iAmrSalman/encodeVideo.swift

    // Function to encode the video to MP4 format
    // The function to convert video to MP4
    func encodeVideo(at videoURL: URL, completionHandler: ((URL?, Error?) -> Void)?)  {
        let avAsset = AVURLAsset(url: videoURL, options: nil)
        
        let startDate = Date()
        
        // Create Export session
        guard let exportSession = AVAssetExportSession(asset: avAsset, presetName: AVAssetExportPresetPassthrough) else {
            completionHandler?(nil, nil)
            return
        }
        
        // Creating temp path to save the converted video
        let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0] as URL
        let filePath = documentsDirectory.appendingPathComponent("rendered-Video.mp4")
        
        // Check if the file already exists then remove the previous file
        if FileManager.default.fileExists(atPath: filePath.path) {
            do {
                try FileManager.default.removeItem(at: filePath)
            } catch {
                completionHandler?(nil, error)
            }
        }
        
        exportSession.outputURL = filePath
        exportSession.outputFileType = AVFileType.mp4
        exportSession.shouldOptimizeForNetworkUse = true
        let start = CMTimeMakeWithSeconds(0.0, preferredTimescale: 0)
        let range = CMTimeRangeMake(start: start, duration: avAsset.duration)
        exportSession.timeRange = range
        
        exportSession.exportAsynchronously(completionHandler: {() -> Void in
            switch exportSession.status {
            case .failed:
                print(exportSession.error ?? "NO ERROR")
                completionHandler?(nil, exportSession.error)
            case .cancelled:
                print("Export canceled")
                completionHandler?(nil, nil)
            case .completed:
                // Video conversion finished
                let endDate = Date()
                let time = endDate.timeIntervalSince(startDate)
                print(time)
                print("Successful!")
                print(exportSession.outputURL ?? "NO OUTPUT URL")
                completionHandler?(exportSession.outputURL, nil)
            default: break
            }
        })
    }