Re: long double data type
Re: long double data type
- Subject: Re: long double data type
- From: Jens Alfke <email@hidden>
- Date: Mon, 14 Jun 2010 11:17:01 -0700
On Jun 14, 2010, at 10:58 AM, Luigi Castelli wrote:
> I am working on a DSP audio mastering application that needs to perform mathematical operation at very high resolution.
CoreAudio natively uses 32-bit floats (with 24-bit mantissa) to represent samples. I believe that resolution’s sufficient for even pro apps — Red Book [CD] audio is only 16 bits, and I don’t think even high-end formats use more than 24-bit.
I’m not an expert on FP math, but I don’t know of any float data type supported on Mac OS with more than 64 bits of precision (aka ‘double’).
> Is it a viable choice for a DSP audio application or will I regret it in the long run?
To my knowledge, the vector processing units on x86 only support 32-bit floats. So you wouldn’t be able to vectorize higher-resolution operations, greatly reducing performance. Definitely a consideration if you want to run in real-time.
You might want to ask on the coreaudio-api list, in case anyone has advice on what kind of numeric precision is needed for pro audio work.
—Jens _______________________________________________
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