Checking the XA file with jPSXdec, It appears that it not only has separate Audio Tracks but also the Video Tracks with audio as well. I kinda assumed that XA files were pretty much just for the audio alone and that STR files can Interleave with XA audio, including multiple audio tracks into one video stream if needed. But I didn't realise it's possible to also store STRs in a multi channel XA file too.
I've tried replicating through MC32/Movie Converter using it's Multi Channel tool to no avail. All I seem to be getting is one second audio files. Tried STR files with and without audio no result. Tried as many options as I could with the multi-channel and MDEC Parameters but it still ends up as a mess.
Anyone through out the years know how this was possibly accomplished? It's mostly out of curiosity but I haven't found any information relating to this. No idea what tools or methods were used.
