Member of Technical Staff, Model Evaluation

Captions is the leading video AI company, building the future of video creation. Over 10 million creators and businesses have used Captions to create videos for social media, marketing, sales, and more. We're on a mission to serve the next billion.

We are a rapidly growing team of ambitious, experienced, and devoted engineers, researchers, designers, marketers, and operators based in NYC. You'll join an early team and have an outsized impact on the product and the company's culture.

We’re very fortunate to have some the best investors and entrepreneurs backing us, including Index Ventures (Series C lead), Kleiner Perkins (Series B lead), Sequoia Capital (Series A and Seed co-lead), Andreessen Horowitz (Series A and Seed co-lead), Uncommon Projects, Kevin Systrom, Mike Krieger, Lenny Rachitsky, Antoine Martin, Julie Zhuo, Ben Rubin, Jaren Glover, SVAngel, 20VC, Ludlow Ventures, Chapter One, and more.

Check out our latest financing milestone and some other coverage:

The Information: 50 Most Promising Startups

Fast Company: Next Big Things in Tech

The New York Times: When A.I. Bridged a Language Gap, They Fell in Love

Business Insider: 34 most promising AI startups

Time: The Best Inventions of 2024

** Please note that all of our roles will require you to be in-person at our NYC HQ (located in Union Square) **

About the Role:

Captions is seeking an exceptional Research Engineer (MOTS) to advance the state-of-the-art in large-scale multimodal video diffusion models. You'll conduct novel research on generative modeling architectures, develop new training techniques, and scale models to billions of parameters. As a key member of our ML Research team, you'll work at the cutting edge of multimodal generation while building systems that enable natural, controllable video creation. We're already training large-scale models with demonstrated product impact, and we're excited to continue expanding the scope and capabilities of our research.

We're especially excited about pushing the boundaries of audio-video generation, with a focus on realistic and charismatic human behavior that enables natural storytelling and creative iteration. Our models power creative tools used by millions of creators, and we're tackling fundamental challenges in how to generate compelling human motion, expression, and speech. 

Key Responsibilities:

Research & Architecture Development:

• Design and implement novel architectures for large-scale video and multimodal diffusion models

• Develop new approaches to multimodal fusion, temporal modeling, and video control

• Research temporal video editing techniques and controllable generation

• Research and validate scaling laws for video generation models

• Create new loss functions and training objectives for improved generation quality

• Drive rapid experimentation with model architectures and training strategies

• Validate research directly through product deployment and user feedback

Model Training & Optimization:

• Train and optimize models at massive scale (10s-100s of billions of parameters)

• Develop sophisticated distributed training approaches using FSDP, DeepSpeed, Megatron-LM

• Design and implement model surgery techniques (pruning, distillation, quantization)

• Create new approaches to memory optimization and training efficiency

• Research techniques for improving training stability at scale

• Conduct systematic empirical studies of architecture and optimization choices

Technical Innovation:

• Advance state-of-the-art in video model architecture design and optimization

• Develop new approaches to temporal modeling for video generation

• Create novel solutions for multimodal learning and cross-modal align