Video Streaming & Media Delivery Flashcards

In MPEG-DASH, what does the 'MPD' file contain?

Answer: Media Presentation Description with all available representations and segment URLs

The MPD (Media Presentation Description) is DASH's manifest file that describes all available quality representations, segment templates, and timing information.

A sports broadcaster wants to minimize live stream latency to under 3 seconds. Which technology stack best achieves this?

Answer: Low-Latency HLS (LL-HLS) with partial segments

LL-HLS uses partial segments and blocking playlist reloads to achieve sub-3-second latency while maintaining CDN scalability.

What is 'just-in-time packaging' (JIT) in the context of CDN video delivery?

Answer: Segments are transcoded and packaged at the edge only when a viewer requests them

JIT packaging generates adaptive streaming segments on-demand at the CDN edge or origin, eliminating the need to pre-package every format and bitrate.

Which HTTP header is primarily used to instruct CDN edges on whether to cache a video segment and for how long?

Answer: Cache-Control

The Cache-Control header with directives like max-age tells CDN edge nodes how to cache responses and for how long.

A video platform notices that 4K stream requests are frequently missing CDN cache and hitting origin. What is the most likely cause?

Answer: High bitrate variants have low request frequency, reducing cache hit rates

4K content is less popular than lower resolutions, so its segments are requested less frequently, leading to cache evictions and more origin fetches.

What does the term 'glass-to-glass latency' measure in live video streaming?

Answer: Total delay from camera capture to display on the viewer's screen

Glass-to-glass latency measures the end-to-end delay from the moment a camera captures a frame to when it appears on the viewer's display.

Which encoding concept defines the set of bitrate and resolution options offered to an ABR player?

Answer: Bitrate ladder

A bitrate ladder is the predefined set of encoding profiles (bitrate + resolution pairs) from which an ABR player selects based on network conditions.