やりたいこと

やりたいことはウェブカメラ経由のタイムラプスの撮影で、撮影したファイルはffmpegで読みこませる。そのためファイル名にも要件がある

• foobar-00001.jpg みたいなファイル名にする
• メモリリークしない

swift で書きなおす

xcrun swift で動かせるとスクリプト的に使えて便利なので、そのようにした。特に難しいことはしてないんだけど、やりかたをググっても API がのきなみ古いとかでやる気がなくなる。現時点では最新の方法だが、iOS だと既に deprecated になっているAPIが macOS だと生きていたりするのでややこしい。

#!/usr/bin/xcrun swift
import Darwin
import Cocoa
import AVFoundation

struct ProgramOption {
	var deviceName: String? = nil
	var list: Bool = false
	var help: Bool = false
	var interval: Double = 10
	var format: String = "snapshot-%05d.jpg"
	var sequence: Int = 1
}

var option = ProgramOption()
var args = CommandLine.arguments
while (!args.isEmpty) {
	let arg = args.removeFirst()
	switch arg {
		case "-h", "--help":
			option.help = true
		case "-l", "--list":
			option.list = true
		case "-d", "--device":
			let val = args.removeFirst()
			option.deviceName = val
		case "-i", "--interval":
			let val = args.removeFirst()
			option.interval = Double(val)!
		case "-f", "--format":
			let val = args.removeFirst()
			option.format = val
		case "--start":
			let val = args.removeFirst()
			option.sequence = Int(val)!
		default:
			break
	}
}

if option.help {
	print("Usage: $0 [options]")
	print("  -h --help                     show help")
	print("  -l --list                     list devices")
	print("  -d [name] --device [name]     specify camera device name (default: system default device)")
	print("  -i [num] --interval [num]     specify snapshot interval (default: 10)")
	print("  -f [format] --format [format] specify filename format (default: snapshot-%05d.jpg)")
	print("  --start [num]                 specify start number of sequence")
	exit(0)
}

if option.list {
	let devices = AVCaptureDevice.devices(withMediaType: AVMediaTypeVideo)! as! [AVCaptureDevice]
	for var device in devices {
		print(String(format: "'%@' (%@ %@)", device.localizedName, device.manufacturer, device.modelID))
	}
	exit(0)
}


print("opening capture device")
let device:  AVCaptureDevice
if option.deviceName != nil {
	let devices = AVCaptureDevice.devices(withMediaType: AVMediaTypeVideo)! as! [AVCaptureDevice]

	device = devices.first(where: { (i) in i.localizedName == option.deviceName })!
	print(device)
} else {
	print("using default capture device")
	device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)!
}

let input = try! AVCaptureDeviceInput.init(device: device)
let output = AVCaptureStillImageOutput()

let session = AVCaptureSession()
session.sessionPreset = AVCaptureSessionPresetPhoto
session.addInput(input)
session.addOutput(output)
session.startRunning()

let connection = output.connection(withMediaType: AVMediaTypeVideo)!

let semaphore = DispatchSemaphore(value : 0)
var seq = option.sequence
while (true) {
	output.captureStillImageAsynchronously(
		from: connection,
		completionHandler: { (imageDataBuffer, error) in
			print("captured")
			semaphore.signal()
			if let e = error {
				print(e.localizedDescription)
				return
			}
			if let buffer = imageDataBuffer {
				if let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(buffer) {
					do {
						let filename = String(format: option.format, seq)
						try imageData.write(to: URL.init(fileURLWithPath: filename), options: [])
						seq += 1
						print("wrote to file \(filename)")
					} catch {
						print("failed to write file...")
						exit(1)
					}
				}
			} else {
				print("buffer is empty")
			}
		}
	)

	// output.isCapturingStillImage
	semaphore.wait()

	print("sleep \(option.interval) sec")
	Thread.sleep(forTimeInterval: option.interval)
}