Add avatar expansion in voice chats

submodules/MediaPlayer/Sources/TimeBasedVideoPreload.swift

@@ -0,0 +1,40 @@
+import Foundation
+import UIKit
+import SwiftSignalKit
+import Postbox
+import TelegramCore
+import SyncCore
+import FFMpegBinding
+
+public func preloadVideoResource(postbox: Postbox, resourceReference: MediaResourceReference, duration: Double) -> Signal<Never, NoError> {
+    return Signal { subscriber in
+        let queue = Queue()
+        let disposable = MetaDisposable()
+        queue.async {
+            let maximumFetchSize = 2 * 1024 * 1024 + 128 * 1024
+            //let maximumFetchSize = 128
+            let sourceImpl = FFMpegMediaFrameSource(queue: queue, postbox: postbox, resourceReference: resourceReference, tempFilePath: nil, streamable: true, video: true, preferSoftwareDecoding: false, fetchAutomatically: true, maximumFetchSize: maximumFetchSize)
+            let source = QueueLocalObject(queue: queue, generate: {
+                return sourceImpl
+            })
+            let signal = sourceImpl.seek(timestamp: 0.0)
+            |> deliverOn(queue)
+            |> mapToSignal { result -> Signal<Never, MediaFrameSourceSeekError> in
+                let result = result.syncWith({ $0 })
+                if let videoBuffer = result?.buffers.videoBuffer, let impl = source.syncWith({ $0 }) {
+                    return impl.ensureHasFrames(until: min(duration, videoBuffer.duration.seconds))
+                    |> ignoreValues
+                    |> castError(MediaFrameSourceSeekError.self)
+                } else {
+                    return .complete()
+                }
+            }
+            disposable.set(signal.start(error: { _ in
+                subscriber.putCompletion()
+            }, completed: {
+                subscriber.putCompletion()
+            }))
+        }
+        return disposable
+    }
+}