Handling Video Stitching for Cloudflare Stream: Overcoming ffmpeg Limitations on Vercel

In modern web development, seamlessly serving processed video content to a large audience is increasingly common. However, operational limitations can pose challenges, especially when leveraging serverless platforms like Vercel for media processing tasks. This article explores the issue of concatenating multiple video clips in a serverless environment, specifically focusing on the constraints of running ffmpeg on Vercel and potential strategies to achieve your goals efficiently.

The Scenario

Suppose you’re building a platform where you need to serve short video segments—each around 30 seconds—to a sizable user base, such as 10,000 simultaneous viewers. Your goal is to enhance user experience by combining these segments into a single cohesive video before streaming it via a service like Cloudflare Stream. Doing this on-the-fly can reduce buffering and improve playback smoothness.

The Challenge with Vercel

Vercel is an excellent platform for deploying serverless functions due to its simplicity, scalability, and seamless integration with Next.js. However, it comes with certain limitations—one of the most significant being the inability to run arbitrary native binaries like ffmpeg within serverless functions. This restriction stems from security and infrastructure constraints, making traditional video processing workflows directly on Vercel unfeasible.

Common Approaches and Their Limitations

• Attempting to run ffmpeg within Vercel functions: Due to platform restrictions, ffmpeg isn’t natively supported, preventing on-demand video processing.

• Downloading and processing videos externally: While possible, this approach introduces increased latency, added complexity, and potential cost implications.

• Preprocessing videos: Generating concatenated videos ahead of time doesn’t scale well if your content is dynamic or personalized.

Alternative Strategies

Given these constraints, alternative architectures are necessary to efficiently handle video concatenation for large user bases.

1. External Media Processing Services

Leverage dedicated media processing platforms such as AWS Elastic Transcoder, Azure Media Services, or Google Cloud Video Intelligence. These services support ffmpeg, batch processing, and scalable workflows, allowing you to process and generate concatenated videos ahead of time or on demand outside your main deployment environment.

2. Serverless Functions with Custom Containers

Platforms like Google Cloud Run or AWS Lambda support custom container images, enabling you to include ffmpeg and other binaries within a container. This approach allows for flexible, scalable media processing without relying on platform restrictions