/ltx2

name: ltx2
description: AI video generation with LTX-2.3 22B — text-to-video, image-to-video clips for video production. Use when generating video clips, animating images, creating b-roll, animated backgrounds, or motion content. Triggers include video generation, animate image, b-roll, motion, video clip, text-to-video, image-to-video.

LTX-2.3 Video Generation

Generate ~5 second video clips from text prompts or images using the LTX-2.3 22B DiT model. Runs on Modal (A100-80GB). Requires `MODAL_LTX2_ENDPOINT_URL` in `.env`.

Quick Reference

# Text-to-video
python3 tools/ltx2.py --prompt "A sunset over the ocean, golden light on waves, cinematic" --output sunset.mp4

# Image-to-video (animate a still image)
python3 tools/ltx2.py --prompt "Gentle camera drift, soft ambient motion" --input photo.jpg --output animated.mp4

# Custom resolution and duration
python3 tools/ltx2.py --prompt "..." --width 1024 --height 576 --num-frames 161 --output wide.mp4

# Fast mode (fewer steps, quicker)
python3 tools/ltx2.py --prompt "..." --quality fast --output quick.mp4

# Reproducible output
python3 tools/ltx2.py --prompt "..." --seed 42 --output reproducible.mp4

Parameters

| Parameter | Default | Description | |-----------|---------|-------------| | `--prompt` | (required) | Text description of the video | | `--input` | - | Input image for image-to-video | | `--width` | 768 | Video width (divisible by 64) | | `--height` | 512 | Video height (divisible by 64) | | `--num-frames` | 121 | Frame count, must satisfy `(n-1) % 8 == 0` | | `--fps` | 24 | Frames per second | | `--quality` | standard | `standard` (30 steps) or `fast` (15 steps) | | `--steps` | 30 | Override inference steps directly | | `--seed` | random | Seed for reproducibility | | `--output` | auto | Output file path | | `--negative-prompt` | sensible default | What to avoid |

Valid Frame Counts

`(n - 1) % 8 == 0`: 25 (~1s), 49 (~2s), 73 (~3s), 97 (~4s), **121 (~5s default)**, 161 (~6.7s), 193 (~8s max practical).

Common Resolutions

| Resolution | Ratio | Notes | |------------|-------|-------| | 768x512 | 3:2 | Default, good balance | | 512x512 | 1:1 | Square, fastest | | 1024x576 | 16:9 | Widescreen | | 576x1024 | 9:16 | Portrait/vertical |

Prompting Guide

LTX-2 responds well to cinematographic descriptions. Layer these dimensions:

• **Camera:** "Slow dolly forward", "Aerial drone shot", "Tracking shot", "Static wide angle"
• **Lighting:** "Golden hour", "Cinematic lighting", "Neon-lit", "Soft diffused light"
• **Motion:** "Timelapse of...", "Slow motion", "Gentle camera drift", "Gradually transitions"
• **Style:** "Shot on 35mm film", "Documentary style", "Clean minimal aesthetic"
• **Negative:** Always implicitly avoids "worst quality, blurry, jittery, watermark, text, logo"

Keep prompts under 200 words. Be specific about the scene.

Good Prompts

# Atmospheric b-roll
"Aerial drone shot slowly flying over turquoise ocean waves breaking on white sand, golden hour sunlight, cinematic"

# Product/tech scene
"Close-up of hands typing on a mechanical keyboard, shallow depth of field, soft desk lamp lighting, cozy atmosphere"

# Abstract background
"Dark moody abstract background with flowing blue light streaks, subtle geometric grid, bokeh particles floating, cinematic tech atmosphere"

# Animate a portrait
"Professional headshot, subtle natural head movement, confident warm expression, studio lighting, shallow depth of field"

# Animate a slide/screenshot
"Gentle subtle particle effects floating across a presentation slide, soft ambient light shifts, very slight camera drift"

Bad Prompts

# Too vague
"A cool video"

# Too many competing ideas
"A cat riding a skateboard while juggling fire on the moon during a thunderstorm"

# Describing text/UI (model can't render text reliably)
"A website showing the text 'Welcome to our platform'"

Video Production Use Cases

B-Roll Clips

Generate atmospheric 5s shots for cutaways between narrated scenes:

python3 tools/ltx2.py --prompt "Futuristic holographic interface, glowing data visualizations, clean workspace, cinematic" --output broll_tech.mp4
python3 tools/ltx2.py --prompt "Aerial view of European city at golden hour, modern architecture" --output broll_europe.mp4

Animated Slide Backgrounds

Feed a slide screenshot and add subtle motion:

python3 tools/ltx2.py --prompt "Gentle particle effects, soft ambient light shifts, very slight camera drift" --input slide.png --output animated_slide.mp4

Animated Portraits

Bring still headshots to life:

python3 tools/ltx2.py --prompt "Subtle natural head movement, warm expression, professional lighting" --input headshot.png --output animated_portrait.mp4

Branded Intro/Outro

Generate abstract motion backgrounds for title cards:

python3 tools/ltx2.py --prompt "Dark moody background with flowing blue and coral light streaks, bokeh particles, cinematic tech atmosphere, no text" --output intro_bg.mp4

Combining with Other Tools

LTX-2 generates raw clips. Combine with the rest of the toolkit:

| Workflow | Tools | |----------|-------| | Generate clip → upscale | `ltx2.py` → `upscale.py` | | Generate clip → add to Remotion | `ltx2.py` → use as `<OffthreadVideo>` in composition | | Generate image → animate | `flux2.py` → `ltx2.py --input` | | Generate clip → extract audio | `ltx2.py` → `ffmpeg -i clip.mp4 -vn audio.wav` | | Generate clip → add voiceover | `ltx2.py` → mix with `qwen3_tts.py` output |

Technical Details

• **Model:** LTX-2.3 22B DiT (Lightricks), bf16
• **GPU:** A100-80GB on Modal (~$4.68/hr)
• **Inference:** ~2.5 min per clip (768x512, 121 frames, 30 steps)
• **Cost:** ~$0.20-0.25 per 5s clip
• **Cold start:** ~60-90s (loading ~55GB weights)
• **Output:** H.264 MP4 with synchronized ambient audio (24fps)
• **Max duration:** ~8s (193 frames) per clip

Known Limitations

• **Training data artifacts:** ~30% of