We have an issue with audio recording on i.MX6 Quad Core Platform. The hardware is made by our self (based on SABRESD board), and running Android 4.4.2 (BSP based on android_kk4.4.2_1.0.0-ga).
When the audio source frequency higher than 8 KHz, we can't record any data with our device.
We have confirmed that Microphone can received high frequency (at least 20 KHz) and audio chip (ALC5640) also can record from 8 KHz to 96 KHz data no problem (tested with audio EVB).
The audio chip vendor mention that the limitation may caused by freescale i.MX6, but we have not see any discussion about this topic on support forum.
Have any one have such experience to record high frequency audio on i.MX6 platform? Our requirement is to support 18 KHz~ 20 KHz audio record for audio payment solution.
Our hardware information list on below:
CPU: i.MX6 Quad Core
Audio: Realteak ALC5640-VB
Microphone: Digital Microphone
Android Version: android_kk4.4.2_1.0.0-ga
MCLK : 11289600Hz
BCLK : 1411200Hz
7KHz source is okay
8KHz source is NG