pitch slide

BlitzMax Forums/BlitzMax Beginners Area/pitch slide

Chris C

(Posted 2005) [#1]

For x#=11025 To 8000 Step -1
Print x#
Print 11025/x#

SetChannelRate(chan,11025.0/x#)

m=MilliSecs()
While MilliSecs()<(m+100)
Wend
Next

just dont do it!
Am I missing somthing or is pitch sliding with max not possible?

BlitzSupport

(Posted 2005) [#2]

You need a much bigger step to hear it change:

sound = LoadSound ("beep.ogg", 1)
Print sound
chan = PlaySound (sound)
For x#=22050 To 8000 Step -500
Print x# 
Print 11025/x# 


SetChannelRate(chan,x#/11025.0) 


m=MilliSecs() 
While MilliSecs()<(m+100) 
Wend 
Next

(I have to admit I'd much prefer if the second parameter was plain old frequency myself.)

Chris C

(Posted 2005) [#3]

frequency would be very nice

the change *Can* be hears but seems v.choppy

now how am i gonna write a tracker...

btw x#/11025 or 11025/x# in your example >:)

ImaginaryHuman

(Posted 2005) [#4]

maybe it's choppy because it changes in too BIG a step, or not often enough? Maybe wait for m+50 and halve the step?

BlitzSupport

(Posted 2005) [#5]

Well, that large step was just to demonstrate the change... just lessen the step!

Chris C

(Posted 2005) [#6]

no its still *really* choppy....

sound = LoadSound ("tada.wav", True)
Print "sound="+sound  ' prints nothing not even   sound=  
chan = PlaySound (sound)

For x#=22000 To 44000 ' very tiny steps
'	Print x#/22000
	SetChannelRate(chan,x#/22000)  ' only seems to work in large steps 
	m=MilliSecs() 
	While MilliSecs()<(m+2) ' a small delay
	Wend 
Next

skidracer

(Posted 2005) [#7]

Yup, I'll fix it first thing next week.

Chris C

(Posted 2005) [#8]

thanks...

Hotcakes

(Posted 2005) [#9]

While you're at it skid, could you implement a SetFreq() command as well? And if you're feeling generous, a SetPeriod() command would be great for oldskool tracker writers...

Nothing people can't do themselves, but to quote someone else 'I bought BlitzMax so I don't have to program' =]

Hotcakes

(Posted 2005) [#10]

In case anybody is interested, the Magic Number for a period/frequency conversion is 7093789.2 for a PAL machine and 7159090.5 for an NTSC machine. Thus :

7093789.2/(period*2)=frequency
7093789.2/frequency/2=period

And www.wotsit.org is a fantastic place for format documentation.

Chris C

(Posted 2005) [#11]

and this is how to load and print out the
contents of the first pattern of a .xm module

' initial release of .xm library
base=LoadBank("corona.xm")
Print "total size"+BankSize(base)
modname:String=getstring(base,17,36)
Print "name:"+modname
tracker:String=getstring(base,38,57)
Print "made with:"+tracker
hs=PeekByte(base,60)+PeekByte(base,61)*256+PeekByte(base,62)*65536+PeekByte(base,63)*16777216
Print "header size:"+hs
hs:+60 ' gives end of header
slen=getword(base,64)
Print "song length:"+slen
restart=getword(base,66)
Print "song restart:"+restart
chans=getword(base,68)
Print "channels:"+chans
pats=getword(base,70)
Print "pattern:"+pats
instrm=getword(base,72)
Print "instruments:"+instrm
flags=getword(base,74)
Print "flags:"+flags
Local s:String
If flags & 1 Then s="Linear " Else s="Amiga "
Print s+"freq table"
tempo=getword(base,76)
Print "tempo:"+tempo
bmp=getword(base,78)
Print "bmp:"+bmp

patheadlen=PeekByte(base,hs)+PeekByte(base,hs+1)*256+PeekByte(base,hs+2)*65536+PeekByte(base,hs+3)*16777216
Print "pattern head length:"+patheadlen

rows=getword(base,hs+5)
Print "rows:"+rows
patsize=getword(base,hs+7)
Print "pattern data size:"+patsize

patbase=hs+9
Print "pattern data start:"+patbase

line:String=""

For l=1 To rows
	For i=1 To chans
	line:+readnote(base,patbase)+" :: "
	Next
Print line
line=""
next

I'd be delighted if some one would add to this as part
of a comunity project.

oops forgot this

'   Period = 10*12*16*4 - Note*16*4 - FineTune/2;
'   Frequency = 8363*2^((6*12*16*4 - Period) / (12*16*4));
' honest guv
Function readnote:String(where,from Var)
Global 	notestr:String[]=["C-","C#","D-","D#","E-","F-","F#","G-","G#","A-","A#","B-"]

	Local s:String,c:Byte,n:Byte
	s=""
	c=PeekByte(where,from)
	from:+1
	If(c&128) Then
		If(c&1)  Then
			n=PeekByte(where,from)-1
			s:+ " N"+notestr[(n Mod 12)]+Byte(n/12)
			from:+1
		Else
			s:+ " "
		EndIf
		If(c&2)  Then
			s:+ " I"+Right(Hex(PeekByte(where,from)),2)
			from:+1
		Else
			s:+ " "
		EndIf
		If(c&4)  Then
			s:+ " V"+Right(Hex(PeekByte(where,from)-16),2)
			from:+1
		Else
			s:+ " "
		EndIf
		If(c&8)  Then 
			s:+ " E"+Right(Hex(PeekByte(where,from)),2)
			from:+1
		Else
			s:+ " "
		EndIf
		If(c&16) Then
			s:+ " D"+Right(Hex(PeekByte(where,from)),2)
			from:+1
		Else
			s:+ " "
		EndIf
	Else 
		s:+ " N"+notestr[(c Mod 12)-1]+Byte(c/12)
		s:+ " I"+Right(Hex(PeekByte(where,from)),2)
		from:+1
		s:+ " V"+Right(Hex(PeekByte(where,from)-16),2)
		from:+1
		s:+ " E"+Right(Hex(PeekByte(where,from)),2)
		from:+1
		s:+ " D"+Right(Hex(PeekByte(where,from)),2)
		from:+1

	EndIf	
	
Return s
EndFunction


Function getword:Int(where,start)
	Return PeekByte(where,start)+PeekByte(where,start+1)*256 
End Function

Function getstring:String(where,start,last)
	Local s:String=""
	For Local x=start To last
		If PeekByte(where,x)<>0 Then s:+Chr(PeekByte(where,x))
		'Print s
	Next
	Return s
End Function

BlitzSupport

(Posted 2005) [#12]

7093789.2/(period*2)=frequency
7093789.2/frequency/2=period

That's interesting, but PCs don't fall into PAL/NTSC categories. I wonder how the number's calculated?

Chris C

(Posted 2005) [#13]

7159090 is twice...ntsc clock value, @ 0.279365ms

28,867 samples/second is also the maximum sampling rate for PAL systems.
Thus, for PAL systems, a value of at least 123 ticks/sample must be
written into the period register.

CLOCK VALUES
NTSC PAL UNITS

Clock Constant 3579545 3546895 ticks per second
Clock Interval 0.279365 0.281937 microseconds per interval

see
http://www.amigarealm.com/computing/knowledge/hardref/ch5.htm
page 137

Hotcakes

(Posted 2005) [#14]

I wonder how the number's calculated?

Most players settle for the NTSC number I think. I guess the fairest method on PC is to just use the average of those two numbers =] There is only one or two 'finetune' values differance between PAL and NTSC, so I guess the average would be no more than 1 finetune value, unless there're really long samples being played (impossible on old .mod format anyway) the differance is negligable.