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Z80 driver - 4 channels player with volume control.

Posted: Sun Feb 22, 2009 4:24 pm
by Stef
Lately i had to rewrite my 4ch player Z80 driver as i lost some sources :-/ Wasn't that bad after all as i was capable to improve it and get more "free time" than my first shoot. I have about 48 free slots (/256), a bit less than 20% of Z80 time which is enough to handle some YM2612 or/and PSG command :)

Finally i decided to add volume control with this available time.
I couldn't do more than 16 levels volume control because of Z80 ram limitation. The driver is only handling channel volume for now but i think i can add global volume with the 8 free slots leaving :p

You can download the rom here (the rom name is pl4ch_01.bin)

This driver gimme some ideas as doing a MOD converter : we can build samples at all needed rates and handle ADSR envelop "in software" by adjusting envelop on the fly (once by frame should be ok) X'D

Posted: Sun Feb 22, 2009 4:47 pm
by mic_
You can download the rom here.
The page briefly displays some message in french, then it goes blank and nothing happens.

Re: Z80 driver - 4 channels player with volume control.

Posted: Sun Feb 22, 2009 4:48 pm
by Shiru
Link does not work, empty page.
Stef wrote:we can build samples at all needed rates
No pitch effects then (arpeggio, slides, portamento, vibrato), or you'll need very many samples.

Posted: Sun Feb 22, 2009 4:55 pm
by TmEE co.(TM)
Also cannot get anything :/

Posted: Sun Feb 22, 2009 4:56 pm
by Stef
sorry, i fixed the link !

Re: Z80 driver - 4 channels player with volume control.

Posted: Sun Feb 22, 2009 4:58 pm
by Stef
Shiru wrote:Link does not work, empty page.
Stef wrote:we can build samples at all needed rates
No pitch effects then (arpeggio, slides, portamento, vibrato), or you'll need very many samples.
Does MOD support all that ?? well i suppose i've been optimist :p
anyway we can have a sort of very simple MOD player i guess ;)

Posted: Sun Feb 22, 2009 5:10 pm
by mic_

Posted: Sun Feb 22, 2009 5:16 pm
by Stef
mic_ wrote:
Does MOD support all that ??
http://www.k9spud.com/traxmod/modplayer/effects.php
hmmm ok so MOD won't be that easy ^^

Posted: Sun Feb 22, 2009 5:20 pm
by TmEE co.(TM)
now it works, pretty nice, and quality is very good too :D

Re: Z80 driver - 4 channels player with volume control.

Posted: Sun Feb 22, 2009 5:40 pm
by Shiru
Stef wrote:anyway we can have a sort of very simple MOD player i guess ;)
Yes, but it will barely usable because of many drawbacks:

- It will require to write new music for it (taking all limitations in account)
- To compensate lack of pitch effects longer samples will be needed (takes more memory itself, and much more when duplicated with all pitches)
- Music data will be large anyway
- Not very suitable for games, because no sampled sound effects (or muting music channels, which is sounds bad, or 2-3 channels music, or lower quality of sound to make additional channels for effects)

Re: Z80 driver - 4 channels player with volume control.

Posted: Sun Feb 22, 2009 5:56 pm
by Stef
Shiru wrote:
Stef wrote:anyway we can have a sort of very simple MOD player i guess ;)
Yes, but it will barely usable because of many drawbacks:

- It will require to write new music for it (taking all limitations in account)
- To compensate lack of pitch effects longer samples will be needed (takes more memory itself, and much more when duplicated with all pitches)
- Music data will be large anyway
- Not very suitable for games, because no sampled sound effects (or muting music channels, which is sounds bad, or 2-3 channels music, or lower quality of sound to make additional channels for effects)
True, not very suitable for real use afaik... just a proof of concept :)

Posted: Sun Feb 22, 2009 5:59 pm
by Stef
TmEE co.(TM) wrote:now it works, pretty nice, and quality is very good too :D
Thanks :D
Strangely the quality is better than my first driver which was using similar code at the same output rate :-/

Posted: Sun Feb 22, 2009 8:12 pm
by TmEE co.(TM)
http://www.fileden.com/files/2008/4/21/ ... 4ch_01.rar

a mirror, for people who might get further trouble accessing Stef's link :)

Posted: Mon Feb 23, 2009 2:05 pm
by Stef
Thanks ;)
Unfortunatly i lost my password for my usual FTP so i had to do with this crappy stuff.

Posted: Thu Feb 26, 2009 11:54 pm
by Snake
Stef wrote:
TmEE co.(TM) wrote:now it works, pretty nice, and quality is very good too :D
Thanks :D
Strangely the quality is better than my first driver which was using similar code at the same output rate :-/
:D

I often find I write something better the second time around ;) Probably some bug, typo, or timing error that was too easy to miss.