From ztesic@public.srce.hrMon Dec  1 22:11:42 1997
Date: Sat, 29 Nov 1997 14:17:33 +0100 (MET)
From: zV0nK0 'fC' t3SiC <ztesic@public.srce.hr>
To: digisnap@cs.tu-berlin.de
Subject: more about 32-bit wavs...

> please read docs about IDO and tell me what you think about that!
>I will do it, I hope I find it.

no need to look for it, its inside help file of mod4win :)
just enter help and click on picture of mod4win on that ugly
yellow,green,red
"letter" or something like that... you cannot miss it... all of the docs
about that IDO of theirs are inside...

>Should I include a real peak-search which causes the time for calculating
>to be twice as long?

Well yes, but it should be an option of course (switch).
If you meant to make high quality disk writer to burn modules on CD
it is not important how much will you wait for sampling of one song
because you
do it only once. And for example once when you find out real Peak value
you print
it on screen so user can next time disable peak switch and sample directly
without
peak search because he knows volume value he has to use.

However, I do the peak search now like this... i sample whole file and
look for 0,1% clip, then lower amplitude by one and thats it... :)
little bit slow, real peak search would make it much faster.
In disk mode mod4win 2.4 does real peak search, and it takes for about 2-3
minutes.

I just made 420 Mb file sampled out of my modules :) phew :)

I must also say that your mixing routine does job much better than mod4win
because
those differences in amplitude when you use less channels and all channels
are much
less visible in file sampled by xm2wav than the one sampled by mod4win.
Dunno why, but
it seems so.

>I know that this is the best for post-processing. But I don't know a
>format supporting 24 or 32 bit. So if you have a format description
>I will see what I can do.

You are right, never thought about that. (been away from programming for a
while).
OK, I use cool edit pro. This one can convert to samples to 32 bit, and
save them.
However when saving, only wav format seems to save 32-bit file as it
should be.
I think it is supported by wav (i doubt that cool edit invented own 32-bit
format).

I am including as attachment binary of few versions of wav file, one
16-bit, and another
32-bit. 32 bit wavs are produced with cool edit pro.

...and Raw 16-bit sample data (PCM) for reference... (look with hex editor
in this raw file)
hope that it will help. i will also try to look for wav docs on net and
look for 32-bit wav-s.

I hope i will have time to make stereo and mono files and all of the
stuff...
well.. just look for attachment...

I think that the best thing would be to look on Internet for some
dosc about wav or some RFC or FAQ or something... If I dig something
out about 32bit wavs i'll let you know.

here are just few notes about wavs in attachment.

pc.pcm is 3 word raw mono data, $8001, $0, $7fff (-32767,0,32767)
of course those are normal values in PC raw it looks like $0180,$0,$ff7f
suxx... (btw, i used to code on motorola before there is everything
normal not this lousy intel inverted bytes)

next you have pc.wav - 16bit normal windows wav file, made out of this
pcm raw data

now i can tell you what cool edit says for saving in 32 bit mode...
options for saving of 32-bit floating poing formatting:
1. 24-bit (type 1 -24.0)
2. 32-bit (type 1 -16.8) (should this one be type 2? :)
3. 32-bit (normalized) (type 3 - 0.24)
whatever those mean...

and pc32-1.wav, pc32-2.wav and pc32-3.wav are appropriate files...

hope that this helps at least a little bit...
i think that docs could really be of some help with 32-bit wavs...

however, if you know standard wav structure, you could take a look
on this ones...

ok.. cya...

Zvonko









