Re: [linux-audio-user] Linux music editor, greater than 32-bit ?

Rick Wright wrote:
> david wrote:
>
>> Folderol wrote:
>>
>>> On Thu, 22 Feb 2007 13:48:04 -0600
>>> millward <millward@email-addr-hidden> wrote:
>>>
>>>> I've got a sound card capable of 96 bits, ( M-Audio audiofile 24/96 )
>>>> but my sound editor, Audacity for Linux, only goes up to 32 bits.
>>>> Is there a sound editor for Linux that can do higher than 32 bits?
>>>
>>>
>>> Maybe I'm missing something here, but what on earth does anyone need
>>> such high resolution for?
>>>
>>> ISTR The humble CD is recorded at 18bit. which is over 200,000:1 and
>>> more than 100dB. The orchestral dynamic range is I believe quoted at
>>> 90dB. I accept some extra headroom is nice, and the calculations aren't
>>> quite so simple, but even 32bit comes out at mind boggling 200dB.
>>
>>
>> I don't know about such things in the audio world, but in the world of
>> color photography, most professional digital equipment uses 48-bit color
>
> Yes, but this 48bit representation of color is just 16bit x3 colors
> [channels]. In other words the 48bit representation is 3 unrelated
> 16bit [channel] representations concatenated, one each for the 3 primary
> colors/CCD sensors. The equivilent for audio would be just 16bit as
> there is only one channel.

Hmmm, wouldn't there actually be TWO channels for audio - stereo?

>> This is way outside the reproduction range of any photo
>> printing/display technology. But even though a particular 48-bit color
>> might not be printable or displayable, it is still there. It can be
>> taken into consideration when doing color adjustments and image
>> filters. The end result is that when color depth is reduced to the
>> 24-bit color range that JPG uses - you get better and more accurate
>> color reductions.
>>
> Following from above, your final JPG color depth gets reduced to just
> 8bits per color which is why RGB uses values from 0-255. 8bits only has
> informaiton for 256 values.

That's right. But the more information you start with, the smarter the
reduction can be - particularly in areas where the 48-bit color value is
outside the 24-bit dynamic range. In photography, this means the
highlight and shadow areas. In the audio world, would mean this more
accurate renditions in the lowest and highest volume sounds? I don't know.

Depth reduction in color photography doesn't have to be a mindless
simple mathematical calculation, good software like Photoshop
(Windows/Mac) Bibble (Windows/Linux), Raw Therapee (Windows/Linux),
DCRaw (Linux) can do things more intelligently because they have more
information available to them when working with 48-bit color.

I think you can go even higher than 48-bit color in the professional
color world - I think high-end drum scanners scan at 64-bit color.

>> So I would think that working in higher bit-depths for audio would
>> similarly result in better sounding audio when it's reduced to CD format.
>
> This is true, but as Folderol wrote, 32 bits should be *plenty* of
> dynamic range for audio. In fact, it has been argued that ~22bits is
> sufficient as beyond this you get into the h/w noise floor, hearing
> limits, etc.
>
> (Any other experts out there, feel free to jump in if I'm wrong here...)

Yes, experts? I'm no audio engineer!

-- 
David
gnome@email-addr-hidden
authenticity, honesty, community