Re: Data Types for Extracting samples from Audio Buffer: Resolved

Mon, 06 Oct 2008 07:46:36 -0700 

Graham:

Bingo.....

With
        float *ippointer =  (float *)abl->mBuffers[0].mData;
        float *idpointer =  (float *)abl->mBuffers[1].mData;
        ipbuf = [[NSMutableArray alloc] init];
        idbuf = [[NSMutableArray alloc] init];
        NSNumber* ipsamp = [[NSNumber alloc] init];
        NSNumber* idsamp = [[NSNumber alloc] init];
        nsamples = (abl->mBuffers[0].mDataByteSize)/4;

for (isamp = 0; isamp<nsamples; ++isamp){
                ipsamp = [NSNumber numberWithFloat:(float)ippointer[isamp]];
                     [ipbufaddObject:ipsamp];
                idsamp = [NSNumber numberWithFloat:(float)idpointer[isamp]];
                     [idbufaddObject:idsamp];
        if (isamp < 100) {
                NSLog(@" isamp %d ipsamp %@ idsamp %@",isamp,ipsamp,idsamp);
        }       
}

I get:
2008-10-06 10:43:07.702 Roboplasm[1898:813] isamp 0 ipsamp 0.003356934 idsamp 0.003631592 2008-10-06 10:43:07.702 Roboplasm[1898:813] isamp 1 ipsamp 0.003692627 idsamp 0.004180908 2008-10-06 10:43:07.702 Roboplasm[1898:813] isamp 2 ipsamp 0.004455566 idsamp 0.005157471 2008-10-06 10:43:07.703 Roboplasm[1898:813] isamp 3 ipsamp 0.004394531 idsamp 0.00680542 2008-10-06 10:43:07.703 Roboplasm[1898:813] isamp 4 ipsamp 0.003295898 idsamp 0.00769043 2008-10-06 10:43:07.703 Roboplasm[1898:813] isamp 5 ipsamp 0.002319336 idsamp 0.007324219 2008-10-06 10:43:07.704 Roboplasm[1898:813] isamp 6 ipsamp 0.002227783 idsamp 0.007232666 2008-10-06 10:43:07.705 Roboplasm[1898:813] isamp 7 ipsamp 0.002502441 idsamp 0.008422852 2008-10-06 10:43:07.706 Roboplasm[1898:813] isamp 8 ipsamp 0.002868652 idsamp 0.009490967 2008-10-06 10:43:07.706 Roboplasm[1898:813] isamp 9 ipsamp 0.003631592 idsamp 0.008728027 2008-10-06 10:43:07.706 Roboplasm[1898:813] isamp 10 ipsamp 0.004272461 idsamp 0.007019043 2008-10-06 10:43:07.707 Roboplasm[1898:813] isamp 11 ipsamp 0.004058838 idsamp 0.006469727 2008-10-06 10:43:07.707 Roboplasm[1898:813] isamp 12 ipsamp 0.003112793 idsamp 0.007385254 2008-10-06 10:43:07.707 Roboplasm[1898:813] isamp 13 ipsamp 0.002319336 idsamp 0.008453369 2008-10-06 10:43:07.707 Roboplasm[1898:813] isamp 14 ipsamp 0.002349854 idsamp 0.009155273 2008-10-06 10:43:07.708 Roboplasm[1898:813] isamp 15 ipsamp 0.003295898 idsamp 0.009643555 2008-10-06 10:43:07.708 Roboplasm[1898:813] isamp 16 ipsamp 0.004699707 idsamp 0.009613037 2008-10-06 10:43:07.708 Roboplasm[1898:813] isamp 17 ipsamp 0.005737305 idsamp 0.009124756 2008-10-06 10:43:07.709 Roboplasm[1898:813] isamp 18 ipsamp 0.006103516 idsamp 0.009033203 2008-10-06 10:43:07.709 Roboplasm[1898:813] isamp 19 ipsamp 0.005981445 idsamp 0.009246826 2008-10-06 10:43:07.711 Roboplasm[1898:813] isamp 20 ipsamp 0.005767822 idsamp 0.008728027 2008-10-06 10:43:07.711 Roboplasm[1898:813] isamp 21 ipsamp 0.006011963 idsamp 0.007904053 2008-10-06 10:43:07.712 Roboplasm[1898:813] isamp 22 ipsamp 0.007171631 idsamp 0.00793457 2008-10-06 10:43:07.713 Roboplasm[1898:813] isamp 23 ipsamp 0.008636475 idsamp 0.008300781 2008-10-06 10:43:07.714 Roboplasm[1898:813] isamp 24 ipsamp 0.009216309 idsamp 0.008209229 2008-10-06 10:43:07.715 Roboplasm[1898:813] isamp 25 ipsamp 0.008880615 idsamp 0.008453369 2008-10-06 10:43:07.715 Roboplasm[1898:813] isamp 26 ipsamp 0.008880615 idsamp 0.009552002 2008-10-06 10:43:07.716 Roboplasm[1898:813] isamp 27 ipsamp 0.00982666 idsamp 0.009918213 2008-10-06 10:43:07.717 Roboplasm[1898:813] isamp 28 ipsamp 0.01037598 idsamp 0.008880615 2008-10-06 10:43:07.718 Roboplasm[1898:813] isamp 29 ipsamp 0.009460449 idsamp 0.007843018 2008-10-06 10:43:07.718 Roboplasm[1898:813] isamp 30 ipsamp 0.008148193 idsamp 0.007781982 2008-10-06 10:43:07.719 Roboplasm[1898:813] isamp 31 ipsamp 0.008026123 idsamp 0.007965088 2008-10-06 10:43:07.720 Roboplasm[1898:813] isamp 32 ipsamp 0.00869751 idsamp 0.007965088 2008-10-06 10:43:07.721 Roboplasm[1898:813] isamp 33 ipsamp 0.009124756 idsamp 0.008392334 2008-10-06 10:43:07.722 Roboplasm[1898:813] isamp 34 ipsamp 0.009185791 idsamp 0.009399414 2008-10-06 10:43:07.722 Roboplasm[1898:813] isamp 35 ipsamp 0.00869751 idsamp 0.01043701 2008-10-06 10:43:07.723 Roboplasm[1898:813] isamp 36 ipsamp 0.0078125 idsamp 0.01104736 2008-10-06 10:43:07.724 Roboplasm[1898:813] isamp 37 ipsamp 0.0078125 idsamp 0.01086426 2008-10-06 10:43:07.725 Roboplasm[1898:813] isamp 38 ipsamp 0.009277344 idsamp 0.009918213 2008-10-06 10:43:07.725 Roboplasm[1898:813] isamp 39 ipsamp 0.01062012 idsamp 0.008911133 2008-10-06 10:43:07.726 Roboplasm[1898:813] isamp 40 ipsamp 0.01055908 idsamp 0.008453369 2008-10-06 10:43:07.727 Roboplasm[1898:813] isamp 41 ipsamp 0.01055908 idsamp 0.008117676 2008-10-06 10:43:07.728 Roboplasm[1898:813] isamp 42 ipsamp 0.01177979 idsamp 0.007476807 2008-10-06 10:43:07.728 Roboplasm[1898:813] isamp 43 ipsamp 0.01272583 idsamp 0.007171631 2008-10-06 10:43:07.729 Roboplasm[1898:813] isamp 44 ipsamp 0.012146 idsamp 0.007751465 2008-10-06 10:43:07.730 Roboplasm[1898:813] isamp 45 ipsamp 0.01119995 idsamp 0.008331299 2008-10-06 10:43:07.731 Roboplasm[1898:813] isamp 46 ipsamp 0.01107788 idsamp 0.007873535 2008-10-06 10:43:07.731 Roboplasm[1898:813] isamp 47 ipsamp 0.01092529 idsamp 0.007110596 2008-10-06 10:43:07.732 Roboplasm[1898:813] isamp 48 ipsamp 0.01000977 idsamp 0.007446289 2008-10-06 10:43:07.733 Roboplasm[1898:813] isamp 49 ipsamp 0.009338379 idsamp 0.008605957 2008-10-06 10:43:07.734 Roboplasm[1898:813] isamp 50 ipsamp 0.009490967 idsamp 0.008758545 2008-10-06 10:43:07.735 Roboplasm[1898:813] isamp 51 ipsamp 0.00970459 idsamp 0.007080078 2008-10-06 10:43:07.744 Roboplasm[1898:813] isamp 52 ipsamp 0.01000977 idsamp 0.004852295 2008-10-06 10:43:07.744 Roboplasm[1898:813] isamp 53 ipsamp 0.01141357 idsamp 0.003631592 2008-10-06 10:43:07.745 Roboplasm[1898:813] isamp 54 ipsamp 0.01324463 idsamp 0.003326416 2008-10-06 10:43:07.745 Roboplasm[1898:813] isamp 55 ipsamp 0.01397705 idsamp 0.002838135 2008-10-06 10:43:07.745 Roboplasm[1898:813] isamp 56 ipsamp 0.0138855 idsamp 0.002075195 2008-10-06 10:43:07.746 Roboplasm[1898:813] isamp 57 ipsamp 0.0140686 idsamp 0.001739502 2008-10-06 10:43:07.746 Roboplasm[1898:813] isamp 58 ipsamp 0.01422119 idsamp 0.001403809 2008-10-06 10:43:07.746 Roboplasm[1898:813] isamp 59 ipsamp 0.01397705 idsamp 0.0004577637 2008-10-06 10:43:07.746 Roboplasm[1898:813] isamp 60 ipsamp 0.01394653 idsamp -0.0001220703 2008-10-06 10:43:07.747 Roboplasm[1898:813] isamp 61 ipsamp 0.01403809 idsamp 0.0005187988 2008-10-06 10:43:07.747 Roboplasm[1898:813] isamp 62 ipsamp 0.01364136 idsamp 0.00112915 2008-10-06 10:43:07.747 Roboplasm[1898:813] isamp 63 ipsamp 0.01333618 idsamp 0.0005493164 2008-10-06 10:43:07.752 Roboplasm[1898:813] isamp 64 ipsamp 0.01400757 idsamp -0.0003967285 2008-10-06 10:43:07.754 Roboplasm[1898:813] isamp 65 ipsamp 0.01470947 idsamp -0.0008239746 2008-10-06 10:43:07.754 Roboplasm[1898:813] isamp 66 ipsamp 0.01403809 idsamp -0.00112915 2008-10-06 10:43:07.755 Roboplasm[1898:813] isamp 67 ipsamp 0.01242065 idsamp -0.001617432 2008-10-06 10:43:07.757 Roboplasm[1898:813] isamp 68 ipsamp 0.01098633 idsamp -0.002258301 2008-10-06 10:43:07.757 Roboplasm[1898:813] isamp 69 ipsamp 0.01037598 idsamp -0.00302124 2008-10-06 10:43:07.757 Roboplasm[1898:813] isamp 70 ipsamp 0.01077271 idsamp -0.004089355 2008-10-06 10:43:07.758 Roboplasm[1898:813] isamp 71 ipsamp 0.01229858 idsamp -0.005737305 2008-10-06 10:43:07.758 Roboplasm[1898:813] isamp 72 ipsamp 0.01431274 idsamp -0.0078125 2008-10-06 10:43:07.758 Roboplasm[1898:813] isamp 73 ipsamp 0.01565552 idsamp -0.009185791 2008-10-06 10:43:07.759 Roboplasm[1898:813] isamp 74 ipsamp 0.01574707 idsamp -0.009094238 2008-10-06 10:43:07.759 Roboplasm[1898:813] isamp 75 ipsamp 0.0151062 idsamp -0.008209229 2008-10-06 10:43:07.761 Roboplasm[1898:813] isamp 76 ipsamp 0.01443481 idsamp -0.007568359 2008-10-06 10:43:07.761 Roboplasm[1898:813] isamp 77 ipsamp 0.01391602 idsamp -0.007354736 2008-10-06 10:43:07.762 Roboplasm[1898:813] isamp 78 ipsamp 0.01348877 idsamp -0.007720947 2008-10-06 10:43:07.762 Roboplasm[1898:813] isamp 79 ipsamp 0.01315308 idsamp -0.008880615 2008-10-06 10:43:07.763 Roboplasm[1898:813] isamp 80 ipsamp 0.01275635 idsamp -0.0100708 2008-10-06 10:43:07.764 Roboplasm[1898:813] isamp 81 ipsamp 0.012146 idsamp -0.01049805 2008-10-06 10:43:07.764 Roboplasm[1898:813] isamp 82 ipsamp 0.01168823 idsamp -0.0105896 2008-10-06 10:43:07.765 Roboplasm[1898:813] isamp 83 ipsamp 0.01208496 idsamp -0.01119995 2008-10-06 10:43:07.766 Roboplasm[1898:813] isamp 84 ipsamp 0.01333618 idsamp -0.012146 2008-10-06 10:43:07.766 Roboplasm[1898:813] isamp 85 ipsamp 0.01419067 idsamp -0.0128479 2008-10-06 10:43:07.767 Roboplasm[1898:813] isamp 86 ipsamp 0.0138855 idsamp -0.01358032 2008-10-06 10:43:07.768 Roboplasm[1898:813] isamp 87 ipsamp 0.0133667 idsamp -0.01428223 2008-10-06 10:43:07.768 Roboplasm[1898:813] isamp 88 ipsamp 0.01324463 idsamp -0.01370239 2008-10-06 10:43:07.769 Roboplasm[1898:813] isamp 89 ipsamp 0.01293945 idsamp -0.0118103 2008-10-06 10:43:07.769 Roboplasm[1898:813] isamp 90 ipsamp 0.01257324 idsamp -0.01083374 2008-10-06 10:43:07.770 Roboplasm[1898:813] isamp 91 ipsamp 0.01260376 idsamp -0.01223755 2008-10-06 10:43:07.772 Roboplasm[1898:813] isamp 92 ipsamp 0.01235962 idsamp -0.01419067 2008-10-06 10:43:07.772 Roboplasm[1898:813] isamp 93 ipsamp 0.01116943 idsamp -0.01464844 2008-10-06 10:43:07.773 Roboplasm[1898:813] isamp 94 ipsamp 0.01004028 idsamp -0.01446533 2008-10-06 10:43:07.773 Roboplasm[1898:813] isamp 95 ipsamp 0.009887695 idsamp -0.01516724 2008-10-06 10:43:07.773 Roboplasm[1898:813] isamp 96 ipsamp 0.00994873 idsamp -0.0161438 2008-10-06 10:43:07.774 Roboplasm[1898:813] isamp 97 ipsamp 0.009735107 idsamp -0.0163269 2008-10-06 10:43:07.774 Roboplasm[1898:813] isamp 98 ipsamp 0.009307861 idsamp -0.01629639 2008-10-06 10:43:07.774 Roboplasm[1898:813] isamp 99 ipsamp 0.008300781 idsamp -0.01669312 

This looks like the real thing.

Many thanks,
Joseph

On Oct 6, 2008, at 10:15 AM, Graham Cox wrote:



On 7 Oct 2008, at 12:34 am, Graham Cox wrote:


2008-10-06 09:08:03.109 Roboplasm[33253:813]    format flags            = 41
[]
2008-10-06 09:08:03.111 Roboplasm[33253:813] bits/channel = 32 




format flags = 41 = 0x29 = 0b101001

flags:

enum
{
kAudioFormatFlagIsFloat = (1L << 0), // <------ 1 kAudioFormatFlagIsBigEndian = (1L << 1), // <------ 0 kAudioFormatFlagIsSignedInteger = (1L << 2), // <------ 0 kAudioFormatFlagIsPacked = (1L << 3), // <------ 1 kAudioFormatFlagIsAlignedHigh = (1L << 4), // <------ 0 kAudioFormatFlagIsNonInterleaved = (1L << 5), // <------ 1 
   kAudioFormatFlagIsNonMixable                = (1L << 6),
   kAudioFormatFlagsAreAllClear                = (1L << 31)
};


Thus we have:
kAudioFormatFlagIsFloat | kAudioFormatFlagIsPacked | kAudioFormatFlagIsNonInterleaved;
so you have 32 bit float values for each sample. Divide the byte count by 4 and use [NSNumber numberWithFloat:], and use a float* pointer type.
Note - the docs also state that this is the default format you get from the audio extraction API. 


hth,

Graham


Joseph Ayers, Professor
Department of Biology and
Marine Science Center
Northeastern University
East Point, Nahant, MA 01908
Phone (781) 581-7370 x309(office), x335(lab)
Boston: 444 Richards Hall (617) 373-4044
Cellular (617) 755-7523, FAX: (781) 581-6076
eMail: [EMAIL PROTECTED]
http://www.neurotechnology.neu.edu/






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