swift 如果通过 查找音频文件中,出较大音量的时间位置,并从中找出变化较为剧烈的部分,给出时间范围和 另外如何找音量变化最尖锐的部分? 再给出使用 audiokit 处理上述问题的方法,和具体代码
在 Swift 中处理音频文件并查找音量变化较为剧烈的部分,可以使用 AudioKit 这个强大的音频处理库。AudioKit 提供了丰富的音频分析和处理功能,可以帮助你实现这些需求。
首先,确保你已经安装了 AudioKit。你可以使用 Swift Package Manager 或 CocoaPods 来安装。
import AudioKit
import AudioKitEX
import AVFoundation
let fileURL = Bundle.main.url(forResource: "your_audio_file", withExtension: "mp3")!
let audioFile = try! AVAudioFile(forReading: fileURL)
let buffer = AVAudioPCMBuffer(pcmFormat: audioFile.processingFormat, frameCapacity: AVAudioFrameCount(audioFile.length))!
try! audioFile.read(into: buffer)
let channelData = buffer.floatChannelData![0]
let frameLength = Int(buffer.frameLength)
计算音量变化率:
var volumeChanges: [Float] = []
for i in 1..<frameLength {
let volumeChange = abs(channelData[i] - channelData[i - 1])
volumeChanges.append(volumeChange)
}
let maxVolumeChange = volumeChanges.max()!
let maxVolumeChangeIndex = volumeChanges.firstIndex(of: maxVolumeChange)!
let timeAtMaxVolumeChange = Double(maxVolumeChangeIndex) / audioFile.fileFormat.sampleRate
print("Time at max volume change: \(timeAtMaxVolumeChange) seconds")
计算音量变化的导数:
var volumeDerivatives: [Float] = []
for i in 1..<volumeChanges.count {
let derivative = volumeChanges[i] - volumeChanges[i - 1]
volumeDerivatives.append(derivative)
}
let maxDerivative = volumeDerivatives.max()!
let maxDerivativeIndex = volumeDerivatives.firstIndex(of: maxDerivative)!
let timeAtMaxDerivative = Double(maxDerivativeIndex) / audioFile.fileFormat.sampleRate
print("Time at max volume derivative: \(timeAtMaxDerivative) seconds")
import AudioKit
import AudioKitEX
import AVFoundation
func analyzeAudioFile() {
let fileURL = Bundle.main.url(forResource: "your_audio_file", withExtension: "mp3")!
let audioFile = try! AVAudioFile(forReading: fileURL)
let buffer = AVAudioPCMBuffer(pcmFormat: audioFile.processingFormat, frameCapacity: AVAudioFrameCount(audioFile.length))!
try! audioFile.read(into: buffer)
let channelData = buffer.floatChannelData![0]
let frameLength = Int(buffer.frameLength)
var volumeChanges: [Float] = []
for i in 1..<frameLength {
let volumeChange = abs(channelData[i] - channelData[i - 1])
volumeChanges.append(volumeChange)
}
let maxVolumeChange = volumeChanges.max()!
let maxVolumeChangeIndex = volumeChanges.firstIndex(of: maxVolumeChange)!
let timeAtMaxVolumeChange = Double(maxVolumeChangeIndex) / audioFile.fileFormat.sampleRate
print("Time at max volume change: \(timeAtMaxVolumeChange) seconds")
var volumeDerivatives: [Float] = []
for i in 1..<volumeChanges.count {
let derivative = volumeChanges[i] - volumeChanges[i - 1]
volumeDerivatives.append(derivative)
}
let maxDerivative = volumeDerivatives.max()!
let maxDerivativeIndex = volumeDerivatives.firstIndex(of: maxDerivative)!
let timeAtMaxDerivative = Double(maxDerivativeIndex) / audioFile.fileFormat.sampleRate
print("Time at max volume derivative: \(timeAtMaxDerivative) seconds")
}
analyzeAudioFile()
AVAudioFile
加载音频文件。AVAudioPCMBuffer
中,并提取音频样本数据。通过这些步骤,你可以使用 AudioKit 分析音频文件中的音量变化,并找出变化较为剧烈和最尖锐的部分。