我试图在iOS设备上训练一个CoreML音频分类器,与一些相关的学习资源相比,我遇到了困难。这个音频分类器用于确定一段音乐片段是否与其他歌曲集合相似。因此,分类器的输出只是一个标签,要么是“匹配”,要么是“不匹配”。
使用CreateML应用程序工作流程进行训练非常简单。我只是试图在iOS设备上获得相同类型的训练,但据我所知(如果我错了,请纠正我),iOS不支持CreateML。
我一直在尝试从各种来源中调整代码,以使其在iOS playground中运行。我只能找到关于训练图像分类器的资源,其中以下两个最有帮助 (1, 2)。
请参见我到目前为止想出来的代码如下:
import UIKit
import CoreML
func convertDataToArray<T>(count: Int, data: Data) -> [T] {
let array = data.withUnsafeBytes { (pointer: UnsafePointer<T>) -> [T] in
let buffer = UnsafeBufferPointer(start: pointer, count: count / MemoryLayout<Float32>.size)
return Array<T>(buffer)
}
return array
}
// Get files (names and paths) in directory
public func getAllFilesInDirectory(bundle: Bundle, directory: String, extensionWanted: String) -> (names: [String], paths: [URL]) {
let cachesURL = URL(fileURLWithPath: "/Users/...../Playgrounds/MLPlayground.playground/Resources")
let directoryURL = cachesURL.appendingPathComponent(directory)
do {
try FileManager.default.createDirectory(atPath: directoryURL.relativePath, withIntermediateDirectories: true)
// Get the directory contents urls (including subfolders urls)
let directoryContents = try FileManager.default.contentsOfDirectory(at: directoryURL, includingPropertiesForKeys: nil, options: [])
// Filter the directory contents
let filesPath = directoryContents.filter{ $0.pathExtension == extensionWanted }
let fileNames = filesPath.map{ $0.deletingPathExtension().lastPathComponent }
return (names: fileNames, paths: filesPath);
} catch {
print("Failed to fetch contents of directory: \(error.localizedDescription)")
}
return (names: [], paths: [])
}
let bundle = Bundle.main
var featureProviders = [MLFeatureProvider]()
let matchDir = getAllFilesInDirectory(bundle: bundle, directory: "Match", extensionWanted: "m4a")
let noMatchDir = getAllFilesInDirectory(bundle: bundle, directory: "No Match", extensionWanted: "m4a")
// I have ommited the full path directories for Stack Overflow
try! MLModel.compileModel(at: URL(fileURLWithPath: "/Users/...../Playgrounds/MLPlayground.playground/Resources/UpdateableML.mlmodel"))
let modelDir = URL(fileURLWithPath: "/Users/....../Playgrounds/MLPlayground.playground/Resources/UpdateableML.mlmodel")
let outputDir = URL(fileURLWithPath: "/Users/....../Playgrounds/MLPlayground.playground/Resources/Output/outputmodel.mlmodel")
func getFeatureProvider(forLabel: String, directory: URL) {
let data = try! Data(contentsOf: directory.appendingPathComponent("\(forLabel).m4a"))
// MultiArray (Float32 15600)
let mlInputData = try! MLMultiArray(shape: [15600], dataType: .float32)
let songDataArray: [Float32] = convertDataToArray(count: data.count, data: data)
let count = songDataArray.count
for i in 0..<mlInputData.count {
mlInputData[i] = NSNumber(value: songDataArray[i])
}
let soundValue = MLFeatureValue(multiArray: mlInputData)
let outputValue = MLFeatureValue(string: forLabel)
let dataPointFeatures: [String: MLFeatureValue] = ["audioSamples": soundValue, "classLabel": outputValue]
if let provider = try? MLDictionaryFeatureProvider(dictionary: dataPointFeatures) {
featureProviders.append(provider)
} else {
print("Failed to get provider")
}
}
// Get features
for s in matchDir.names {
getFeatureProvider(forLabel: s, directory: matchDir.paths.first!.deletingLastPathComponent())
}
for s in noMatchDir.names {
getFeatureProvider(forLabel: s, directory: noMatchDir.paths.first!.deletingLastPathComponent())
}
var batchProvider = MLArrayBatchProvider(array: featureProviders)
func updateModel(at url: URL, with trainingData: MLBatchProvider, completionHandler: @escaping (MLUpdateContext) -> Void) {
let updateTask = try! MLUpdateTask(
forModelAt: url,
trainingData: trainingData,
configuration: nil,
completionHandler: completionHandler
)
updateTask.resume()
}
func saveUpdatedModel(_ updateContext: MLUpdateContext) {
let updatedModel = updateContext.model
let fileManager = FileManager.default
do {
try fileManager.createDirectory(
at: outputDir,
withIntermediateDirectories: true,
attributes: nil)
try updatedModel.write(to: outputDir)
print("Updated model saved to:\n\t\(outputDir)")
} catch let error {
print("Could not save updated model to the file system: \(error)")
return
}
}
func updateWith(trainingData: MLBatchProvider, completionHandler: @escaping () -> Void) {
updateModel(at: modelDir, with: trainingData) { context in
print("Update Complete")
saveUpdatedModel(context)
completionHandler()
}
}
updateWith(trainingData: batchProvider, completionHandler: {
print("Final Complete")
})
我目前有两个问题:
- 在 MLUpdateTask 函数 'updateModel' 中,我收到以下错误:
致命错误:'try!' 表达式意外引发错误:Error Domain=com.apple.CoreML Code=0 "无法加载文件 file:///Users/....../Playgrounds/CuratorMLPlayground.playground/Resources/UpdateableML.mlmodel: Error opening file stream: /Users/....../Playgrounds/CuratorMLPlayground.playground/Resources/UpdateableML.mlmodel/coremldata.bin: unspecified iostream_category error"
- 在函数 'getFeatureProvider' 中,我不确定是否正确获取了音频数据,因为 'songDataArray' 的大小约为 260000,但模型/'mlInputData' 的形状是 15600? 请问有人能解释一下吗。
更新: 我已将此复制到我的 iOS 应用程序项目中。现在,在上述错误的位置上出现了以下错误。
Fatal error: 'try!' expression unexpectedly raised an error: Error Domain=com.apple.CoreML Code=0 "Invalid URL for .mlmodel." UserInfo={NSLocalizedDescription=Invalid URL for .mlmodel.}:
然而,我几乎可以确定该URL正确地指向了mlmodel