Questions about equivalents of audio/video and digital/analog.

Started by August 19, 2007
```Hi:

I=2E Audio vs. Video

Digitized (mono) audio has a single sample per each sampling
interval.

In the case of digital video, we could treat each individual sample
point location in the sampling grid (each pixel position in a frame)
the same way as if it was a sample from an individual (mono) audio
signal that continues on the same position in the next frame. For
example, a 640=D7480 pixel video stream shot at 30 fps would be treated
mathematically as if it consisted of 307200 parallel, individual mono
audio streams [channels] at a 30 Hz sample rate. Where does bit-
resolution enter the equation?

Digital linear PCM audio has the following components:

1=2E	Sample rate [44.1 KHz for CD audio]
2=2E	Channels [2 in stereo, 1 in monaural]
3=2E	Bit-resolution [16-bit for CD audio]

Sample rate in audio =3D frame rate in video
Channel in audio =3D pixel in video
Bit-resolution in audio =3D ? in video

Is it true that unlike the-frequency-of-audio, the-frequency-of-video
has two components -- temporal and spatial?

AFAIK, the-frequency-of-audio only has a temporal component. Do I
guess right?

II. Digital vs. Analog

Sample-rate is a digital entity. In a digital audio device, the sample-
rate must be at least 2x the highest intended frequency of the digital
audio signal. What is the analog-equivalent of sample-rate? In an
analog audio device, does this equivalent need to be at least 2x the
highest intended frequency of the analog audio signal? If not, then
what is the minimum frequency that the analog-equivalent-of-sample-
rate must be in relation to the analog audio signal?

III. My Requests:

No offense but please respond with reasonable answers & keep out the
jokes, off-topic nonsense, taunts, insults, and trivializations. I am
really interested in this.

Thanks for your assistance, cooperation, and understanding,

```
```Radium  <glucegen1@gmail.com> wrote:
>Hi:
>
>I. Audio vs. Video
>
>Digitized (mono) audio has a single sample per each sampling
>interval.
>
>In the case of digital video, we could treat each individual sample
>point location in the sampling grid (each pixel position in a frame)
>the same way as if it was a sample from an individual (mono) audio
>signal that continues on the same position in the next frame. For
>example, a 640&#4294967295;480 pixel video stream shot at 30 fps would be treated
>mathematically as if it consisted of 307200 parallel, individual mono
>audio streams [channels] at a 30 Hz sample rate. Where does bit-
>resolution enter the equation?
>
>Digital linear PCM audio has the following components:
>
>1.	Sample rate [44.1 KHz for CD audio]
>2.	Channels [2 in stereo, 1 in monaural]
>3.	Bit-resolution [16-bit for CD audio]
>
>Sample rate in audio = frame rate in video
>Channel in audio = pixel in video
>Bit-resolution in audio = ? in video
>
>Is it true that unlike the-frequency-of-audio, the-frequency-of-video
>has two components -- temporal and spatial?

No.  Video is converted to a linear data stream corresponding
(roughly) to scan lines.  The color and brightness information
is split apart and converted into parallel data streams.

Compression for digital video may group areas of the image
and/or eliminate some of the color components.

>II. Digital vs. Analog
>
>Sample-rate is a digital entity. In a digital audio device, the sample-
>rate must be at least 2x the highest intended frequency of the digital
>audio signal. What is the analog-equivalent of sample-rate?

There is no sampling in analog so there is no sampling rate.

--
Ray Fischer
rfischer@sonic.net

```
```"Ray Fischer" <rfischer@sonic.net> wrote in message
news:46c8bb30\$0\$14150\$742ec2ed@news.sonic.net...
>>Hi:
>>
>>I. Audio vs. Video
>>
>>Digitized (mono) audio has a single sample per each sampling
>>interval.
>>
>>In the case of digital video, we could treat each individual sample
>>point location in the sampling grid (each pixel position in a frame)
>>the same way as if it was a sample from an individual (mono) audio
>>signal that continues on the same position in the next frame. For
>>example, a 640&#4294967295;480 pixel video stream shot at 30 fps would be treated
>>mathematically as if it consisted of 307200 parallel, individual mono
>>audio streams [channels] at a 30 Hz sample rate. Where does bit-
>>resolution enter the equation?
>>
>>Digital linear PCM audio has the following components:
>>
>>1. Sample rate [44.1 KHz for CD audio]
>>2. Channels [2 in stereo, 1 in monaural]
>>3. Bit-resolution [16-bit for CD audio]
>>
>>Sample rate in audio = frame rate in video
>>Channel in audio = pixel in video
>>Bit-resolution in audio = ? in video
>>
>>Is it true that unlike the-frequency-of-audio, the-frequency-of-video
>>has two components -- temporal and spatial?
>
> No.  Video is converted to a linear data stream corresponding
> (roughly) to scan lines.  The color and brightness information
> is split apart and converted into parallel data streams.
>
> Compression for digital video may group areas of the image
> and/or eliminate some of the color components.
>
>>II. Digital vs. Analog
>>
>>Sample-rate is a digital entity. In a digital audio device, the sample-
>>rate must be at least 2x the highest intended frequency of the digital
>>audio signal. What is the analog-equivalent of sample-rate?
>
> There is no sampling in analog so there is no sampling rate.
>
> --
> Ray Fischer
> rfischer@sonic.net
>

You might want to check into the posting history of

Luck;
Ken

```
```Radium wrote:
> Hi:
>
> I. Audio vs. Video
>
> Digitized (mono) audio has a single sample per each sampling
> interval.

Yes. several bits per sample, many samples per second.

> In the case of digital video, we could treat each individual sample
> point location in the sampling grid (each pixel position in a frame)
> the same way as if it was a sample from an individual (mono) audio
> signal that continues on the same position in the next frame. For
> example, a 640&#65533;480 pixel video stream shot at 30 fps would be treated
> mathematically as if it consisted of 307200 parallel, individual mono
> audio streams [channels] at a 30 Hz sample rate. Where does bit-
> resolution enter the equation?

It might actually make sense to look at it that way in some situations,
but I'll bet you can't think of one. As for bit resolution, what does
that term mean to you? I think it means the number of bits used to
represent each sample, whatever the situation.

> Digital linear PCM audio has the following components:
>
> 1.	Sample rate [44.1 KHz for CD audio]

One particular kind of audio. Common uncompressed audio rates range from
8 to 96 KHz.

> 2.	Channels [2 in stereo, 1 in monaural]

Up to 5 in home theater systems.

> 3.	Bit-resolution [16-bit for CD audio]

So you do know what the term means. Why did you ask then? Easier than
thinking?

> Sample rate in audio = frame rate in video

Bullshit.

> Channel in audio = pixel in video

Bullshit.

> Bit-resolution in audio = ? in video

Bit resolution.

> Is it true that unlike the-frequency-of-audio, the-frequency-of-video
> has two components -- temporal and spatial?

Good question. The signal has a frequency spectrum. A still image has a
spatial spectrum. A video signal represents a series of still images.

> AFAIK, the-frequency-of-audio only has a temporal component. Do I
> guess right?

Yes, until the sound gets into a room. then it has a spatial element
too. Think reflections and standing waves.

> II. Digital vs. Analog
>
> Sample-rate is a digital entity. In a digital audio device, the sample-
> rate must be at least 2x the highest intended frequency of the digital
> audio signal. What is the analog-equivalent of sample-rate? In an
> analog audio device, does this equivalent need to be at least 2x the
> highest intended frequency of the analog audio signal? If not, then
> what is the minimum frequency that the analog-equivalent-of-sample-
> rate must be in relation to the analog audio signal?

There are no samples in an analog system, so there is no sample rate.

> III. My Requests:
>
> No offense but please respond with reasonable answers & keep out the
> jokes, off-topic nonsense, taunts, insults, and trivializations. I am
> really interested in this.

Look, guy: you could probably read by the time you were three years old.
Bully for you! (Precocious reading is almost a /sine qua non/ of
Asperger's.) I have news for you: growing up _doesn't_ mean that one
stops reading. Get a good book or read some of the on-line material
collected at http://www.dspguru.com/ and learn the basics of your
interest. Above all, stop guessing and extrapolating from an erroneous
model that you dreamed up from partial information. You may be smart in
some ways, but if you were wise, you would know that your believing
something doesn't make it real.

As for those snide remarks you want to deflect, you earned them with
but I expect you to shape up.

Jerry
--
Engineering is the art of making what you want from things you can get.
&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;
```
```On Aug 19, 2:50 pm, rfisc...@sonic.net (Ray Fischer) wrote:

> >Hi:

> >I. Audio vs. Video

> >Digitized (mono) audio has a single sample per each sampling
> >interval.

> >In the case of digital video, we could treat each individual sample
> >point location in the sampling grid (each pixel position in a frame)
> >the same way as if it was a sample from an individual (mono) audio
> >signal that continues on the same position in the next frame. For
> >example, a 640=D7480 pixel video stream shot at 30 fps would be treated
> >mathematically as if it consisted of 307200 parallel, individual mono
> >audio streams [channels] at a 30 Hz sample rate. Where does bit-
> >resolution enter the equation?

> >Digital linear PCM audio has the following components:

> >1.  Sample rate [44.1 KHz for CD audio]
> >2.  Channels [2 in stereo, 1 in monaural]
> >3.  Bit-resolution [16-bit for CD audio]

> >Sample rate in audio =3D frame rate in video
> >Channel in audio =3D pixel in video
> >Bit-resolution in audio =3D ? in video

> >Is it true that unlike the-frequency-of-audio, the-frequency-of-video
> >has two components -- temporal and spatial?

> No.  Video is converted to a linear data stream corresponding
> (roughly) to scan lines.  The color and brightness information
> is split apart and converted into parallel data streams.

Okay. So a digital video device with greater bit-resolution can allow
for more levels of luminance?

What is the video-equivalent of bit-resolution?

> Compression for digital video may group areas of the image
> and/or eliminate some of the color components.

Does compression also eliminate some of the brightness components?

> >II. Digital vs. Analog

> >Sample-rate is a digital entity. In a digital audio device, the sample-
> >rate must be at least 2x the highest intended frequency of the digital
> >audio signal. What is the analog-equivalent of sample-rate?

> There is no sampling in analog so there is no sampling rate.

There is no analog-equivalent of sample-rate? Then what the limits the
highest frequency an analog audio device can encode?

What determines the highest frequency signal an analog solid-state
audio device can input without distortion?

Analog solid-state audio device =3D a purely analog electronic device
that can record, store, playback, and process audio signals without
needing any moving parts.

The above device inputs the electrical signals generated by an
attached microphone. These electric signals are AC and represent the
sound in "electronic" form. Sound with a higher-frequency will
generate a faster-alternating current than sound with a lower-
frequency. A louder sound will generate an alternating-current with a
bigger peak-to-peak wattage than a softer soft.

What mathematically determines the highest-frequency electric signal
such a device can intake without distortion?

```
```rfischer@sonic.net (Ray Fischer) wrote:
>>II. Digital vs. Analog
>>
>>Sample-rate is a digital entity. In a digital audio device, the sample-
>>rate must be at least 2x the highest intended frequency of the digital
>>audio signal. What is the analog-equivalent of sample-rate?
>
>There is no sampling in analog so there is no sampling rate.

But that was not the question.  The analog-equivalent is
bandwidth.

In a purely analog channel frequencies higher than the
upper limit of the channel's bandwidth will not be
passed.  When using a digital channel no analog signal
frequencies higher than 1/2 the Nyquist rate (i.e., the
sampling rate) will be passed.

Granted, that with an analog channel the limit is never
a sharply defined frequency; hence in practice there is
not a instant cutoff, but rather a number of negative
effects that become more significant as the signal
frequency approaches and goes beyond the arbitrarily set
"upper limit".  Generally phase distortion increases and
signal level decreases, for example.  The upper limit is
a function of how much distortion is acceptable for the
application.

In a digital channel you cannot pass frequencies higher
1/2 the Nyquist rate, which in theory is a very sharp
cutoff but in practice it becomes very similar to the
gradual analog cutoff.  The reason for that the extreme
negative effects associated with distortion of inputs
that are above that frequency virtually always require
analog filters at the input to absolutely avoid any
frequencies above 1/2 the Nyquist rate.  (Alias
frequencies are generated at the output rather than a
signal which is the same as the input, and the
distortion is 100%. ) Hence analog filters that have the
exact same effects as would be seen with an analog
channel are used at the input of an analog to digital
conversion.

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
```
```On Aug 19, 4:39 pm, Jerry Avins <j...@ieee.org> wrote:

> > In the case of digital video, we could treat each individual sample
> > point location in the sampling grid (each pixel position in a frame)
> > the same way as if it was a sample from an individual (mono) audio
> > signal that continues on the same position in the next frame. For
> > example, a 640?480 pixel video stream shot at 30 fps would be treated
> > mathematically as if it consisted of 307200 parallel, individual mono
> > audio streams [channels] at a 30 Hz sample rate. Where does bit-
> > resolution enter the equation?

> It might actually make sense to look at it that way in some situations,
> but I'll bet you can't think of one.

This would be a start if I want to decrease the frequency of a video
signal without decreasing the playback speed.

The application here is to change the frequency of the video signal
without altering the frame-rate, sample-rate, or tempo of the video
signal.

This is like changing the pitch of audio on playback without modifying
the sample-rate or playback speed.

Using this software, you can also change the tempo of a song without
affecting the pitch.

> As for bit resolution, what does
> that term mean to you? I think it means the number of bits used to
> represent each sample, whatever the situation.

Same here. In audio, a greater bit-resolution provides more levels of
loudness that a smaller bit-resolution. In video, what does a greater
bit-resolution provide that a smaller bit-resolution doesn't? More
levels of light intensity? More colors? I am just guessing.

> > Digital linear PCM audio has the following components:

> > 3. Bit-resolution [16-bit for CD audio]

> So you do know what the term means.

Yes. I know what it means. However, I don't know what its video-
equivalent is?

> > II. Digital vs. Analog
>
> > Sample-rate is a digital entity. In a digital audio device, the sample-
> > rate must be at least 2x the highest intended frequency of the digital
> > audio signal. What is the analog-equivalent of sample-rate? In an
> > analog audio device, does this equivalent need to be at least 2x the
> > highest intended frequency of the analog audio signal? If not, then
> > what is the minimum frequency that the analog-equivalent-of-sample-
> > rate must be in relation to the analog audio signal?

> There are no samples in an analog system, so there is no sample rate.

Okay. Then what is the analog-equivalent of a "sample"?

The analog-equivalent of bit-resolution = dynamic range

The analog-equivalent of sample rate = ?

> http://www.dspguru.com/

```
```Radium wrote:

...

> Okay. So a digital video device with greater bit-resolution can allow
> for more levels of luminance?

Ir color differentiation. Or both.
\
> What is the video-equivalent of bit-resolution?

Bit resolution.

...

> There is no analog-equivalent of sample-rate? Then what the limits the
> highest frequency an analog audio device can encode?

The capabilities of the transmission and recording media.

> What determines the highest frequency signal an analog solid-state
> audio device can input without distortion?

Distortion, in the commonly used sense is immaterial. On a phonograph
disk, high frequencies are limited by the ability of the cutting stylus
to move rapidly, of the playback stylus to stay in the groove at high
acceleration, and of the microphone to capture the sound.

> Analog solid-state audio device = a purely analog electronic device
> that can record, store, playback, and process audio signals without
> needing any moving parts.

Oh? Just what would the record consist of?

> The above device inputs the electrical signals generated by an
> attached microphone. These electric signals are AC and represent the
> sound in "electronic" form. Sound with a higher-frequency will
> generate a faster-alternating current than sound with a lower-
> frequency. A louder sound will generate an alternating-current with a
> bigger peak-to-peak wattage than a softer soft.

All true. How to you record it with no moving parts? Even a microphone
has a moving diaphragm. You must like the taste of your foot. You keep

> What mathematically determines the highest-frequency electric signal
> such a device can intake without distortion?

Distortion (as the term is commonly meant unless otherwise qualified)
entails harmonics which have higher frequencies than that which is
distorted. Near a system's upper frequency limit, harmonic distortion is
impossible. There is no mathematical limit to an analog system's
frequency response; the limit is physical. One can understand purely
digital systems with mathematics alone. Analog systems are messier by
far. You actually have to understand how real-world things behave in
order to deal with them. Purely digital systems have relatively little
use. All of our senses are analog.

Jerry
--
Engineering is the art of making what you want from things you can get.
&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;
```
```Radium wrote:
> On Aug 19, 4:39 pm, Jerry Avins <j...@ieee.org> wrote:
>
>
>>> In the case of digital video, we could treat each individual sample
>>> point location in the sampling grid (each pixel position in a frame)
>>> the same way as if it was a sample from an individual (mono) audio
>>> signal that continues on the same position in the next frame. For
>>> example, a 640?480 pixel video stream shot at 30 fps would be treated
>>> mathematically as if it consisted of 307200 parallel, individual mono
>>> audio streams [channels] at a 30 Hz sample rate. Where does bit-
>>> resolution enter the equation?
>
>> It might actually make sense to look at it that way in some situations,
>> but I'll bet you can't think of one.
>
> This would be a start if I want to decrease the frequency of a video
> signal without decreasing the playback speed.

Various compression schemes do that with varying degrees of resulting
quality.

> The application here is to change the frequency of the video signal
> without altering the frame-rate, sample-rate, or tempo of the video
> signal.
>
> This is like changing the pitch of audio on playback without modifying
> the sample-rate or playback speed.

No it's like compressing the bit rate; MP3, for example.

> Adobe Audition provides this affect.
>
> Using this software, you can also change the tempo of a song without
> affecting the pitch.
>
>> As for bit resolution, what does
>> that term mean to you? I think it means the number of bits used to
>> represent each sample, whatever the situation.
>
> Same here. In audio, a greater bit-resolution provides more levels of
> loudness that a smaller bit-resolution. In video, what does a greater
> bit-resolution provide that a smaller bit-resolution doesn't? More
> levels of light intensity? More colors? I am just guessing.

Both

>>> Digital linear PCM audio has the following components:
>
>>> 3. Bit-resolution [16-bit for CD audio]
>
>> So you do know what the term means.
>
> Yes. I know what it means. However, I don't know what its video-
> equivalent is?
>
>>> II. Digital vs. Analog
>>> Sample-rate is a digital entity. In a digital audio device, the sample-
>>> rate must be at least 2x the highest intended frequency of the digital
>>> audio signal. What is the analog-equivalent of sample-rate? In an
>>> analog audio device, does this equivalent need to be at least 2x the
>>> highest intended frequency of the analog audio signal? If not, then
>>> what is the minimum frequency that the analog-equivalent-of-sample-
>>> rate must be in relation to the analog audio signal?
>
>> There are no samples in an analog system, so there is no sample rate.
>
> Okay. Then what is the analog-equivalent of a "sample"?

There is none.

> The analog-equivalent of bit-resolution = dynamic range
>
> The analog-equivalent of sample rate = ?

Bandwidth.

>> http://www.dspguru.com/
>

Use it. Get facts and stop reasoning from false analogies. If you want
to know how many angels can dance on the head of a pin, build a better
microscope. Aquinas can't tell you, and you can't deduce the answer.

Jerry
--
Engineering is the art of making what you want from things you can get.
&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;
```
```On Aug 19, 5:55 pm, Jerry Avins <j...@ieee.org> wrote:

> > Okay. So a digital video device with greater bit-resolution can allow
> > for more levels of luminance?

> Ir color differentiation. Or both.

Huh?

> > The above device inputs the electrical signals generated by an
> > attached microphone. These electric signals are AC and represent the
> > sound in "electronic" form. Sound with a higher-frequency will
> > generate a faster-alternating current than sound with a lower-
> > frequency. A louder sound will generate an alternating-current with a
> > bigger peak-to-peak wattage than a softer soft.

> All true. How to you record it with no moving parts?

Other than the microphone [obviously], why does there need to be any
moving parts? If a digital audio device can play audio back without
any moving parts, why can't an analog audio device be designed to do
the same?

The device below is *not* analog. It uses sampling so its digital:

http://www.winbond-usa.com/mambo/content/view/36/140/

I'm curious to why there are no purely-analog devices which can
record, store, and playback electric audio signals [AC currents at
least 20 Hz but no more than 20,000 Hz] without having moving parts.
Most of those voice recorders that use chips [i.e. solid-state] are
digital. Analog voice recorders, OTOH, use cassettes [an example of
"moving parts"].

```