GTA IV supports adding custom MP3 files, from which it then creates a radio you can listen to in a car (Independence FM).
This feature has proven to be rather unstable. While the radio may work without problems for some, others may spend hours trying to get it to work without success.

When it comes to its functionality on Linux in Proton, another layer of potential problems is added to all this. Fortunately, getting Independence FM to work is easy.

For some reason, GTA IV uses Windows Media Player (or some of its libraries) to play these MP3 files - not that surprising, considering the entire game was released branded with "Games For Windows Live". Since WMP is not usually a part of a typical default Wine/Proton prefix, it's also not that surprising that it doesn't work.

The following fix should work on desktop PCs as well as on Steam Decks.

To make it work, just install winetricks (should be in the repository of your distribution) and let winetricks install WMP for the specific Wine prefix of GTA IV. It will only exist in this very prefix.


This command runs the winetricks command in the GTA IV prefix (Steam application ID 12210). The path may be different on your machine, but it should always point to "12210/pfx" in "compatdata", regardless of the SteamLibrary in which you've got your GTA installed.

That's usually all you need to do but for the sake of completness, let's go through a few more steps.


MP3s are meant to be stored in the following directory

Just like in case of running the winetricks command, the path may be different in your case but you'll get the idea.


It's unknown to me what are all the accepted formats, it's possible that your existing and untouched MP3s will work just fine but in case of any issues, you can convert them the way I did.

• install Sound Converter ("soundconverter") package from your distro repository
  
• set format to MP3
  
• set bitrate type to VBR
  
• set quality to high
  
• set resampling to 48kHz

No worries, go to "audio" in game settings, re-scan custom songs and set it to "sequential". If it still doesn't work, you may need WMP10 instead because your Wine prefix is most likely a 32 bit one but with all this, you'll most likely figure it out.