Audio Engine Updates Preview - Feb 2nd - Live from Epic HQ

[Minus_Kelvin (Aaron McLeran)]

@SmashRash;660262

Thank you for the stream today. I missed the later end of the Q&A so this may have been answered already. I get the feeling the first question is answered by inference but I’m asking anyway.

[QUESTION]: Does the new audio system allow you to ‘get’ from the audio to perhaps determine which audio is playing or more importantly at what point in the audio? Similar to a track I could use to make a media player seek. I may have been doing something more complex than necessary in the past but I remember having to store my own time values so I could create a seek bar that would know both the length of the audio snippet as well as at what point in the time it was playing. I felt that it was not an exact science and I remember it suffering from fractions so if I were to set the audio to play at the same time it was at, unreal engine would have some delay problems or inconsistencies.

Another way to perhaps phrase the same question would be “Will the audio system have functionality at some level compared to a media player?”

Doing our own rendering means that the answer to perhaps every “can we do X” question is YES. But, it’s always just a matter of time. My hope was the system I designed was flexible enough that it’ll be very easy for anybody with modest C++ skills to do some cool stuff in their projects.

Specific to your question, I did create a utility you can use on an audio component to get a BP delegate function on audio playback. This is actually available in the old audio engine but isn’t gauranteed to be accurate on all platforms (only PC) since every platform handles getting this information differently. This is a perfect example of why the old audio engine was such a pain – any feature I make that has any dependency on platforms (which this one does), would have to be done again and again for every platform OR just not work the same on every platform (like I did for this). But this feature does work in the new audio renderer which means it will work for all platforms (eventually when those platform backends are written, which again, is planned for 4.16).

However, in a more general sense – if getting a BP delegate callback isn’t enough and you want ultra-sample accurate timing, you’ll be able to make your own “source effect” in the audio engine, which gives you access to any source’s audio stream. Then you can count the samples and do whatever timing you need. The power will be in your hands!

@SmashRash;660262

[QUESTION] Does the audio system allow for me to bring audio into the project from a designated file directory? I’ve hoped to setup a public sharing folder in a final project that my game player community would be able store and/or drop their personal soundtracks (.wav files) to alter the chosen in-game songs. So a use case would be an in-game MP3 player that would have a set amount of songs but could be easily expanded by a consumer to include their own favorite real-world songs (from real-world musicians) without them having to re-compile and rebuild the project with those resources already in the engine.

I remember exploring non-friendly routes of data streaming and server services to try to get this to function. But to no true or satisfying success.

So you can technically do this now if you know C++ and can write some code in your project. There’s nothing which prevents you from creating your own USoundWave from scratch and feeding it arbitrary audio you personally load from disk. I could make some utilities to allow you to do this more easily in the new synthesis plugin I’m writing and I just might do it. But in general this goes against the UE4 way of asset management and causes potential issues with serialization, etc. It’d be a risky feature that might expose us to more tech-support debt than I’d like.

As for MP3 support, we still don’t support MP3 playback though the legal restrictions are ending at the end of this year I believe so maybe we’ll be able to get MP3 support soon.