avmetrics | Ask WWDC

The session "Discover media performance metrics in AVFoundation" at WWDC 2024 covers various aspects of gathering and utilizing media performance metrics in AVFoundation. Here are some key points from the session:

Introduction of AV Metrics API: In iOS 18, a new AV Foundation API called AV Metrics is introduced. This API provides a unified way to gather metrics from various AV Foundation interfaces. It follows a publisher-subscriber model, allowing apps to subscribe to specific events they are interested in.
Types of Events: The session discusses different types of events such as:
- Likely to Keep Up: Indicates when the AV player has buffered enough to resume playback.
- Summary Events: Provide key performance indicators (KPIs) at the end of a session.
- Stall and Variant Switch Events: Provide information about media playback stalls and variant switches.
- Rate Change Events: Triggered when the playback rate changes.
- Seek Events: Triggered when the user seeks to a different part of the media.
- Error Events: Triggered when an error occurs.
Client-Side Metrics: The session explains how to subscribe to and report client-side metrics to backend analytics servers. This includes creating an AV metric event stream instance, setting a subscriber, and serializing events for backend reporting.
Enhanced Metrics for HLS Streaming: For HLS streaming assets, iOS 18 enhances the available metrics, providing more data points to help diagnose media playback issues.
Practical Example: The session provides a practical example of how to use the AV Metrics API to gather and report metrics such as "likely to keep up" and "summary events" to a backend server.

For more detailed information, you can refer to the specific chapters of the session:

Relevant Sessions

Discover media performance metrics in AVFoundation
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If you have any specific questions or need timestamps for particular topics, feel free to ask!