Subject: From: Date:

Re: [ECS] Low modem Record level Don Stephens Sun, 4 Jun 2000 09:59:07 -0700

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Has anyone implemented Dario's code? If so how?

Don
----- Original Message ----- 
From: "Dario Greggio" <adpm.to@inwind.it>
To: <ecs-list@netbloc.com>
Sent: Sunday, June 04, 2000 2:30 AM
Subject: Re: [ECS] Low modem Record level


> Mark Gilmore wrote:
> > 
> > A while back, I spent a lot of time searching for
> > a utility pgm that would add gain to an existing
> > .WAV, but I could never find one that did NOT
> > require some user-interaction.
> > Perhaps one of you could give it a try.
> > If we can find one, I can have ECS execute
> > automatically after recording phone messages.
> 
> Hi Mark, I know you don't like such things written in C, but I'm sending
> it anyway... :-))
> 
> This function takes a bunch of samples (8 bit, mono) "s", whose length
> is "l", and gives you back in a buffer called "d" the samples amplified
> or reduced by "level" (percentage). In fact, level=100 does nothing.
> 
> If you need to start from a WAV file rather than the raw samples, you
> should open the file, move to position following "data" plus 4 bytes
> (I'm attaching a hex dump of a WAV file from my telephone system) and
> from there to EOF execute my function or equivalent.
> 
> BYTE *volWaves(BYTE *s,BYTE *d,DWORD l,int level) {
> register int ch;
> 
> if(level==100)
> return d;
> if(!d)
> d=s;
> while(l--) {
> ch=*s;
> if(ch>=0x80)
> ch=(((ch-0x80)*level)/100)+0x80;
> else
> ch=0x80-(((0x80-ch)*level)/100);
> *d=ch;
> s++;
> d++;
> }
> 
> return d;
>   }
> 
> 
> Hope it helps!
> 
> -- 
> Ciao,
> Dario
> --
> ADPM Synthesis sas - Torino
> --
> http://www.geocities.com/adpm99
> 

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