What is the lowest round-trip audio latency achievable with iPhone 4?

Question

What is the lowest input->output audio passthru latency possible with iPhone 4/iOS 4.2? I just want to take input from the mic and play it over the headphones with the smallest delay. I'd like to know the theoretical minimum and minimum actually observed, if possible.

Answer 1

应用程序通常可以44.1k采样率配置长度为256的音频单元RemoteIO输入/记录和输出/播放缓冲区.因此,6至12 mS可能是最低限度,仅从最小的iOS API缓冲区填充/处理延迟(并且不包括操作系统,驱动程序,DAC,放大器,扬声器和空中声速时间)航班延误).