在iOS中播放自定义.opus音频文件

Per your other comment/question ,如果您可以得到解码的PCM样本,您可以添加一个RIFF/WAV,使用的字节类似于下面的C常量(取自 WAV_HEADER_TEMPLATE )

// Header for a 48 kHz, stereo, 32-bit float WAV.
// http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
static const unsigned char WAV_HEADER_TEMPLATE[44]={
  'R','I','F','F',
  0xFF,0xFF,0xFF,0x7F,  // file size
  'W','A','V','E',
  'f','m','t',' ',      // Chunk ID
  0x10,0x00,0x00,0x00,  // Chunk Size - length of format above
  0x03,0x00,            // Format Code: 1 is PCM, 3 is IEEE float
  0x02,0x00,            // Number of Channels (e.g. 2)
  0x80,0xBB,0x00,0x00,  // Samples per Second, Sample Rate (e.g. 48000)
  0x00,0xDC,0x05,0x00,  // Bytes per second, byte rate = sample rate * bits per sample * channels / 8
  0x08,0x00,            // Bytes per Sample Frame, block align = bits per sample * channels / 8
  0x20,0x00,            // bits per sample (16 for PCM, 32 for float)
  'd','a','t','a',
  0xFF,0xFF,0xFF,0x7F   // size of data section
 };

this C function 也建议阅读。

• 0x01 应用于指定格式代码的PCM
• “数据大小”是解码音频的总字节大小

(完整解决方案: Libopus Kit ) iOS的Swift代码 ( )

guard let url = Bundle.main.url(forResource: "foo", withExtension: "opus") else { return }
print("url: \(url)")

do {
    
    let fileData = try Data(contentsOf: url)
    
    let extractedPCM = AudioUtil.extractPCM(from: fileData, for: OpusAudioSetting(/*defaults*/))
    
    let wavHeader = AudioUtil.createWavHeader(pcmInfo: PCMInfo(/*defaults*/), pcmDataSizeInBytes: Int32(extractedPCM.count))
    //print("wavHeader: \([UInt8](wavHeader))")

    let wavAudioData = AudioUtil.generateWav(header: wavHeader, pcmData: extractedPCM)
    playData(audioData: wavAudioData)
    
    
} catch let error {
    print(error)
}   

音频工具

import Foundation
import OpusKit

public class AudioUtil {

    private init(){}
    
    public static func createWavHeader(pcmInfo: PCMInfo, pcmDataSizeInBytes dataSize: Int32) -> Data {

        let WAV_HEADER_SIZE:Int32 = 44
        let fileSize:Int32 = dataSize + WAV_HEADER_SIZE
        
        let sampleRate:Int32 = 16000
        let subChunkSize:Int32 = 16
        let format:Int16 = 1
        let channels:Int16 = 1
        let bitsPerSample:Int16 = 16
        let byteRate:Int32 = sampleRate * Int32(channels * bitsPerSample / 8)
        let blockAlign: Int16 = (bitsPerSample * channels) / 8
        
        let header = NSMutableData()
        
        header.append([UInt8]("RIFF".utf8), length: 4)
        
        header.append(byteArray(from: fileSize), length: 4)
        
        //WAVE
        header.append([UInt8]("WAVE".utf8), length: 4)
        
        //FMT
        header.append([UInt8]("fmt ".utf8), length: 4)
        header.append(byteArray(from: subChunkSize), length: 4)
        
        header.append(byteArray(from: format), length: 2)
        header.append(byteArray(from: channels), length: 2)
        header.append(byteArray(from: sampleRate), length: 4)
        header.append(byteArray(from: byteRate), length: 4)
        header.append(byteArray(from: blockAlign), length: 2)
        header.append(byteArray(from: bitsPerSample), length: 2)
        
        
        header.append([UInt8]("data".utf8), length: 4)
        header.append(byteArray(from: dataSize), length: 4)
        
        return header as Data
    }

    public static func extractPCM(from audioData: Data, for setting: OpusAudioSetting) -> Data {
        
        OpusKit.shared.initialize(
            sampleRate: setting.sampleRate,
            numberOfChannels: setting.channels,
            packetSize: setting.packetSize,
            encodeBlockSize: setting.encodeBlockSize)
        
        let decodedPCMData = extractAndDecodeAudioData(from: audioData)
        
        return decodedPCMData
    }
    
    public static  func extractAndDecodeAudioData(from fileData: Data, headerSize: Int = 1) -> Data {
      // can not share this implementation
    }
    
    private static func byteArray<T>(from value: T) -> [UInt8] where T: FixedWidthInteger {
        // .littleEndian is required
        return withUnsafeBytes(of: value.littleEndian) { Array($0) }
    }

    public static func generateWav(header wavHeader: Data, pcmData: Data) -> Data {
        
        var wavData = Data()
        
        wavData.append(wavHeader)
        wavData.append(pcmData)
        
        return wavData
    }
}

public struct OpusAudioSetting {
    var sampleRate: opus_int32 = 16000
    var channels: opus_int32 =  1
    var packetSize: opus_int32 = 320
    var encodeBlockSize: opus_int32 = 320
}

public struct PCMInfo {
    var sampleRate:Int32 = 16000
    var channels:Int16 = 1
    var bitsPerSample:Int16 = 16
}