Add video renderer pool prewarming API #839
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- Add VideoRendererConfiguration public API for prewarming video renderers - Add internal configure method to VideoRendererPool for capacity management - Fix thread safety issue in ReusePool initialization - Eliminates 150-200ms UI hangs when video views are first created
| /// Used for prewarming to add elements beyond initial capacity. | ||
| /// | ||
| /// - Parameter element: The pre-created element to add to the pool. | ||
| func addToAvailable(_ element: Element) { |
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This method defies the Pool's purpose. The pool is responsible for creating its elements on demand.
| /// | ||
| /// - Parameter initialCapacity: The number of video renderers to pre-create. | ||
| @MainActor | ||
| static func configure(initialCapacity: Int) async { |
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This is what is happening on the reusePool initialisation. I don't see a reason for this method.
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The default value is 0: https://github.com/GetStream/stream-video-swift/blob/develop/Sources/StreamVideoSwiftUI/Utils/VideoRendererPool/VideoRendererPool.swift#L20
This entire PR could be removed if that default value is changed, but I didn't want to change the default behavior for all users unexpectedly. So this PR is just a way to expose that number.
| /// // Then later initialize StreamVideo as usual | ||
| /// let streamVideo = StreamVideo(apiKey: apiKey, user: user, token: token) | ||
| /// ``` | ||
| public static func prewarm(count: Int = 2) { |
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This method looks unnecessary. Can you elaborate more on why this is needed and why the existing warm up on init isn't sufficient?
| let element = factory() | ||
| available.append(element) | ||
| // Initialize the pool with a set number of elements (thread-safe) | ||
| queue.sync { |
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Hmm i'm not sure about this one. Even without the sync, there aren't multiple threads accessing the initialiser at the same (if they were they would be creating different instances).
🎯 Goal
Eliminate UI blocking when video renderers are first created during video calls, improving user experience by preventing 150-200ms hangs.
📝 Summary
VideoRendererConfiguration.prewarm()public API for creating video renderers proactivelyReusePoolinitialization🛠 Implementation
New Public API:
Key Implementation Details:
prewarm(count:)method that can be called from any threadawait Task.yield()between each creation to prevent blocking the UI thread for extended periodsReusePool.init()where initial elements were created outside of the thread-safequeue.syncblockaddToAvailable()method toReusePoolfor adding pre-created elements beyond initial capacityTechnical Approach:
🧪 Manual Testing Notes
VideoRendererConfiguration.prewarm(count: 2)early in app lifecycle, then create video call - should see immediate video appearance☑️ Contributor Checklist