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Article #2147recording from DSP problems
From: Lo Shih
Date: Sat, 19 Dec 1992 04:10
Date: Sat, 19 Dec 1992 04:10
78 lines
2550 bytes
2550 bytes
We are building a Sound App and we're having problems recording
from the DSP. We're using a MetaResearch Digital Ears to sample
our sound into the Next standard Sound structure.
We know that the Digital Ears works because we can issue a "sndrecord -d"
command from the terminal with success.
We're setting the data format of our Sound to SND_FORMAT_DSP_DATA_16
when recording and changing the data format to SND_FORMAT_LINEAR_16
when playing (which is recommended by the GeneralRef/AppKit docs).
We know that we've filled the Sound struct with some data. We get a
logical value for duration sampleCount and dataSize.
However, when we send the sound a play message, nothing is played
and an error code "18" is returned. We put some of our code at the
end of this article.
Please help us if you can.
- Lo Shih
- Chris Miller
our code:
- record:sender
{
/*
* If ready, initialize the sound struct and record
*/
if ([theSound status] == NX_SoundStopped) {
[self setSoundSize];
sndError = [theSound record];
[self printError];
}
return self;
}
- setSoundSize
{
/*
* if the NXRadio is on MIC then record from microphone
* otherwise record from the DSP
*/
if ([micRadio state]) {
[theSound setDataSize:(int)9000000
dataFormat:(int)SND_FORMAT_MULAW_8
samplingRate:(int)SND_RATE_CODEC
channelCount:(int)1
infoSize:(int)4];
}
else {
[theSound setDataSize:(int)9000000
dataFormat:(int)SND_FORMAT_DSP_DATA_16
samplingRate:(int)SND_RATE_HIGH
channelCount:(int)2
infoSize:(int)4];
}
}
- play:sender
{
if (([theSound status] == NX_SoundStopped) ||
([theSound status] == NX_SoundPlayingPaused)) {
if (![theSound isPlayable]) {
[theSound convertToFormat:(int)SND_FORMAT_LINEAR_16];
}
sndError = [theSound play];
[self printError];
}
return self;
}
Technical Details
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Newsgroups: comp.sys.next.programmer
Path: arc1-ca.pugleaf.net!sparky!uunet!caen!dmno
From: dmno@math.lsa.umich.edu (Lo Shih)
Subject: recording from DSP problems
Message-ID: <SbV=wG=@engin.umich.edu>
Date: Fri, 18 Dec 92 23:10:27 EST
Organization: University of Michigan, Mathematics Department, Ann Arbor
Sender: Lo Shih and Chris Miller, {lfo}{ff}
Distribution: comp.sys.next.programmer
Keywords: DSP, Sound, record, IB, AppKit
Nntp-Posting-Host: winterpark.math.lsa.umich.edu
Lines: 79