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