sonic-engine-psx

Disclaimer: I am not the original owner of any songs here, nor of the Psy-Q SDK, nor of Sonic The Hedgehog.

This was built with educational purposes only.

You can play this little game on an online emulator (with an opensource BIOS implementation) on this link.

Building

Build the application's ps-exe:

# Build in debug mode
make BUILD=Debug

# Build in release mode
make

Make sure you have LICENSEA.DAT or equivalent on LCNSFILE directory (this file is not provided here!!!).

Now build the ISO using buildiso.sh, or run the buildshell.sh and run the command:

mkpsxiso -y CDLAYOUT.xml

Cooking audio files

To cook audio files, you need to:

Convert them to .WAV files (with a tool such as ffmpeg);
Convert them to individual .XA files (with psxavenc);
Interleave them in a single .XA file containing up to 4 or 8 different songs (known as channels)
- You MUST use either 4 or 8 files, and set them to null if not used. The number of channels determine the CD-ROM read speed (1x or 2x respectively).

You'll have to execute the buildshell.sh script to start a bash within a Docker container, with tools to build the app.

Should you need extra info, see this link.

Converting files to WAV

ffmpeg -i file.ogg -acodec pcm_s16le -ac 2 -ar 44100 file.wav

Tweak ac to change mono/stereo and -ar to reduce or increase audio quality (here 44.1kHZ is assumed).

Converting WAV to individual XA

# Run this within the build shell
psxavenc -f 37800 -t xa -b 4 -c 2 -F 1 -C 0 file.wav file.xa

Here's how I'd convert a directory full of .WAV files:

for f in *.WAV; do psxavenc -f 37800 -t xa -b 4 -c 2 -F 1 -C 0 "$f" "${f%%.WAV}.XA"; done

Interleaving individual .XA files

First, create a file containing the interleave mapping (e.g. xainterleave.txt). The file layout should look somewhat like this for an individual song:

1 xa file.xa 1 0
1 null
1 null
1 null

In this case, we're building a .XA file with 4 channels, where 3 channels remain unused. Furthermore, using a 1x CD read speed (when playing the song) should suffice.

...or, if you were using two songs:

1 xa file1.xa 1 0
1 xa file2.xa 1 1
1 null
1 null

Notice how we change the channel number for each.

Now interleave the XA:

# Run this within the build shell
xainterleave 1 xainterleave.txt FINAL.XA

That's it. All that remains is adding FINAL.XA to CDLAYOUT.XML so it packs nicely within the ISO.

<file name="FINAL.XA" type="xa" source="FINAL.XA" />

There is a proper tutorial on using .XA here.