Browser issues

Because m2c2kit runs within the browser or a webview, it must follow browser constraints. Most relevant for SoundPlayer is the browser's autoplay policy. In brief, the browser requires that the user interact with the page/webview before playing any audio.

In the previous example, you may have noticed this warning in the console:

Play action: audio buffer not ready for sound carHorn (url: assets/docs/sounds/car-horn.mp3); will try next frame

What this means is that SoundPlayer tried to play audio before the browser allowed it. This happened if you pressed the "BEEP" button as the first interaction with the page/webview. The browser will not allow audio playback until the next update (the next frame), which will be approximately 16.7 milliseconds later.

This is not, however, a significant limitation. It is rare for this situation to occur. Usually, an assessment begins with instructions or other scenes that require user interaction. Any interaction with a scene counts as a user interaction with the page/webview, and thus subsequent scenes can immediately play audio.