64bit audio read and write

64bit audio read and write

[Matt Flax]

Hi there,

I currently use libsox to load and save audio data. I was wanting to 
write and read 64bit data, however the generic sox sample type is 32 bit 
(from sox.h) :
typedef sox_int32_t sox_sample_t;

The basic format of the read (and write) functions are :
size_t sox_read(
     sox_format_t * ft,
     sox_sample_t *buf,
     size_t len
     );

Can anyone tell me the basic methodology for reading/writing 64bit audio ?

thanks
Matt

------------------------------------------------------------------------------
Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San
Francisco, CA to explore cutting-edge tech and listen to tech luminaries
present their vision of the future. This family event has something for
everyone, including kids. Get more information and register today.
http://sdm.link/attshape

Re: 64bit audio read and write

[Eric Wong]

Matt Flax <flatmax@flatmax.org> wrote:
> Hi there,
> 
> I currently use libsox to load and save audio data. I was wanting to 
> write and read 64bit data, however the generic sox sample type is 32 bit 

Correct, sox does some calculations internally in 64-bit double,
but data which flows in between the effects is all 32-bit int.

> (from sox.h) :
> typedef sox_int32_t sox_sample_t;
> 
> The basic format of the read (and write) functions are :
> size_t sox_read(
>      sox_format_t * ft,
>      sox_sample_t *buf,
>      size_t len
>      );
> 
> Can anyone tell me the basic methodology for reading/writing 64bit audio ?

It would probably reworking a lot of sox internals and would
require increased memory bandwidth, hurting performance for
common <= 32-bit processing.

But, where and how are you working with 64-bit audio
and what 64-bit audio formats are there?

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).


On the other hand, moving to 32-bit float would make sense for
compatibility with 3rd-party plugins (LADSPA for sure, maybe
LV2?).  Right now, we're constantly converting between
float/integer in effects chains which hurts performance.

------------------------------------------------------------------------------
Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San
Francisco, CA to explore cutting-edge tech and listen to tech luminaries
present their vision of the future. This family event has something for
everyone, including kids. Get more information and register today.
http://sdm.link/attshape

Re: 64bit audio read and write

[Matt Flax]

On 06/07/16 17:29, Eric Wong wrote:
> Matt Flax <flatmax@flatmax.org> wrote:
>> Hi there,
>>
>> I currently use libsox to load and save audio data. I was wanting to
>> write and read 64bit data, however the generic sox sample type is 32 bit
> Correct, sox does some calculations internally in 64-bit double,
> but data which flows in between the effects is all 32-bit int.
>
>> (from sox.h) :
>> typedef sox_int32_t sox_sample_t;
>>
>> The basic format of the read (and write) functions are :
>> size_t sox_read(
>>       sox_format_t * ft,
>>       sox_sample_t *buf,
>>       size_t len
>>       );
>>
>> Can anyone tell me the basic methodology for reading/writing 64bit audio ?
> It would probably reworking a lot of sox internals and would
> require increased memory bandwidth, hurting performance for
> common <= 32-bit processing.
>
> But, where and how are you working with 64-bit audio
> and what 64-bit audio formats are there?
I think there are 64 bit file formats, aiff-c perhaps ? Also matlab file 
formats should be supporting 64 bits.
Personally, working with filters and various signal processing 
algorithms like that. It is handy being able to save double length 
words, possibly which are generated and synthesised in one way or other ...

>
> 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.

Actually, I am not proposing we change the bit depth of sox in its 
signal processing system, however perhaps we can introduce functions to 
read and write 64 bit audio ?
Something like functions to read64 and write64 perhaps ?

>
> On the other hand, moving to 32-bit float would make sense for
> compatibility with 3rd-party plugins (LADSPA for sure, maybe
> LV2?).  Right now, we're constantly converting between
> float/integer in effects chains which hurts performance.
>
> ------------------------------------------------------------------------------
> Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San
> Francisco, CA to explore cutting-edge tech and listen to tech luminaries
> present their vision of the future. This family event has something for
> everyone, including kids. Get more information and register today.
> http://sdm.link/attshape
> _______________________________________________
> SoX-devel mailing list
> SoX-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/sox-devel


------------------------------------------------------------------------------
Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San
Francisco, CA to explore cutting-edge tech and listen to tech luminaries
present their vision of the future. This family event has something for
everyone, including kids. Get more information and register today.
http://sdm.link/attshape

Re: 64bit audio read and write

[Måns Rullgård]

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.

-- 
Måns Rullgård

------------------------------------------------------------------------------
Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San
Francisco, CA to explore cutting-edge tech and listen to tech luminaries
present their vision of the future. This family event has something for
everyone, including kids. Get more information and register today.
http://sdm.link/attshape

Re: 64bit audio read and write

[Matt Flax]

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 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 ?

Matt

------------------------------------------------------------------------------
Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San
Francisco, CA to explore cutting-edge tech and listen to tech luminaries
present their vision of the future. This family event has something for
everyone, including kids. Get more information and register today.
http://sdm.link/attshape

Re: 64bit audio read and write

[Måns Rullgård]

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

------------------------------------------------------------------------------
Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San
Francisco, CA to explore cutting-edge tech and listen to tech luminaries
present their vision of the future. This family event has something for
everyone, including kids. Get more information and register today.
http://sdm.link/attshape

Re: 64bit audio read and write

[Jan Stary]

On Jul 06 10:02:34, flatmax@flatmax.org wrote:
> I currently use libsox to load and save audio data. I was wanting to 
> write and read 64bit data, however the generic sox sample type is 32 bit 
> (from sox.h) :
> typedef sox_int32_t sox_sample_t;

If all you need to do is read and write samples,
you might be better off with libsndfile.
http://www.mega-nerd.com/libsndfile/api.html


------------------------------------------------------------------------------