                           YM FORMAT PARTICULARITIES
                           =========================


     The YM format is a bit particular. Unlike other soundchips, YM files only 
contain data to be sent to the sound processor. This format has been created by 
Leonard/Oxygene for his Atari soundchip emulator for PC ("ST Sound", and it's 
really a great piece of software). This format is special because it contains 
raw data recorded in direct-to-disk from the original tunes. It isn't very easy 
to explain (moreover in English !), but those who use PaCifiST or ST Sound 
surely know what do I mean.

* How Sound Machine plays an YM music ?

  It depends if the music is LZH packed or not (Sound Machine verifies if the 
header contains the "-lh" string). If there is this header, Sound Machine calls 
LHARCENG.TTP (external LZH unpacker) and you have to indicate a temporary path. 
I know it's not very easy for ST owners who haven't got a hard disk, but contact 
me if you've got a better solution ! Please note you MUST reserve enough memory, 
at least 450 KBytes (click on "Options"), because LHARCENG.TTP needs a lot of 
memory. Sound Machine will then run LHARCENG.TTP by using the right parameters 
("e -mc A:\FILENAME.EXT" if you want to know more about that), and this will 
create a unpacked file in the temporary path. If you don't have a hard disk, you 
should use a RAM disk (at least 400 KBytes) and copy LHARCENG.TTP in it. Indeed, 
Sound Machine will reload LHARCENG.TTP EACH TIME you will load an YM file, so 
just copy it onto your hard disk or RAM disk : it will be faster ! When Sound 
Machine unpacks the file, the buffer is clear, the unpacked file is automatical- 
ly loaded (don't worry, the software remembers the file name and its path) and 
this file is deleted in order to avoid filling your hard disk or RAM disk.
  If the music isn't LZH packed or if it's Ice/Speed/Atomik packed, Sound 
Machine will act like for the others formats.

* Why doesn't it always run ?

  I must admit I've use some strange tricks in order to break the limitations of 
the GFA. But I couldn't kill a vicious bug which kills Sound Machine when you 
want to load and play a second YM music : you will then see the "Error -33" 
message (file not found). I've noted this doesn't happened when I ran Sound 
Machine with a very few numbers of programs in my hard disk's AUTO folder. The 
problem also appears with MagiC but only if you run Sound Machine in multitask 
mode ! Obviously, the solution consists in running the program in monotask mode, 
by pressing the Left Shift key while you double-click the executable file (at 
least with Thing).

* Conclusion

  I've received some LZH depacking routines from Leonard/Oxygene and Frdric 
Dinh but it's in C and assembler... If you have got a GFA routine, please get in 
touch with me !
  Moreover, I've tested Sound Machine with almost all the YM musics on STraTOS 
#4's CD-Rom (directory "CD04\MUSIQUE\YM") and all the musics work perfectly.
  I hope all the "fanatics" of YM music such as Dma Sc and Senser will like 
those new functionalities !  ;-)
