SOpen

LTX-2.3

Lightricks

The open-source flagship. First open model to close the gap with proprietary leaders.

SClosed

Runway Gen-4.5

Runway

The creative director's tool. Industry benchmark for character consistency.

Pick LTX-2.3 if…

You want open-source audio-video, or studios needing IP control.

Pick Runway Gen-4.5 if…

You want brand campaigns, character-consistent series, or agency production.

Specifications

Maker
Lightricks
Runway
Source Type
Open Source
Closed Source
License
Apache 2.0 (<$10M rev)
Commercial (subscription)
Architecture
DiT (22B) + Rebuilt VAE
Proprietary DiT
Parameters
22B
Undisclosed
Max Resolution
4K
1080p (upscaled 4K)
Max Duration
20s
10s clips
FPS
Up to 50
24-30
Native Audio
Yes
Yes
ComfyUI Support
Yes
No
Fine-tunable
Yes
No
Min VRAM
32GB (full) / 12GB (distilled)
Cloud only
Cost / Second
$0.04
~$0.15 (credits)
Inputs
T2V, I2V, V2V, Audio-cond
T2V, I2V, References
On Floyo
Yes
No

Strengths & Trade-offs

LTX-2.3

Strengths

  • +22B params
  • +true 4K at 50fps
  • +first open model with synced audio
  • +rebuilt VAE
  • +native portrait

Trade-offs

  • -Full 4K needs 48GB
  • -dialogue lip-sync inconsistent
  • -in-scene text flaky

Best For

  • Local 4K production
  • open-source audio-video
  • studios needing IP control

Runway Gen-4.5

Strengths

  • +Best character consistency (References)
  • +Motion Brush
  • +30-90s gen
  • +30+ tools
  • +Act-Two mocap

Trade-offs

  • -10s clip limit
  • -opaque credits
  • -T2V inconsistent without guidance

Best For

  • Brand campaigns
  • character-consistent series
  • agency production