Convert a stereo wav to mono in C

Question

I have developed the Synchronous Audio Interface (SAI) driver for a proprietary Real-Time Operating System (RTOS) using C language. My driver is configured to output left and right channel data (I2S) to the amplifier. But, since the amplifier attached is mono, it only outputs left or right channel audio data to the speaker. Now, i have a stereo PCM 16-bit audio data file and i want to somehow mix the left and right channel audio data in my application and send it to either of the left or right channel in the SAI driver. In this way, i will be able to play combined stereo audio data as mono on the speaker attached to the mono amplifier.

Can anyone suggest me that what's the best possible solution to do it?

Answer 1

As said in a comment, the usual way to mix two stereo channels in a mono one is to divide the sample of each channel by 2 and add them.

Example in C like :

int left_channel_sample, right_channel_sample;
int mono_channel = (left_channel_sample / 2) + ( right_channel_sample / 2);

You mentioned some driver you coded, modify it or add some new feature. Can't really help more given the mess of your question...