Asobo Audio Formats

In addition to the Sound_Z DPC Objects, there are a number of other audio formats supported by FUEL and other Asobo games. The first and least interesting is the .wav Waveform Audio File Format. This format can be read by any standard audio playback tool. The second and considerably more interesting format is the .aif Audio Interchange Format (presumably this is the meaning). Finally and most interestingly, there is the .sdx Sound Archive (also a guess). Instructions on how to open the latter two formats are supplied below.

It is worth noting that the .aif file extension is not unique to Asobo. There is an existing popular audio format developed by Apple in 1988 that uses the extensions .aif, .aiff, and .aifc. The Apple format is distinct from the Asobo format and the two are not interchangeable. This may lead to confusion when researching the format so I wanted to make note of that early on.

An important note is that when a game tries to load an .aif file and the file does not exist, it will fall back to the .wav file with the same name. If neither file exists the sound is not found. This makes audio modding easy since to replace a sound file one does not need to reverse engineer the .aif format. They must only remove/rename the .aif file and replace it with a .wav file with the same name and the game will load that file instead. Since WAVE is a well-known format this is a trivial task.

Finally, FUEL only actually uses the .wav format of the three additional formats listed above. There are no .aif files supplied with the game; however, the game does initially look for the .aif version of each of the .wav files shipped with the game before falling back to the .wav version as described above. There are several .sdx files located in the MUSIC\DIALOG directory. These files contain dialogue from a previous Asobo game, "Sitting Ducks", and are not related to FUEL. Despite the lack of used .aif and .sdx files, the game still appears to have the necessary functionality to load these formats. Because of this, I believe that it is appropriate to document the formats here.

How to play .aif and .sdk files

Step 1: Install foobar2000

Find the "Latest stable version" of foobar2000 for Windows under the downloads page on their website. Download and run the installer. Default settings should be fine.

Step 2: Install the vgmstream component to foobar2000

Find the "foobar2000 component" of vgmstream under Windows on the downloads page on their website. Download the component. The component can be installed to foobar2000 one of two ways. The first way is to double-click on the downloaded component file if foobar2000 is set up to recognize the extension. The alternative way is to open foobar2000 normally and then navigate to the Preferences window. This can be opened from File -> Preferences or by pressing Ctrl-P on your keyboard. Finally, select the Components tab, click the Install... button and select the downloaded component file. You will now need to restart foobar2000.

Step 3: Download the vgmstream TXTH file

This step is only required to open .sdx files not .aif files. Download the .vgmstream.txth file to the directory containing the .sdx files. Make sure the file's name is .vgmstream.txth; the leading period is important, browsers like to remove that period when you download it.

Step 4: Open the files in foobar2000

.aif

To open an .aif file in foobar2000 you must change the extension from .aif to .laif this is because there is another audio format with the extension .aif, as described in the introduction to this entry, and foobar2000 needs the hint to use the Asobo format and not the existing format. Once renamed you can drag and drop the file into foobar2000 to load and play it.

.sdx

To open an .sdx file in foobar2000 you must change the extension from .sdx to .vgmstream this is because foobar2000 does not recognize the .sdx extension but the vgmstream component will load the file with our TXTH file if we rename it; recall that the .vgmstream.txth file must be in the same directory as the .sdx you are trying to open. Once renamed you can drag and drop the file into foobar2000 and it will add all of the sounds in the sound archive to the current playlist. This can get confusing quickly so I recommend creating different playlists to separate the .sdx files.