Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!rutgers!faatcrl!jimb
From: jimb@faatcrl.UUCP (Jim Burwell)
Newsgroups: comp.sys.amiga.audio
Subject: Re: NTModules
Message-ID: <998@faatcrl.UUCP>
Date: 16 Feb 91 04:56:57 GMT
References: <21183@know.pws.bull.com>
Organization: FAA Technical Center, Atlantic City NJ
Lines: 46

C503719@UMCVMB.MISSOURI.EDU (Baird McIntosh) writes:

[...]
>they play at the correct speed as well.  Here's my point:  MED is doing some
>tempo correction for NTSC Amigas, right?  Since MED uses CIA timer A (or B :-)
>I guess it can adjust these things quite easily.

Nope.  The point of using a CIA timer is that you don't have to worry about
video mode.  The video mode doesn't affect a CIA timer.  The vblank interrupt
changes frequency in different video modes.  The PAL screen has more vertical
resolution, therefore vertical blanking (a period in which the electron gun(s)
are turned off [blanked] and the magnetic fields are set up to point the 
electron stream back to the upper left of corner of the screen from the bottom
right) takes longer, making the vertical blank interrupt occur less frequently
under PAL, and more frequently under NTSC.  Hence, the songs go into hi-speed
mode under NTSC.  (vblank on NTSC is every 1/60s and 1/50s under PAL).

>On a final note, for those who claim that 'klisje paa klisje' doesn't play
>right in MED 2.13 (something about the $03 portamento?), I think it does play
>correctly.  I noticed no difference in playing it in MED or Module Master.
>In either program, I notice two instances of 'clicking' in the first half of
>the song... I haven't tried to track this down yet, but I will.

Yes.  In Med 2.13, Portamento is broken.  When you give the portamento command
with a data byte of $00, it is supposed to use the last-used portamento
value.  Med's player routine just sets it to $00, which is a bug.  I've fixed
that in Trackplay, which uses a modified version of modplayer.a which comes
with Med 2.10.

C'ya,
Jim

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