Some people will convert, some not. Just let people choose. In general, the more possibilities, the more people are happy and UE4 will be more popular. Most users, including my person, use most sounds in MP3 format in Unity and I have never experienced any problem. Also, I have never heard that any user say something against compressed formats. The users that don’t want to use such formats, just don’t use them. We have compressed and non-compressed formats in Unity and really no problem. It’s tha power of Unity that there’s a choice.
The code isn’t the problem, there are still licensing issues with MP3 as far as I know. The license for using MP3 in a game requires you to pay $2,500 per title. mp3 Though it looks like decoding might become patent free soon. Re: MP3 - Wikipedia Licensing and patent issues
Sorry, what I meant was have the Engine automatically handle the conversion. That way the users can still drag-and-drop or import any audio file type, and the engine will convert it on import. That way the engine still treats it as a .wav even though you imported it in another format. I only say this because It might be easier than ensuring that all platforms the engine ships too supports that particular file-type. Most will likely support .mp3 though - I can’t see it being a problem.
The reason nobody says anything about compressed audio formats is because most people, especially developers, know sweet-FA about audio other than how to import it and hook it up. It’s often one of the most overlooked aspects of game development from design to post, something I’d like to see change in the future. I’m one of the lucky few who do since my background before this was Sound Engineering.
EDIT:
Well now… that’s interesting, I always thought MP3 was a totes-free format.
yeah i knew there was some weird licensing that’s why i said mp3 if you can
almost all developers have ears though, they are our primary audio sensors and are usually pretty reliable. you can tell the difference between 24bit wav and an mp3 but you need reasonably good speakers/headphones to hear it, and its so minute it really doesnt make much difference in the end.
i agree audio in games is overlooked way too much. ue4 still has an archaic audio system that even a 1980’s hip hop dj would find basic and outdated. i too have a background in sound so id love to see any improvement over the current system.
A good idea! Now people are lazy and every convenience is always welcomed.
But Unity support this format and I have never heard any problems with MP3 licensing. By the way, it’s really crazy. MP3 is a very popular format and used almost everywhere.
We do have support for FMOD though, which I’ve never used but heard a lot of good things about it. There’s actually A lot of good tolls out there for Audio for Games, and the Engine probably could support all of them relatively easily. No point reinventing the wheel! Though I agree there is room for improvement.
I don’t think he was referring to all the assets you can get from the store. Unity dose not use a proprietary format for all the assets as UE4 dose (I know it imports from a multitude of types but it stores them in .uasset files). Unity uses proprietary formats for the scene (.unity), material (.mat), in editor created animations (.anim), shaders (.shader), animation controllers (.controller), but for models it uses directly the .fbx files, for audio and textures is the same and these files are not bound by copyright, they can be used in any other engine once bought from the Unity Asset Store (read the unity asset store license).
Assets bought from Unity Asset Store must be used as intended inside an application or game and not re-selled. Proprietary files can not be used outside Unity engine, but the other formats (like .fbx, .wav, .png, .jpg) are not bound to Unity engine.
Read 2. END-USER’S RIGHTS AND OBLIGATIONS
http://unity3d.com/legal/as_terms
My bad I forgot that UE4 has a transform gizmo for the selected collision. What I really am missing is to see the transform values for that selected collision in the Details window and be able to set them from keyboard, but for that the Static Mesh Editor would need an Outliner panel to be able to go back to the meshe’s properties. The Outliner panel would give you quick access to the structure of the static mesh (sub objects, collision objects).
MP3 is popular, but a lot of people pay a lot of money to allow MP3 to be used freely on their platforms. So most consumers never notice it.
A quick google search indicates that it is not so straight forward for Unity. On iOS/Android they use Mp3 because Google and Apple have already paid the license for developers. Allowing them to freely use the os’s decoder for it. On Consoles/Mac/PC they use Ogg Vorbis at runtime. They allow any MP3 to be imported and converted behind the scenes in the editor. Odds are they paid the license to allow the editor to function as a decoder to permit the conversion offline, and behind the scenes bake the files into the format needed on the various platform where it’s royalty free (mobile).
Primarly in music and video industry, thats why people think it’s popular, but in game industry you will see more use of ogg or uncompressed PCM to avoid royalties. btw wav is just container that can be compressed to anything including mp3 or ogg, but usally wav is used to contain uncomressed PCM, thats why it’s larger.
Ok, I understand the problem with MP3. In this situation, I think the best solution is making the sound file format converter in Unreal ('s idea). Any type of file can be dragged and converted into wave automatically. In this way, developers won’t use other file types in their projects that do not have clear licenses. Of course, somebody can say why not to convert with using other software (for example, online converters),. It’s true, but I know many users will be happy to see such a feature in Unreal. I am not sure which types should be converted, but for sure MP3. I’m not a specialist in sound technologies, but it would be great to have something like that.
The first found website with sounds:
All the sound in MP3. Unity Developers just download such sounds and use in their projects and nobody think he/she does something wrong.
Here, we can see .wav and .MP3 sounds.
And what with http://www.youtube-mp3.org/. We can get any sound or music legally using this service. I saw a tutorial about UE4 when a man used this service to get sounds from YouTube movie. Then, he converted the MP3 file to .WAV using an online converter.
Of course, I didn’t mean all Unity assets. The proprietary formats shouldn’t be touched. We can make better materials and other things in Unreal. However, non-proprietary assets should be imported to UE4 easily. Almost all is imported without problems. The problem with importing the characters (avatars with bones) that work in Unity well into UE4 refers to the skeleton incompatibility and I see the import frozen at 75%. But human models with Maya-style skeleton seem be imported without problems. But then they should be retargeted manually what is not good. I think Persona should be like Mecanim to detect most bones automatically. And there should be a feature to force the character to be in T-pose. Such a feature is in Mecanim.
While I would like an auto converter for sound files, i think it’s really not important. I already have to convert any texture I want to use to dds because I can’t get it to work right with PNG or JPG, and converting an image is more work than just converting a sound file. I can live with some minutes of extra work 
The situation seems more clear for me now. I have learned much. Thank you for your posts. I will leave the decision what to do with sounds to the Epic Staff. If there are such big problems with MP3 and possibly with other formats, let’s stick to .wav only. All my MP3 Unity sounds will be converted. No problem. I just wished to look at UE4 from the Unity Developer’s point of view. I tried to make UE4 more friendly for Unity users because there are lot of them who think of joining the Epic World and they afraid of complexity and differences.
Anyway, UE4 is a really cool stuff! I will be using it for my projects. Keep working, Guys!
You are right :). The sound conversion isn’t a big problem for me. I can live with that too.
Worth noting that there are batch-converters available too, so you can convert a big folder of assets, and grab a cuppa while it does the boring work for you 
Thank you! It’s very interesting. It would be great to convert a big folder of assets (about 100 GB) automatically. Where can I read more about batch-converters?
Lame seems to make a couple of things, A quick google search gave me a few result. I won’t post them though just in case they’re not what they say they are.
But yeh googling batch convert mp3 to wav yields a lot of results
Sorry, I thought that there was a specific way (function) built in Unreal itself to convert the whole folder of assets (that can be converted of course, without proprietary formats ). But thank you for the idea. When I have a free time, I will look at the Google results about batch-converters.
Now, I’m learning C++ in Unreal because I will need it in my future project. It’s hard to find up to date tuts, but I found one Russian and it will the starting point for me. I can write programs with no problem because I have a long coding experience, but I noticed a few things:
1/ My HUD elements didn’t appear on the scene when I compiled the code. They appeared, when I restarted the UE4 and VS.
2/ Sometimes, the Build button from the Main Menu of UE4 disappears. The Visual Studio Solution User Options file in the folder of my project becomes greyish. I know that I should delete this file and Microsoft Visual Studio Solution file and then generate Visual Studio files again by right click on the Unreal Engine Project file.
3/ Sometimes, the are some dll linking problems that I see in the Output window of VS. I compile again and all great.
4/ My C++ classes don’t appear in the Class Viewer (to make blueprints from them)
here you go
http://audacity.sourceforge/
a half decent and free audio editor with batch conversion