Question

我从udp数据包中获取音频PCM 16位Mono数据，如下所示：

(void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data
                                               fromAddress:(NSData *)address
                                         withFilterContext:(id)filterContext
{
...
}

我通过调用swift函数将此数据转换为PCM缓冲区，如下所示：

func toPCMBuffer(data: NSData) -> AVAudioPCMBuffer {
    let audioFormat = AVAudioFormat(commonFormat: AVAudioCommonFormat.PCMFormatFloat32, sampleRate: 8000, channels: 1, interleaved: false)  // given NSData audio format
    var PCMBuffer = AVAudioPCMBuffer(PCMFormat: audioFormat, frameCapacity:1024*10)
    PCMBuffer.frameLength = PCMBuffer.frameCapacity

    let channels = UnsafeBufferPointer(start: PCMBuffer.floatChannelData, count: Int(PCMBuffer.format.channelCount))

    data.getBytes(UnsafeMutablePointer<Void>(channels[0]) , length: data.length)

    return PCMBuffer
}

数据被转换为PCM缓冲区，我可以在日志中看到它的长度。但是当我尝试播放缓冲区时，我听不到任何声音。以下是接收代码：

func toPCMBuffer(data: NSData) -> AVAudioPCMBuffer {
        let audioFormat = AVAudioFormat(commonFormat: AVAudioCommonFormat.PCMFormatFloat32, sampleRate: 8000, channels: 1, interleaved: false)  // given NSData audio format
        var PCMBuffer = AVAudioPCMBuffer(PCMFormat: audioFormat, frameCapacity:1024*10)
        PCMBuffer.frameLength = PCMBuffer.frameCapacity

        let channels = UnsafeBufferPointer(start: PCMBuffer.floatChannelData, count: Int(PCMBuffer.format.channelCount))

        data.getBytes(UnsafeMutablePointer<Void>(channels[0]) , length: data.length)
        var mainMixer = audioEngine.mainMixerNode
        audioEngine.attachNode(audioFilePlayer)
        audioEngine.connect(audioFilePlayer, to:mainMixer, format: PCMBuffer.format)
        audioEngine.startAndReturnError(nil)

        audioFilePlayer.play()
        audioFilePlayer.scheduleBuffer(PCMBuffer, atTime: nil, options: nil, completionHandler: nil)
        return PCMBuffer
    }

Answer 1

最终使用了一个objective-c函数：数据转换得很好

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如何播放从NSData转换而来的AVAudioPCMBuffer的音频

1 个答案: