Audacity Forum

steve wrote:

Gale Andrews wrote:So how exactly did you do that? Why should it be done? What point are you making?

PCM digital audio is always band limited to half the sample rate.

I am sure you know that I know that. I just don't see the relevance of that to your argument. I understand the quantizing part of your argument.

The fact that the hardware may not have a bandwidth of half the sample rate is not relevant to the request (at least the requesters take that view).

Why were "measurements" in microseconds put in as a feature in the first place? Was it a total mistake?

Here is another request (though in this case the user wants four decimal places for seconds): http://forum.audacityteam.org/viewtopic ... 46&t=78182 .


Gale

Gale Andrews wrote:I am sure you know that I know that. I just don't see the relevance of that to your argument. I understand the quantizing part of your argument.

If you only consider the quantizing part, then you might expect the signal in the first image to be quantized like this:
but that is not what happens, (because of the band limiting).

Gale Andrews wrote:The fact that the hardware may not have a bandwidth of half the sample rate is not relevant to the request (at least the requesters take that view).

but it's still pretty meaningless to give measurement units that are several orders more "precise" than the equipment. As an example, there would be no point for an electronic tuner to display pitch to hundredths of a cent, or a wooden ruler with inches marked as 1.000000, 2.000000, 3.000000 ....

Gale Andrews wrote:Here is another request (though in this case the user wants four decimal places for seconds): viewtopic.php?f=46&t=78182 .

I think there is a reasonable case for adding one more decimal place, but where do we draw the line? What if someone requests nanoseconds or picoseconds?

steve wrote:If you only consider the quantizing part, then you might expect the signal in the first image to be quantized like this:


but that is not what happens, (because of the band limiting).

Unfortunately you still have not said how you arrived at this image that "has been band-limited to 48000 Hz":

I assume you are making the point that is how it might "sound"?

steve wrote:

Gale Andrews wrote:The fact that the hardware may not have a bandwidth of half the sample rate is not relevant to the request (at least the requesters take that view).

but it's still pretty meaningless to give measurement units that are several orders more "precise" than the equipment.

So why did we do it before?

Sonic Visualiser has a microseconds resolution. Why?

steve wrote:

Gale Andrews wrote:Here is another request (though in this case the user wants four decimal places for seconds): viewtopic.php?f=46&t=78182 .

I think there is a reasonable case for adding one more decimal place, but where do we draw the line? What if someone requests nanoseconds or picoseconds?

As we have never supported those and no-one has asked for them (yet), we can probably ignore that.

However you must agree that for a track at a mere 1,000,000 Hz you can't object that microseconds are shorter than the sample length.

Gale

Why not user-defined formats, such as e.g. in Excel?
You'd enter a string and the time would be displayed accordingly. There had to be some predefined characters, of course.
For example:
H:M:SS.CSCS (...s)
where H=hours, M=minutes, S=seconds, CS=centi-seconds and s=samples
One placeholder means that the value is only written when there's a non-zero value at this place or in front of it.
00:05:33 --> 5:33
01:00:33 --> 1:00:33
Two characters would always fill up the leading zeros.
The three dots in the parenthesis mean that the samples are displayed for all after seconds, i.e. they skip hours, minutes and seconds.
This could translate 30 min, 12 sec and 22050 samples as
20:12.50 (22050)

We could of course stick to a simpler definition where all placeholders just have their constant cells, e.g.
"H:M:S" gives 00:00:00
Only the value in front is different because it can go higher than normal, i.e. hours would go over 24 when there's no "D" in front.
However, I would like to have different formats at the same time, for instance Pal and Ntsc frames (e.g. "NF <-> PF").
Text or separators could be quoted explicitly or have a indicator in front (such as @).

Robert J. H. wrote:Why not user-defined formats

I've not thought much about the implementation, but user defined formats could include bars, beats and sub-beat divisions, or 4, 5 , 6, 7.... decimal places of a selected unit. Anyone want to generate a tone with a 0.008333333 hour duration?