This sample program make use of waveInxxxx functions to read from an audio input device like a sound card and write it to a .wav file using mmioxxx functions. It is one of the simplest way to record sound with all the format capabilities supported by the hardware device
Initially, by using waveInGetNumDevs, we can find all the devices and then by using waveInGetDevCaps, we can find the formats it is supported.
To start recording, first select a device and then open the device with waveInOpen API call with the specified format (i.e. 16 bit etc). The output file is also prepared with all the headers filled in properly. Here i am using only PCM format which is easy. If you have more codecs installed on your PC, you can change that one also. But be sure that you supplied the proper values in the WAVEFORMATEX structure.
waveIn needs buffers to start recording. It is better to give more buffers for buffering to avoid any delays. I have used 3 here, but you can add more if your PC needs more time in writing to the HDD and thus causing the delay. Once the buffers are added in the queue, waveInStart will start recording. For each data chunk, the callback function specified in the waveinOpen will get the buffers. Just write it to the file and mark the buffer again for recording by calling the same addbuffer fn.
Once done with recording, adjust the chunk headers using the mmioascend APIs. Thats it.