Generating Cinematic Video with LTX-2.3

LTX-2.3 represents a significant evolution in AI video generation. While LTX-2 introduced synchronized audio-video generation, LTX-2.3 brings architectural enhancements specifically designed for cinematic output: a 4x larger text connector for better prompt comprehension, native portrait video support, and improved multi-subject scene handling.

This guide focuses on cinematic techniques specific to LTX-2.3. For setup instructions, see our LTX-2 ComfyUI guide.

What’s New in LTX-2.3

Architectural Upgrades

Component	LTX-2	LTX-2.3
Total Parameters	19B	22B (dev)
Text Connector	Standard	4x larger gated attention
Training Data	Landscape-focused	Native portrait included
Max Duration	10s	20s
Audio Quality	Standard	Filtered training + new vocoder

The enlarged text connector is the key cinematic upgrade. It processes prompt information through deep attention layers with a gated mechanism that improves:

• Complex spatial relationships between multiple subjects
• Temporal event sequencing (“at the 3-second mark”)
• Character positioning relative to camera and scene elements

Generation Flows

LTX-2.3 introduces two distinct generation flows:

Fast Flow — Optimized for speed:

• Distilled model with 3-4x faster generation
• Best for iterative testing and rapid prototyping
• 10s at 1344x768: ~57 seconds on RTX 4090

Pro Flow — Optimized for quality:

• Full 22B parameter model
• Better prompt adherence and detail
• 5s at 1344x768: ~115 seconds on RTX 4090

Native Portrait Video

LTX-2.3 is the first model trained natively on 9:16 portrait video. Previous models cropped landscape content, losing quality at edges. LTX-2.3 generates:

• 1080x1920 native resolution
• Properly composed vertical framing
• Vertical-appropriate camera movements (tilt vs pan)

LTX-2.3’s native portrait support enables proper 9:16 composition

Enhanced Multi-Subject Scenes

The larger text connector enables accurate multi-subject composition. Key improvements:

1. Spatial anchoring — “A man on the left, woman on the right” maintains positions
2. Action handoffs — Characters can interact: “He hands her the cup”
3. Dialogue timing — Better understanding of “then she replies”

New Upscaling Models

LTX-2.3 includes dedicated upscalers:

• Spatial Upscaler — Increase resolution post-generation
• Temporal Upscaler — Add frames for smoother motion

These enable a two-stage production pipeline: generate low-res, upscale to 4K.

The 9 Cinematic Prompting Rules (LTX-2.3 Deep Dive)

LTX-2.3’s larger text connector allows for longer, more detailed prompts without degrading output quality. Use this to your advantage.

1. Single Continuous Paragraph

Write prompts as one flowing narrative. LTX-2.3’s gated attention processes the entire prompt holistically.

A lone fisherman rows across a foggy lake before sunrise, the boat creaking 
softly as water laps at its sides. The camera glides overhead in a slow 
tracking shot, following his progress through the mist. His lantern casts 
a warm circle of light on the water while distant reeds sway on the shore.

2. Present-Tense Action Verbs

Always use present tense: “walks”, “tilts”, “flickers” — not “walked” or “is walking”.

A young boy runs barefoot across a wet stone courtyard as raindrops begin 
to fall. The camera tracks behind him at low angle, catching splashes beneath 
his feet. He turns sharply, arms outstretched for balance.

3. Explicit Camera Behavior

LTX-2.3’s text connector excels at camera instructions. Define perspective, angle, movement, and speed precisely.

The camera begins in a wide shot from across the street, then slowly pushes 
forward at shoulder height as pedestrians blur in the foreground. A passing 
bicycle crosses the frame before the shot settles into a medium close-up.

4. Precise Physical Details

Small, measurable movements create believable motion.

Her eyebrows lift slightly as she hears a creak behind her, and the knife 
pauses mid-air. The camera holds in medium close-up with shallow depth of 
field, capturing the tension in her wrist and the gleam of metal.

5. Atmospheric Environment

Include lighting, air quality, textures, and ambient elements.

Pale blue light from an overcast sky diffuses across the scene, softening 
the edges of distant waves. A cool breeze ripples through her hair while 
seagulls call overhead and fog begins to roll in from the horizon.

6. Smooth Temporal Flow

Use connectors: “as”, “then”, “while”, “when”.

As the camera begins in a stationary wide shot, a figure steps forward 
through the haze. Then the camera glides sideways, following its stride 
while it moves toward a glowing console on the far side of the room.

7. Genre-Specific Language

Match vocabulary to your intended aesthetic.

A maintenance drone glides through a long tunnel inside a deep space cargo 
vessel, its circular frame rotating slowly as it shines beams of light on 
the walls. Soft mechanical hums blend with the distant low thrum of the 
ship's reactor core.

8. Character Specificity

Only include observable details:

A middle-aged South Asian man in a long tan coat steps into a narrow alley 
lit by neon signage. Rain hits the cobblestones as the camera tilts up from 
his shoes, revealing his profile in close-up against the glowing signs.

9. Show, Don’t Tell Emotion

Never describe feelings. Describe body language.

Don’t Write	Do Write
”He is nervous"	"His fingers tighten on the railing, breathing slows as he steadies himself"
"She is sad"	"A single tear trails down her cheek. Her shoulders drop"
"He is confident"	"Back straight, gestures controlled and deliberate”

Multi-Subject Scene Strategies

LTX-2.3’s enhanced text connector enables complex multi-character scenes previously impossible.

The Handoff Technique

For scenes with multiple characters, describe actions sequentially:

A woman in a red dress stands by the window. A man enters from the left, 
crosses to her, and hands her a cup. She takes it, then turns to face 
the camera as he exits frame right.

Spatial Anchoring

Position subjects explicitly:

On the left side of the frame, a young girl draws on a notepad. On the 
right, her mother watches from a doorway. The camera slowly pulls back 
to reveal both in a medium two-shot.

Dialogue Timing

LTX-2.3 understands temporal markers:

The reporter looks into the camera and speaks with an energetic voice: 
"Thank you, Sylvia." A beat passes. Then: "This morning, here in New Castle, 
Vermont—black gold has been found!" Ambient construction sounds fill 
the background throughout.

Long-Shot Strategy (15-20 Seconds)

LTX-2.3’s 20-second maximum enables true long-take shots. Structure these as mini-scenes:

Scene Architecture

**Scene Heading:** Location and time
**Brief Description:** Overall atmosphere
**Blocking:** Sequence of actions + camera movements
**Dialogue/Cues:** Performance notes

Example (18-second shot)

Scene: A pilot's cockpit at sunset, orange light flooding through the canopy.

Blocking: Start macro on gloved hand gripping the flight stick. Slowly pull 
back to medium shot revealing helmet reflection on the instrument panel. 
Camera continues pulling back through the cockpit glass into a wide exterior 
shot showing the aircraft banking over clouds.

Cues: Metallic creaks, radio static, wind noise increasing as we move outside.

Cinematic lighting and atmosphere—the noir aesthetic demonstrates LTX-2.3’s ability to handle high-contrast scenes

Two-Stage Upscaling Pipeline

For production quality at 4K:

Stage 1: Generate Low-Res

Generate at 1344x768 or 1024x576 for speed:

Resolution: 1344x768
Frames: 121 (5s at 24fps)
Flow: Fast (for testing) or Pro (for final)

Stage 2: Spatial Upscale

Apply LTX-2.3’s spatial upscaler:

Input: Stage 1 output
Target: 2688x1536 or higher
Method: LTXVSpatialUpscaler

Stage 3: Temporal Upscale (Optional)

Add intermediate frames for smoother motion:

Input: Upscaled video
Target frames: 241 (10s at 24fps)
Method: LTXVTemporalUpscaler

Performance Benchmarks

Resolution	Frames	Time (RTX 4090)
1344x768	121	~57s (Fast), ~115s (Pro)
1536x896	121	~85s (Fast), ~180s (Pro)
With upscale	121	+45s spatial, +30s temporal

Enhanced I2V (Image-to-Video)

LTX-2.3’s Image-to-Video sees significant improvements:

Better Motion Interpretation

The model now understands complex motion requests:

Input: Photo of a chef in a kitchen
Prompt: The chef begins chopping vegetables with practiced precision. 
Steam rises from the pot behind him. Camera slowly pushes in to 
medium close-up on his hands and knife.

Progressive Prompt Building

Start simple, add complexity:

1. Base: “The subject turns to face the camera”
2. Add atmosphere: “in a dimly lit room with venetian blind shadows”
3. Add motion: “Camera slowly pushes in, catching dust motes in the light”

First Frame Consideration

Your I2V prompt describes what happens after the first frame. The input image defines position, lighting, and composition. Your prompt only defines:

• Camera movement
• Subject motion
• Environmental changes
• Timing (“after 2 seconds…”)

What Works vs What to Avoid

Works Well

Technique	Why
Shallow depth of field	Model trained on cinematic footage
Explicit camera language	4x text connector parses camera terms accurately
Atmospheric elements	Fog, rain, reflections render beautifully
Stylized aesthetics	Noir, film grain, fashion editorial
Portrait composition	Native 9:16 training

Known Issues

Issue	Mitigation
Random background music	Currently no fix—audio can include unexpected tracks
Ken Burns effect instead of motion	Request explicit camera movement in prompt
Slowdown in second half	Keep clips shorter or use temporal upscale

Production Workflow

Recommended Pipeline

1. Fast Flow (testing) → Iterate on prompts quickly
2. Pro Flow (final) → Generate at target resolution
3. Spatial Upscale → Increase resolution
4. Temporal Upscale (optional) → Add frames
5. Assembly → Combine clips in editor

Multi-Clip Production

For a 60-second video requiring 6 clips:

Clip 1 (8s): Fast flow, 1344x768, test prompt
Clip 2 (8s): Adjust based on Clip 1 results
Clip 3 (8s): Iterate
...continue...
Final: Pro Flow at 1536x896, spatial upscale to 3072x1728
Total time: ~6 minutes for 6 clips at Pro quality

Summary

LTX-2.3’s architectural improvements make it a genuine tool for cinematic video production:

• 4x larger text connector enables longer, more detailed prompts
• Native portrait support opens mobile-first content creation
• Multi-subject handling allows complex scene composition
• Extended duration (20s) enables long-take cinematography
• Upscaling models provide production-quality output

The key is treating the model as a cinematography tool, not a magic box. Write prompts like a director’s shot list: establish, compose, move, and cut. LTX-2.3 will follow.

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Resources

• Official Documentation: Lightricks/LTX-Video on GitHub
• Model Downloads: Hugging Face
• Prompting Guide: docs.ltx.video
• Community: r/StableDiffusion