Downloads the rendered video or a derived asset for the given video_id.

Aligns with the
OpenAI Retrieve video content
contract: optional query variant selects video (default MP4), thumbnail, or spritesheet.

Parameters and response vary by provider. Supported variant values, media types, and availability of
preview assets depend on the upstream provider and model behind the job. In practice, almost all video models
return the primary video asset; thumbnail and spritesheet may be unavailable or return
different content types for some providers.

The response body is binary; Content-Type reflects the actual media type. Upstream may stream the body.

Tool calling and prompt/context caching are supported when the provider and model used to create the job
expose those capabilities (check model info for supports_function_calling and supports_prompt_caching).