cog/Audio/ThirdParty/CoreAudioUtils/CoreAudioUtils.m

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/*
* $Id$
*
* Copyright (C) 2006 Stephen F. Booth <me@sbooth.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "CoreAudioUtils.h"
#include <AudioToolbox/AudioFile.h>
// CoreAudio utility function
static NSArray *sAudioExtensions = nil;
// Return an array of valid audio file extensions recognized by Core Audio
NSArray *
getCoreAudioExtensions()
{
OSStatus err;
UInt32 size;
@synchronized(sAudioExtensions) {
if(nil == sAudioExtensions) {
size = sizeof(sAudioExtensions);
err = AudioFileGetGlobalInfo(kAudioFileGlobalInfo_AllExtensions, 0, NULL, &size, &sAudioExtensions);
if(noErr != err) {
return nil;
}
[sAudioExtensions retain];
}
}
return sAudioExtensions;
}
BOOL hostIsBigEndian()
{
#ifdef __BIG_ENDIAN__
return YES;
#else
return NO;
#endif
}
AudioStreamBasicDescription propertiesToASBD(NSDictionary *properties)
{
AudioStreamBasicDescription asbd;
asbd.mFormatID = kAudioFormatLinearPCM;
asbd.mFormatFlags = 0;
asbd.mSampleRate = [[properties objectForKey:@"sampleRate"] doubleValue];
asbd.mBitsPerChannel = [[properties objectForKey:@"bitsPerSample"] intValue];
asbd.mChannelsPerFrame = [[properties objectForKey:@"channels"] intValue];;
asbd.mBytesPerFrame = (asbd.mBitsPerChannel/8)*asbd.mChannelsPerFrame;
asbd.mFramesPerPacket = 1;
asbd.mBytesPerPacket = asbd.mBytesPerFrame;
asbd.mReserved = 0;
if ([[properties objectForKey:@"endian"] isEqualToString:@"big"] || ([[properties objectForKey:@"endian"] isEqualToString:@"host"] && hostIsBigEndian() ))
{
asbd.mFormatFlags |= kLinearPCMFormatFlagIsBigEndian;
asbd.mFormatFlags |= kLinearPCMFormatFlagIsAlignedHigh;
}
if ([[properties objectForKey:@"unsigned"] boolValue] == NO) {
asbd.mFormatFlags |= kLinearPCMFormatFlagIsSignedInteger;
}
return asbd;
}