clip, Fast Flow is the more flexible option. If you are creating social content, 9:16 is the obvious starting point.

Step 4: Write a direct visual prompt

Keep the prompt specific. Mention the camera, the motion, and the scene detail you care about most.

Step 5: Generate, review, and iterate

The best LTX 2.3 workflow is usually iterative: test in Fast Flow, then move the winner into Pro Flow.

Frequently Asked Questions

What is LTX 2.3 best at?

LTX 2.3 stands out for native portrait support, sharp high-resolution detail, stronger prompt adherence, and a Fast Flow vs Pro Flow workflow that fits both exploration and more polished output.

Is LTX 2.3 really 4K?

Yes. The official model positioning highlights output up to 4K. On Veevid, the generator currently exposes 1080p, 1440p, and 2160p.

What is the difference between LTX 2.3 Fast Flow and Pro Flow?

Fast Flow is optimized for speed and iteration. Pro Flow is the quality-oriented option for final renders. On Veevid today, Fast Flow also supports the longer duration range.

Is LTX 2.3 good for TikTok, Reels, and Shorts?

Yes. Native portrait support is one of the clearest reasons to use LTX 2.3 for vertical social video.

Can I use LTX 2.3 commercially?

Yes. All videos you create with LTX 2.3 through Veevid are yours to use for personal and commercial purposes, including social media content, advertising, client projects, and more, without additional licensing fees.

The Bottom Line

LTX 2.3 is not just interesting because it is new. It is interesting because it lines up with the exact features that creators and buyers are already searching for: 4K AI video, better prompt adherence, native vertical output, and faster iteration.

If you want a practical way to test it right now, start with LTX 2.3 on Veevid, use Fast Flow to explore, and switch to Pro Flow for the final pass.