Re: 64bit audio read and write

["Måns Rullgård" <mans@mansr.com>]

Matt Flax <flatmax@flatmax.org> writes:

> On 06/07/16 21:41, Måns Rullgård wrote:
>> Matt Flax <flatmax@flatmax.org> writes:
>>
>>> On 06/07/16 17:29, Eric Wong wrote:
>>>> I'm not up-to-date with the latest technology, but even 32-bit
>>>> is far beyond the range of human hearing; and last I checked;
>>>> available ADC/DACs can't even make full use of 24-bit (nor
>>>> our ears).
>>> 120 dB SPL (threshold of discomfort) is around 20 billion times louder
>>> then 20 dB SPL (a whisper). That is approximately 24 bits.
>>> However, we can hear down to 10 dB SPL, or lower for young people ...
>>> that is approximately 40 bits of dynamic range.
>> 120 dB is outright painful and damages the ears.  100 dB is already
>> unpleasant.
>>
>> You should also check your calculations.  With your limits, the required
>> dynamic range would be 110 dB, which comes out to 20 bits with a bit of
>> margin.
>>
> http://www.nal.gov.au/images/diagram-of-noise.jpg
> Anything above 75 dB SPL  has potential to damage your hearing,
> depending on exposure time. The fact that we can hear with clarity
> over such large dynamic range is extraordinary isn't it !

I tend to think it's a natural result of evolution in an environment
where those sound levels occur regularly.

> I think the point I am making is that you can't capture 64 bit words
> of data in audio files with only 32 bit word reads/writes from file. I
> wasn't aware that sox didn't have any methods for 64 bit audio data
> file read and writes. From a pure data perspective, no qualms right ?

Adding support for some file format with 64-bit samples is easy if you
accept truncating the values to 32 bits on read and padding on write.

-- 
Måns Rullgård

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