What is On-Demand Processing?
On-demand processing creates a media variant only after an application or viewer requests it. Unlike advance generation, it avoids producing outputs that may never be used.
How On-Demand Processing works
On-demand media processing treats a requested transformation specification as the recipe for a derived asset. A cache key normally combines the source identity with normalized operations so equivalent requests reuse one result. The first request enters a queue or worker path, then the completed rendition is stored at an edge or origin for later hits. This pattern fits dynamic resizing, format negotiation, and sparse rendition sets, but it moves capacity planning and failure handling into the request path.
Key facts
- 1Canonicalizing operation order, defaults, dimensions, and format parameters prevents semantically identical requests from fragmenting the derivative cache.
- 2A cache miss can trigger a thundering herd when many viewers request one new variant; request coalescing or generation locks limit duplicate work.
- 3Signed transformation URLs can constrain permitted operations and source objects, reducing the risk that an attacker turns the endpoint into an open compute service.
When On-Demand Processing matters
Use this approach when request patterns are sparse or unpredictable to reduce encoding and storage costs. The tradeoff is added latency and processing risk on the first request for each variant.