SDL Audio Device IDs.
Defined in SDL_audio.h
typedef Uint32 SDL_AudioDeviceID;
A successful call to SDL_OpenAudio() is always device id 1, and legacy SDL audio APIs assume you want this device ID. SDL_OpenAudioDevice() calls always returns devices
= 2 on success. The legacy calls are good both for backwards compatibility and when you don't care about multiple, specific, or capture devices.