Hello Peti,
1. Unfortunately, I have used a generic and undescriptive name "handle" to identify the audio device that you are using in your program. "audioDevice" would have been a better choice. You have pass this reference to all the waveIn/Out functions so that the operating system knows which audio device you want to work with.
2. My example plays a sound for one second. Either you play this sound 20 times in a for-loop, or you can generate a longer waveform for the entire 20 seconds. In the latter case, you will have to increase the sample buffer sizes and modify the for-loops that generate the signal accordingly.
3. If you want to record waveforms of arbitrary length, you have to figure out where to store the data. One option is to malloc a large memory buffer that you will gradually fill up. You can expand the memory buffer with realloc when necessary, but this will become rather slow as the memory buffer grows larger. Another option is to write the audio data to disk with the TDMS library for high-performance streaming of data.
Main program: create a memory buffer to hold one second of waveform data
create a suspended async timer with a loop rate of 1 second
(async timers give better accuracy than UI timers)
Start button: delete any existing TDMS files with previous recordings (if you want)
open a new TDMS file for recording
resume the async timer
Stop button: suspend the async timer
close the TDMS file
Replay button: reopen the TDMS file
read the audio data from the TDMS file in one second increments
send the data to the audio output device for playback as in my example
Async Callback: retrieve audio input from the audio device as in the example program
append the audio data to a TDMS file
You can find more information about TDMS in samples/TDM Streaming/...
Best regards,
Peter
