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OverSampling

Posted: Mon Nov 11, 2013 11:39 am
by Drnkhobo
Hey guys have a look at the 6th post down from this page:

http://synthmaker.co.uk/forum/viewtopic.php?f=4&t=5971&st=0&sk=t&sd=a&hilit=oversampling+toolkit&start=30

Its bootsy's comment and attachment. He says

I've attached an example on how to use straight forward SSE packageing on the 4x Polyphase Upsampler when using two channels


Now if you look at his example, you see the packers & unpackers criss-crossing their 'flow lines' . . . WHY?
Whats the purpose, why not have the first 2 channels of the unpack match up with the first two of the pack?

Anyone have a clue why, or does it not really matter. . ?

Re: OverSampling

Posted: Mon Nov 11, 2013 11:54 am
by KG_is_back
of you follow the packing closely, you can see, that it sorts the samples that channel 1 contains sample1, channel 2 contains next and so on...

Re: OverSampling

Posted: Mon Nov 11, 2013 2:07 pm
by Drnkhobo
Thanks KG, why the need to sort the samples though?

Why do you need to pack the first 2 mono streams into a 'packed' stream, then up sample, then unpack them to pack AGAIN. . ?

thanks for the feedback !

Re: OverSampling

Posted: Tue Nov 12, 2013 1:11 am
by KG_is_back
It is merely a cosmetic thing. it is easier to write oversampled algorithm when you know the samples go in in right order.