iOS 音频处理, AVAudioEngine

最新推荐文章于 2023-12-27 16:23:18 发布

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最新推荐文章于 2023-12-27 16:23:18 发布 · 746 阅读

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#ios

本文探讨了iOS中音频处理的两种主要格式ASBD（AudioStreamBasicDescription）和ASPD（AudioStreamPacketDescription）。ASBD用于非压缩音频如wav，而ASPD则用于压缩音频如mp3，其中压缩音频的数据帧不均匀分布。

音频处理的格式有 ASBD ， AudioStreamBasicDescription

和 ASPD, AudioStreamPacketDescription

有 ASPD ，就是压缩音频，例如 mp3

let isCompressed = packetDescriptionsOrNil != nil

没有 ASPD ，就使用 ASBD, 就是非压缩音频，例如 wav

压缩音频，里面的数据不均匀，每个包含有的帧数据不等

func ParserPacketCallback(_ context: UnsafeMutableRawPointer, _ byteCount: UInt32, _ packetCount: UInt32, _ data: UnsafeRawPointer, _ packetDescriptions: Optional<UnsafeMutablePointer<AudioStreamPacketDescription>>) {
    let parser = Unmanaged<Parser>.fromOpaque(context).takeUnretainedValue()
    let packetDescriptionsOrNil: UnsafeMutablePointer<AudioStreamPacketDescription>? = packetDescriptions
    let isCompressed = packetDescriptionsOrNil != nil
    os_log("%@ - %d [bytes: %i, packets: %i, compressed: %@]", log: Parser.loggerPacketCallback, type: .debug, #function, #line, byteCount, packetCount, "\(isCompressed)")
    
    /// At this point we should definitely have a data