Hello Weidong Sun,
1. Yes, demo application records and plays back the audio perfectly. I connect a speaker to the jack and can hear the audio from the Mic.
2. To be specific, I read the data from (Buffer + tx_index*BUFFER_SIZE) where 'Buffer' is (supposedly) a uint8_t array containing the audio data. I then encode it using an encoder. When I decode the encoded data and play it, the the audio is scrambled and I cannot identify any of the microphone data. It is not a problem with the encoding/decoding of the data since I have successfully decoded sample data (in format 16-bit sample) and played it through the speakers fine.
Are you able to confirm where exactly the microphone audio data is stored and in which format? Furthermore, how I can convert it to 16 bit samples? I require the audio data to be in a 16bit array of size 240 (for compatibility with my encoder)
I would be grateful for your help.
Marcus
My code that converts the microphone audio data to an array of 16 bit samples is as follows:
/* Create 16 bit array */
uint16_t * Mic16[240];
/* Capture audio data in 8 bit array */
uint8_t * Mic8= (Buffer + tx_index*BUFFER_SIZE);
/* Copy data from 8 bit array to 16 bit array (note: different endianness for platform) */
for (int i = 0; i < 240; i++)
{
Mic16[i] = ((uint16_t * Mic8++ << 8 );
Mic16[i] |= (uint16_t * Mic8++;
}
/* Encode Mic16*/
/* Decode Mic16*/
