[Radium[_4_]]

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 640×480 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?

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

[Ray Fischer]

Radium 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 640×480 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

[Ken Maltby]

"Ray Fischer" wrote in message
...
Radium 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 640×480 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



You might want to check into the posting history of
"Radium".

Luck;
Ken

[Jerry Avins]

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�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

Bull****.

Channel in audio = pixel in video

Bull****.

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
your pig-headed pursuit of arrant nonsense. I'm willing to start over,
but I expect you to shape up.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Radium[_4_]]

On Aug 19, 2:50 pm, (Ray Fischer) wrote:

Radium 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 640×480 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.

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 = 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?

[Floyd L. Davidson]

(Ray Fischer) wrote:
Radium 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
Ukpeagvik (Barrow, Alaska)

[Radium[_4_]]

On Aug 19, 4:39 pm, Jerry Avins wrote:

Radium 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.

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.

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/

Thanks for the link

[Jerry Avins]

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
putting it in your mouth.

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.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Jerry Avins]

Radium wrote:
On Aug 19, 4:39 pm, Jerry Avins wrote:

Radium 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/

Thanks for the link

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.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Radium[_4_]]

On Aug 19, 5:55 pm, Jerry Avins wrote:

Radium 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"].

[Radium[_4_]]

On Aug 19, 6:08 pm, Jerry Avins wrote:

Radium wrote:

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.

I am talking about:

1. Decreasing the temporal frequency of the video signal without low-
pass filtering or decreasing the playback speed - an example of which
would be decreasing the rate at which a bird [in the movie] flaps its
wings. Hummingbirds flap their wings too fast for the human eye to
see. So the flap-rate of the wings could be decreased until the
flapping is visible to the human eye - without decreasing the playback
speed of the video. This decrease in flap-rate without slowing
playback is visually-analogous to decreasing the pitch of a recorded
sound without decreasing the playback speed. In this case, low-pass
filter would involve attenuating rapidly-changing images while
amplifying slowly-changing images -- I don't want this.

2. Decreasing the spatial frequency of the images in the video-signal
without low-pass filtering the images or increasing their sizes. An
example of this would be making the sharp areas of an image look
duller without decreasing the "sharpness" setting [an example of low-
pass filtering] on the monitor or increasing the size of the image.
Normally, when the size of an image is decreased, its sharpness
increases [it's like compressing a lower-frequency sound wave into a
higher-frequency one]. Likewise, when the size of an image is
increased, it looks duller [like stretching a higher-frequency sound
wave into a lower-frequency one]. Low-pass filtering simply decreasing
the sharpness of an image while increasing its dull characteristics --
which is what I don't want.

#1 Decreases the rate at which objects in the video move without
decreasing the video's playback speed or eliminating originally-
rapidly-moving objects [such as the rapidly flapping wings]

#2 Decreases makes a still image less sharp by stretching everything
within the image without increasing the size of the image or
eliminating sharp portions of the original image

Both #1 and #2 are visual-equivalents of decreasing the pitch of a
recorded audio signal without decreasing the audio's playback speed.

[Jerry Avins]

Radium wrote:
On Aug 19, 5:55 pm, Jerry Avins wrote:

...

Ir color differentiation. Or both.

Huh?

Typo: Or color differentiation. Or both.

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?

Describe a motion-free process of recording and playing back. Cutting
grooves on a disk or magnetizing a moving tape both involve motion.

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"].

It's this simple: nobody has invented a way. I doubt than anyone ever
will. If you know how, communicate with me privately. With your idea and
my ability to bring it to fruition, we'll both get rich. A motion-free
method for printing text would also be a money maker.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Jerry Avins]

Radium wrote:
On Aug 19, 6:08 pm, Jerry Avins wrote:

Radium wrote:

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.

I am talking about:

1. Decreasing the temporal frequency of the video signal without low-
pass filtering or decreasing the playback speed - an example of which
would be decreasing the rate at which a bird [in the movie] flaps its
wings. Hummingbirds flap their wings too fast for the human eye to
see. So the flap-rate of the wings could be decreased until the
flapping is visible to the human eye - without decreasing the playback
speed of the video. This decrease in flap-rate without slowing
playback is visually-analogous to decreasing the pitch of a recorded
sound without decreasing the playback speed. In this case, low-pass
filter would involve attenuating rapidly-changing images while
amplifying slowly-changing images -- I don't want this.

You convinced me: there are stupid questions. Video and movies work by
displaying a succession of still pictures close enough together in time
and and position to give us the illusion of continuous motion. Think
about how slow motion is accomplished with film photography. Speculate
about how this might be done with analog video, and extrapolate to
digitized video.

2. Decreasing the spatial frequency of the images in the video-signal
without low-pass filtering the images or increasing their sizes. An
example of this would be making the sharp areas of an image look
duller without decreasing the "sharpness" setting [an example of low-
pass filtering] on the monitor or increasing the size of the image.
Normally, when the size of an image is decreased, its sharpness
increases [it's like compressing a lower-frequency sound wave into a
higher-frequency one]. Likewise, when the size of an image is
increased, it looks duller [like stretching a higher-frequency sound
wave into a lower-frequency one]. Low-pass filtering simply decreasing
the sharpness of an image while increasing its dull characteristics --
which is what I don't want.

That's a reasonable summary of what you don't want to do. What do you
think you might do instead?

#1 Decreases the rate at which objects in the video move without
decreasing the video's playback speed or eliminating originally-
rapidly-moving objects [such as the rapidly flapping wings]

Something has to give. If the flapping of the wings is slowed, so is the
motion of everything else.

#2 Decreases makes a still image less sharp by stretching everything
within the image without increasing the size of the image or
eliminating sharp portions of the original image

Huh?

Both #1 and #2 are visual-equivalents of decreasing the pitch of a
recorded audio signal without decreasing the audio's playback speed.

Says who? You're reasoning from false analogy again.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Radium[_4_]]

On Aug 19, 7:47 pm, Jerry Avins wrote:

Radium wrote:

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?

Describe a motion-free process of recording and playing back. Cutting
grooves on a disk or magnetizing a moving tape both involve motion.

The iPod is motion-free yet it's still able to record and playback.

Those Nintendo Entertainment System cartridges were able to playback
without any motion.

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"].

It's this simple: nobody has invented a way. I doubt than anyone ever
will. If you know how, communicate with me privately.

I don't know how but I guessing that it involves the analog equivalent
of Flash RAM [if re-writing is desired] or the analog equivalent of
Masked-ROM [if permanent storage is desired].

[Sjouke Burry]

Radium wrote:
On Aug 19, 7:47 pm, Jerry Avins wrote:

Radium wrote:

Other than the microphone [obviously], why does there need to be any
moving parts? If a digital audio device can play audio back without

Ah Radium trolling again i see!!!!

[Ron N.]

someone wrote:
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?

The basic physics of material objects leads to some
limitations. At some frequency, a given force can
no longer accelerate the mass of a given physical
transducer or recording substance by an amount
greater than does thermal noise (and other sources
of noise, such as friction, wear, dust, magnetic
particle size, film grain size, etc.)

[Bob Myers]

Radium 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?

What you are calling "bit resolution" is more commonly
referred to as bits/sample, or in video bits/color or per
component. It "enters into the equation" in all digital
encoding systems by setting the dynamic range that can
be encoded in that system, or, if you prefer, the "accuracy"
with which each sample represents the value of the original
signal at that point. The number of bits, along with the choice
of the maximum value which can be encoded (i.e., what level
"all ones" in the sample corresponds to) determines the value
represented by the least-significant bit.


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]

PCM has nothing to do with it.

Sample rate in audio = frame rate in video

No. There is no real analog, in audio, to the frame
rate in video, except to the extent that the frame rate
IS a sample rate in terms of capturing one complete
2-D image at that point in time - IF that is the way the
image capture device works (and not all work this way).
More typically, the "sample rate" in audio would be
thought of as corresponding to the pixel rate in video.

Channel in audio = pixel in video

Definitely not. A "pixel" in imaging is just what the
name says - it is a "picture element," meaning one
dimensionless point-sample of the original image, at
a specific location within the image plane and, in the
case of motion video, at a specific time. A pixel is
the best analog you will find to a single sample in
the case of digital audio.

Bit-resolution in audio = ? in video

Bits per sample is bits per sample, in either case.

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

A better way to say this is that you are concerned
with both temporal and spatial frequencies in the case of
motion video. (And, in the case of still images - as in
digital still photography - spatial frequencies only.)

II. Digital vs. Analog

Sample-rate is a digital entity.

Not really. While today most sampled systems are, in fact,
"digital" in nature (meaning that the information is encoded in
digital form), there is nothing in sampling theory which restricts
its applicability to that realm. Sampled analog systems are certainly
not very common today (unless you count certain forms of
modulation as "sampling," and in fact there are some very close
parallels there), but the theory remains the same no matter which
form of encoding is used. In any event, you must sample the
original signal at a rate equal to at least twice its bandwidth (actually,
very slightly higher, to avoid a particular degenerate case which
could occur at EXACTLY 2X the bandwidth) in order to preserve
the information in the original and avoid "aliasing."

Bob M.

[Jerry Avins]

Radium wrote:
On Aug 19, 7:47 pm, Jerry Avins wrote:

Radium wrote:

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?

Describe a motion-free process of recording and playing back. Cutting
grooves on a disk or magnetizing a moving tape both involve motion.

The iPod is motion-free yet it's still able to record and playback.

It does that digitally. Did you really not know that? Are you trolling
after all?

Those Nintendo Entertainment System cartridges were able to playback
without any motion.

It does that digitally. Did you really not know that? Are you trolling
after all?

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"].

It's this simple: nobody has invented a way. I doubt than anyone ever
will. If you know how, communicate with me privately.

I don't know how but I guessing that it involves the analog equivalent
of Flash RAM [if re-writing is desired] or the analog equivalent of
Masked-ROM [if permanent storage is desired].

What would you write into that "RAM"? There are no analog bits. The
analog equivalent of a masked ROM is a phonograph record. Think first.
Blather afterward, but show some sign of thought or you're not worth
bothering with.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Jerry Avins]

Bob Myers wrote:

... you must sample the
original signal at a rate equal to at least twice its bandwidth (actually,
very slightly higher, to avoid a particular degenerate case which
could occur at EXACTLY 2X the bandwidth) in order to preserve
the information in the original and avoid "aliasing."

Bob,

The degenerate case is just a limit. Signals close to the band edge take
a long time to be resolved. The time is of the order if 1/|f-F|, where F
is the frequency of the nearer band edge. Just as it takes in the order
of 100 seconds to resolve a frequency of .01 Hz, it takes the same time
to resolve a frequency of Fs/2 - .01 Hz. When f = Fs/2, it just takes
forever. The real works tends to be continuous.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Dave Platt]

In article . com,
Radium wrote:

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"].

The fact that it's an AC (inherently-varying) signal being recorded,
means that *something* has to move... if only some amount of
electrical charge. If the electrons don't move, the output can't vary
and all you have is a DC voltage.

And, in fact, this concept of moving electrical charges is the basis
for one type of analog signal storage and playback device which has no
moving (mechanical) parts... the CCD, or Charge Coupled Device. It
consists of a large number of charge storage devices (typically MOSFET
transistors with dielectrically-isolated gates) hooked up as a sort of
shift register or "bucket brigade". Each gate stores a charge which
is proportional to the input signal present at a given moment in time.
Several thousand times per second, a clock pulse causes each storage
cell to generate an output voltage proportional to the charge in its
storage gate, and then to "capture" onto its gate the signal being
presented by the previous gate in the chain.

In effect, the signal is propagated down the chain at a rate
proportional to the clock rate.

Why aren't these devices used more than they are? They're not very
efficient, and they're noisy. Every time the charge is copied from
one cell to the next, a bit of imprecision (noise) creeps in... so the
fidelity isn't great. And, because the device has to be able to hold
a very wide range of charges (since the charge is directly
proportional to the signal level) the storage gates have to be fairly
large.

The net result is that an audio CCD is capable of storing a
decent-quality signal for only a few tens or hundreds of milliseconds,
from input to output.

Another sort of a purely analog signal-storage device, with no moving
parts other than the electrons which convey the signal, is a simple
length of transmission line (with perhaps some amplifiers mid-way).
Put a signal in at one end, get the same signal back out the other end
some number of microseconds or milliseconds later.

Once again, they're not terribly efficient and are prone to be noisy.

For storage of large amounts of information, in a small space, with
high fidelity, using digital storage techniques is much more
efficient - largely because each storage cell must only store 2
different information states (0 and 1) rather than a large number of
possible levels.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[Radium[_4_]]

On Aug 19, 7:59 pm, Jerry Avins wrote:

Radium wrote:

2. Decreasing the spatial frequency of the images in the video-signal
without low-pass filtering the images or increasing their sizes. An
example of this would be making the sharp areas of an image look
duller without decreasing the "sharpness" setting [an example of low-
pass filtering] on the monitor or increasing the size of the image.
Normally, when the size of an image is decreased, its sharpness
increases [it's like compressing a lower-frequency sound wave into a
higher-frequency one]. Likewise, when the size of an image is
increased, it looks duller [like stretching a higher-frequency sound
wave into a lower-frequency one]. Low-pass filtering simply decreasing
the sharpness of an image while increasing its dull characteristics --
which is what I don't want.

That's a reasonable summary of what you don't want to do. What do you
think you might do instead?

The video-equivalent of changing the 'pitch' of audio recording
without changing the playback speed.

#1 Decreases the rate at which objects in the video move without
decreasing the video's playback speed or eliminating originally-
rapidly-moving objects [such as the rapidly flapping wings]

Something has to give. If the flapping of the wings is slowed, so is the
motion of everything else.

The motion of 'everything else' *is* slowed. However, the playback
speed remains constant.

Repetitive or cyclical motion (such as a ball bouncing, or a wagon
wheel rotating, or a bird-flapping its wings, or an exposed model of a
piston engine operating, or a flag waving in the wind) in the movie
are slowed without lengthening the clip.

#2 Decreases makes a still image less sharp by stretching everything
within the image without increasing the size of the image or
eliminating sharp portions of the original image

Huh?

Sorry that should read "makes a still image less sharp by stretching
everything within the image without increasing the size of the image
or eliminating sharp portions of the original image"

My bad.

Anyways, this is an original pictu
http://www-dse.doc.ic.ac.uk/~nd/surp...ormalimage.jpg

This is how the picture looks after low-pass filtering -- YUK!:

http://www-dse.doc.ic.ac.uk/~nd/surp...ort.lopass.jpg

I don't want low-pass filtering. I simply want all frequencies to be
downshifted similar to decreasing the pitch of audio without slowing
the playback speed. The analogy is lower the frequencies of all
components in the image w/out increasing the size of the image or
doing any low-pass filtering.

http://www-dse.doc.ic.ac.uk/~nd/surp...ab/report.html

Both #1 and #2 are visual-equivalents of decreasing the pitch of a
recorded audio signal without decreasing the audio's playback speed.

Says who? You're reasoning from false analogy again.

How is it false?

[Radium[_4_]]

On Aug 19, 8:34 pm, "Bob Myers" wrote:

Sampled analog systems are certainly
not very common today (unless you count certain forms of
modulation as "sampling," and in fact there are some very close
parallels there), but the theory remains the same no matter which
form of encoding is used. In any event, you must sample the
original signal at a rate equal to at least twice its bandwidth (actually,
very slightly higher, to avoid a particular degenerate case which
could occur at EXACTLY 2X the bandwidth) in order to preserve
the information in the original and avoid "aliasing."

Is the CCD [Charge Coupled Device] a "sampled analog system"?

[Jerry Avins]

Radium wrote:
On Aug 19, 7:59 pm, Jerry Avins wrote:

Radium wrote:

2. Decreasing the spatial frequency of the images in the video-signal
without low-pass filtering the images or increasing their sizes. An
example of this would be making the sharp areas of an image look
duller without decreasing the "sharpness" setting [an example of low-
pass filtering] on the monitor or increasing the size of the image.
Normally, when the size of an image is decreased, its sharpness
increases [it's like compressing a lower-frequency sound wave into a
higher-frequency one]. Likewise, when the size of an image is
increased, it looks duller [like stretching a higher-frequency sound
wave into a lower-frequency one]. Low-pass filtering simply decreasing
the sharpness of an image while increasing its dull characteristics --
which is what I don't want.

That's a reasonable summary of what you don't want to do. What do you
think you might do instead?

The video-equivalent of changing the 'pitch' of audio recording
without changing the playback speed.

That's just arm-waving words. Describe the result, not as an analogy,
but as a specification. If it turns out that you can't think critically
after all, I have no time for you.

#1 Decreases the rate at which objects in the video move without
decreasing the video's playback speed or eliminating originally-
rapidly-moving objects [such as the rapidly flapping wings]

Something has to give. If the flapping of the wings is slowed, so is the
motion of everything else.

The motion of 'everything else' *is* slowed. However, the playback
speed remains constant.

Explain how everything can slow town without increasing the time to
complete a motion. Sounds have duration and pitch. motion has no analog
of pitch in that sense. Describe the result you want, not "something
like" the result.

Repetitive or cyclical motion (such as a ball bouncing, or a wagon
wheel rotating, or a bird-flapping its wings, or an exposed model of a
piston engine operating, or a flag waving in the wind) in the movie
are slowed without lengthening the clip.

Tell me again how the crankshaft can take run one fifth speed without
using more time to make a turn.

#2 Decreases makes a still image less sharp by stretching everything
within the image without increasing the size of the image or
eliminating sharp portions of the original image

Huh?

Sorry that should read "makes a still image less sharp by stretching
everything within the image without increasing the size of the image
or eliminating sharp portions of the original image"

Tell me again how everything in an image can be stretched to double size
without making the image twice as big.

My bad.

You betcha.

Anyways, this is an original pictu
http://www-dse.doc.ic.ac.uk/~nd/surp...ormalimage.jpg

OK

This is how the picture looks after low-pass filtering -- YUK!:

http://www-dse.doc.ic.ac.uk/~nd/surp...ort.lopass.jpg

Fine detail (and noise) is gone.

I don't want low-pass filtering. I simply want all frequencies to be
downshifted similar to decreasing the pitch of audio without slowing
the playback speed. The analogy is lower the frequencies of all
components in the image w/out increasing the size of the image or
doing any low-pass filtering.

http://www-dse.doc.ic.ac.uk/~nd/surp...ab/report.html

Justify why you think that images and sounds are subject to the same
transformations.

Both #1 and #2 are visual-equivalents of decreasing the pitch of a
recorded audio signal without decreasing the audio's playback speed.

Says who? You're reasoning from false analogy again.

How is it false?

Images have no visual equivalent of pitch. Pitch is temporal. Images are
spatial.

Here's the deal: From now on, I'll only answer your technical questions
if you make a good effort to state all the assumptions behind it. I'll
work with you to get the assumptions out into the open, but I won't
answer a question until the assumptions are clear. Most of your
questions are so far into fantasy that the assumptions, once made
explicit, will likely seem contradictory even to you, and the question
will go away. E.g.: Don't ask me to explain the meaning of life without
our first establishing that life has a meaning.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Jerry Avins]

Radium wrote:
On Aug 19, 8:34 pm, "Bob Myers" wrote:

Sampled analog systems are certainly
not very common today (unless you count certain forms of
modulation as "sampling," and in fact there are some very close
parallels there), but the theory remains the same no matter which
form of encoding is used. In any event, you must sample the
original signal at a rate equal to at least twice its bandwidth (actually,
very slightly higher, to avoid a particular degenerate case which
could occur at EXACTLY 2X the bandwidth) in order to preserve
the information in the original and avoid "aliasing."

Is the CCD [Charge Coupled Device] a "sampled analog system"?

Yes.

Jerry
--
A good newspaper is one that prints only what you want others to know.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Radium[_4_]]

On Aug 19, 8:54 pm, (Dave Platt) wrote:

The fact that it's an AC (inherently-varying) signal being recorded,
means that *something* has to move... if only some amount of
electrical charge. If the electrons don't move, the output can't vary
and all you have is a DC voltage.

By "moving parts" I mean mechanical parts. Not electrons.

And, in fact, this concept of moving electrical charges is the basis
for one type of analog signal storage and playback device which has no
moving (mechanical) parts... the CCD, or Charge Coupled Device. It
consists of a large number of charge storage devices (typically MOSFET
transistors with dielectrically-isolated gates) hooked up as a sort of
shift register or "bucket brigade". Each gate stores a charge which
is proportional to the input signal present at a given moment in time.
Several thousand times per second, a clock pulse causes each storage
cell to generate an output voltage proportional to the charge in its
storage gate, and then to "capture" onto its gate the signal being
presented by the previous gate in the chain.

In effect, the signal is propagated down the chain at a rate
proportional to the clock rate.

Is CCD a form of analog non-volatile RAM?

Why aren't these devices used more than they are? They're not very
efficient, and they're noisy. Every time the charge is copied from
one cell to the next, a bit of imprecision (noise) creeps in... so the
fidelity isn't great. And, because the device has to be able to hold
a very wide range of charges (since the charge is directly
proportional to the signal level) the storage gates have to be fairly
large.

I wonder how a PC would perform if it used CCDs in place of digital
storage devices. Lots of errors.

The net result is that an audio CCD is capable of storing a
decent-quality signal for only a few tens or hundreds of milliseconds,
from input to output.

What is the highest frequency an audio CCD can input and output? My
guess is 0.5x the clock rate.

Another sort of a purely analog signal-storage device, with no moving
parts other than the electrons which convey the signal, is a simple
length of transmission line (with perhaps some amplifiers mid-way).

Where is the "storage" in this device?

Put a signal in at one end, get the same signal back out the other end
some number of microseconds or milliseconds later.

Where is the signal being stored?

[Jerry Avins]

Dave Platt wrote:
In article . com,
Radium wrote:

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"].

The fact that it's an AC (inherently-varying) signal being recorded,
means that *something* has to move... if only some amount of
electrical charge. If the electrons don't move, the output can't vary
and all you have is a DC voltage.

And, in fact, this concept of moving electrical charges is the basis
for one type of analog signal storage and playback device which has no
moving (mechanical) parts... the CCD, or Charge Coupled Device. It
consists of a large number of charge storage devices (typically MOSFET
transistors with dielectrically-isolated gates) hooked up as a sort of
shift register or "bucket brigade". Each gate stores a charge which
is proportional to the input signal present at a given moment in time.
Several thousand times per second, a clock pulse causes each storage
cell to generate an output voltage proportional to the charge in its
storage gate, and then to "capture" onto its gate the signal being
presented by the previous gate in the chain.

In effect, the signal is propagated down the chain at a rate
proportional to the clock rate.

Why aren't these devices used more than they are? They're not very
efficient, and they're noisy. Every time the charge is copied from
one cell to the next, a bit of imprecision (noise) creeps in... so the
fidelity isn't great. And, because the device has to be able to hold
a very wide range of charges (since the charge is directly
proportional to the signal level) the storage gates have to be fairly
large.

The net result is that an audio CCD is capable of storing a
decent-quality signal for only a few tens or hundreds of milliseconds,
from input to output.

Another sort of a purely analog signal-storage device, with no moving
parts other than the electrons which convey the signal, is a simple
length of transmission line (with perhaps some amplifiers mid-way).
Put a signal in at one end, get the same signal back out the other end
some number of microseconds or milliseconds later.

Once again, they're not terribly efficient and are prone to be noisy.

For storage of large amounts of information, in a small space, with
high fidelity, using digital storage techniques is much more
efficient - largely because each storage cell must only store 2
different information states (0 and 1) rather than a large number of
possible levels.

Come on, Dave, a CCD is a digital device, subject to aliasing. The
charges represent the signal at a particular instant of its average over
a particular interval. (My CCD digital camera can take time exposures.)
A CCD's content may not be quantized in amount, but it is quantized in
time. In a camera, where the charges pertain to individual pixels, the
result is also quantized in space.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Dave Platt]

Come on, Dave, a CCD is a digital device, subject to aliasing. The
charges represent the signal at a particular instant of its average over
a particular interval. (My CCD digital camera can take time exposures.)
A CCD's content may not be quantized in amount, but it is quantized in
time. In a camera, where the charges pertain to individual pixels, the
result is also quantized in space.

"Digital" and "subject to aliasing" are two different things.

As I believe the term "digital" is usually meant, it implies a
two-state (on/off) storage representation. It's not just that the
signal amplitude is quantized, but that the quantization uses a
power-of-two representation and storage system of some sort.

In that sense, an audio CCD uses a digital clocking structure to move
the charge along, but uses a non-digital system for representing the
signal level (a linear number of electrons). Yes, it's quantized in
time, and the electron charges themselves are quantized... but I don't
think that either of these qualifies it as "digital".

"Analog" is a very fuzzy and imprecise term, and I think that a CCD
can reasonably be called an analog system.

Even audio cassette tape is quantized in both time and amplitude, at
the level of the individual magnetic domains in the oxide or metal
particles.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[Radium[_4_]]

On Aug 19, 10:08 pm, Jerry Avins wrote:

Radium wrote:

The video-equivalent of changing the 'pitch' of audio recording
without changing the playback speed.

That's just arm-waving words. Describe the result, not as an analogy,
but as a specification. If it turns out that you can't think critically
after all, I have no time for you.

The purpose of this visual "pitch-shifting" is like a way to record/
playback/transmit/receive/store supreme-quality video while using the
least bandwidth and storage space necessary when low-pass filtering is
not an option.

Using this video frequency-shifting, a high-quality video can be
stored in an extremely slow moving video-cassette with limited amount
of tape. Due to the video-tape's extremely slow speed the temporal and
spatial frequencies of the incoming video signals must be downshifted
in order to be encoded at such slow speeds. Due to the limited length
of film in the cassette, the movie must not be made longer than what
it originally is. Due to other inadequacies in the film, the spatial-
frequency must also be decreased, but the image size must not
increase.

The motion of 'everything else' *is* slowed. However, the playback
speed remains constant.

Explain how everything can slow town without increasing the time to
complete a motion. Sounds have duration and pitch. motion has no analog
of pitch in that sense. Describe the result you want, not "something
like" the result.

A 2 hour high-quality movie should be able to be stored in device with
limited high-frequency response and limited amount of storage space.
There should be absolutely no aliasing -- temporal or spatial - but at
the same time, the length of the movie should not be increased, sizes
of objects in images should not increase, image size should not
increase and no low-pass filtering should be used.

Repetitive or cyclical motion (such as a ball bouncing, or a wagon
wheel rotating, or a bird-flapping its wings, or an exposed model of a
piston engine operating, or a flag waving in the wind) in the movie
are slowed without lengthening the clip.

Tell me again how the crankshaft can take run one fifth speed without
using more time to make a turn.

I wish I knew. This 'pitch-shifting' is a lot more confusing than I
thought. Yet I still find it so interesting. Sorry.

Sorry that should read "makes a still image less sharp by stretching
everything within the image without increasing the size of the image
or eliminating sharp portions of the original image"

Tell me again how everything in an image can be stretched to double size
without making the image twice as big.

Nothing in the image has its size increased. They are simply smoothed
out.

This is similar to a graph of digital audio in Adobe Audition. You
decrease the pitch of the audio in the file by half [without changing
the tempo] and the waves in the graph will appear twice as long but
without increasing the horizontal length of the graph.

I don't want low-pass filtering. I simply want all frequencies to be
downshifted similar to decreasing the pitch of audio without slowing
the playback speed. The analogy is lower the frequencies of all
components in the image w/out increasing the size of the image or
doing any low-pass filtering.

http://www-dse.doc.ic.ac.uk/~nd/surp...ab/report.html

Justify why you think that images and sounds are subject to the same
transformations.

The less sample rate you have in digital audio, the lower the
frequency of the audio must be in order to prevent aliasing. There
isn't enough bandwidth to include the higher-pitches.

Similarly an imaging device with insufficient spatial bandwidth will
result in image distortion if excessively fine detail is put into the
camera.

Hence, if you want to get decent imagery in a low-bandwidth imaging
device, your best bet is to decrease the spatial frequency because
transferring it into the imaging device.

Just like if you have an 11.025-KHz-sample-rate digital audio device,
you need to make sure the pitch of the audio you are inputting into
the device does not exceed 5.5125 KHz.

How is it false?

Images have no visual equivalent of pitch. Pitch is temporal. Images are
spatial.

Spatial frequency is how fine or dull an image is. Pitch is determined
by audio frequency. I am using the spatial frequency as an analogy.

[Jerry Avins]

Dave Platt wrote:
Come on, Dave, a CCD is a digital device, subject to aliasing. The
charges represent the signal at a particular instant of its average over
a particular interval. (My CCD digital camera can take time exposures.)
A CCD's content may not be quantized in amount, but it is quantized in
time. In a camera, where the charges pertain to individual pixels, the
result is also quantized in space.

"Digital" and "subject to aliasing" are two different things.

As I believe the term "digital" is usually meant, it implies a
two-state (on/off) storage representation. It's not just that the
signal amplitude is quantized, but that the quantization uses a
power-of-two representation and storage system of some sort.

I can buy that, but it's not how I would have used the term. I call a
two-state representation "binary". A storage system that is clocked is
subject to most of the restrictions and permits most of the useful
techniques of digital signal processing. Early transversal filters used
op-amps, with the coefficients being set by the resistor values.

In that sense, an audio CCD uses a digital clocking structure to move
the charge along, but uses a non-digital system for representing the
signal level (a linear number of electrons). Yes, it's quantized in
time, and the electron charges themselves are quantized... but I don't
think that either of these qualifies it as "digital".

I agree to use your term for the sake of this discussion.

"Analog" is a very fuzzy and imprecise term, and I think that a CCD
can reasonably be called an analog system.

Yet I'd lay a bet that you call the pictures made by means of a CCD
image sensor "digital".

Even audio cassette tape is quantized in both time and amplitude, at
the level of the individual magnetic domains in the oxide or metal
particles.

Oh, sure. In that case, the crystal radio that I built in the 40s was
digital too. The electrons came down the antenna one at a time even if
closely spaced. We need to draw a line somewhere, and I don't like the
idea of calling a flashlight a digital photonic device.

There are in principle purely analog storage devices. A loop of analog
delay line with a repeater in it qualifies. A memory based on that
principle was used to store digital signals in an early computer, even
though the device itself is analog. It used an acoustic delay in a
column of mercury.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Don Pearce]

On Sun, 19 Aug 2007 23:26:16 -0700, (Dave Platt)
wrote:

"Digital" and "subject to aliasing" are two different things.

As I believe the term "digital" is usually meant, it implies a
two-state (on/off) storage representation. It's not just that the
signal amplitude is quantized, but that the quantization uses a
power-of-two representation and storage system of some sort.

My reading of the possible systems goes like this.

analogue - a continuous representation of the original signal
sampled - a representation of the signal at discrete time points
quantized - a sampled signal, but with the possible levels constrained
to a limited set of values
digital - a quantized signal, with the individual levels represented
by numbers

Aliasing is going to happen as soon as you move beyond the first line
of that list.

d

--
Pearce Consulting
http://www.pearce.uk.com

[Jerry Avins]

Radium wrote:
On Aug 19, 10:08 pm, Jerry Avins wrote:

Radium wrote:

The video-equivalent of changing the 'pitch' of audio recording
without changing the playback speed.

That's just arm-waving words. Describe the result, not as an analogy,
but as a specification. If it turns out that you can't think critically
after all, I have no time for you.

The purpose of this visual "pitch-shifting" is like a way to record/
playback/transmit/receive/store supreme-quality video while using the
least bandwidth and storage space necessary when low-pass filtering is
not an option.

If you have a purpose in mind, you must have a pretty good idea of what
it does. If you can make that clear, we might have something to discuss.

Using this video frequency-shifting, a high-quality video can be
stored in an extremely slow moving video-cassette with limited amount
of tape. Due to the video-tape's extremely slow speed the temporal and
spatial frequencies of the incoming video signals must be downshifted
in order to be encoded at such slow speeds. Due to the limited length
of film in the cassette, the movie must not be made longer than what
it originally is. Due to other inadequacies in the film, the spatial-
frequency must also be decreased, but the image size must not
increase.

More arm waving. Tell me how you think it might be accomplished. (Hint:
it sounds like nonsense to me. One of those revelatory dreams that seem
so clear until I wake up.

The motion of 'everything else' *is* slowed. However, the playback
speed remains constant.

Explain how everything can slow town without increasing the time to
complete a motion. Sounds have duration and pitch. motion has no analog
of pitch in that sense. Describe the result you want, not "something
like" the result.

A 2 hour high-quality movie should be able to be stored in device with
limited high-frequency response and limited amount of storage space.
There should be absolutely no aliasing -- temporal or spatial - but at
the same time, the length of the movie should not be increased, sizes
of objects in images should not increase, image size should not
increase and no low-pass filtering should be used.

"Should" is an interesting word. It can prescribe and it can express an
expectation or desire. In this case, your desire is contrary to my
expectation.

Repetitive or cyclical motion (such as a ball bouncing, or a wagon
wheel rotating, or a bird-flapping its wings, or an exposed model of a
piston engine operating, or a flag waving in the wind) in the movie
are slowed without lengthening the clip.

Tell me again how the crankshaft can take run one fifth speed without
using more time to make a turn.

I wish I knew. This 'pitch-shifting' is a lot more confusing than I
thought. Yet I still find it so interesting. Sorry.

Don't be sorry. If you work out the details, I'll help you to see the
inherent contradictions they impose, but I won't argue with you about it.

Sorry that should read "makes a still image less sharp by stretching
everything within the image without increasing the size of the image
or eliminating sharp portions of the original image"

Tell me again how everything in an image can be stretched to double size
without making the image twice as big.

Nothing in the image has its size increased. They are simply smoothed
out.

This is similar to a graph of digital audio in Adobe Audition. You
decrease the pitch of the audio in the file by half [without changing
the tempo] and the waves in the graph will appear twice as long but
without increasing the horizontal length of the graph.

I don't want low-pass filtering. I simply want all frequencies to be
downshifted similar to decreasing the pitch of audio without slowing
the playback speed. The analogy is lower the frequencies of all
components in the image w/out increasing the size of the image or
doing any low-pass filtering.

http://www-dse.doc.ic.ac.uk/~nd/surp...ab/report.html

Justify why you think that images and sounds are subject to the same
transformations.

The less sample rate you have in digital audio, the lower the
frequency of the audio must be in order to prevent aliasing. There
isn't enough bandwidth to include the higher-pitches.

Similarly an imaging device with insufficient spatial bandwidth will
result in image distortion if excessively fine detail is put into the
camera.

That's true only if you mean spatial aliasing. Otherwise, you're using
"distortion" in a non-standard way.

Hence, if you want to get decent imagery in a low-bandwidth imaging
device, your best bet is to decrease the spatial frequency because
transferring it into the imaging device.

More nonsense. Think about it and tell me why.

Just like if you have an 11.025-KHz-sample-rate digital audio device,
you need to make sure the pitch of the audio you are inputting into
the device does not exceed 5.5125 KHz.

How does that make for "decent imagery? It amounts to a low-pass filter,
about which you remarked, "ugh".

How is it false?

Images have no visual equivalent of pitch. Pitch is temporal. Images are
spatial.

Spatial frequency is how fine or dull an image is. Pitch is determined
by audio frequency. I am using the spatial frequency as an analogy.

Stop with analogies. Say what you mean.

Here's the picture of you that I have in my head: You were a precocious
kid, and impressed those around by asking questions that were further
out than what most kids asked. (Reading a lot leads one to do that.) The
adults around you patted you on the head and praised you for digging
into subjects they knew little or nothing about.* They knew so little
about it that they didn't understand much of what you talked about, and
so couldn't set you back on the rails when you wandered away from
reality. No matter, the praise kept coming anyway, and you learned that
if you imagined something, it was golden. It wasn't really, but those
around you taught you to believe that it was. Now you find yourself
going on about your imaginings with people who _do_ understand the
subject you fantasize about and their reaction hurts, but you're finding
it very hard to get out of bull**** mode and ask basic questions. It
hasn't sunk in yet that you don't even have basic answers because you
still believe that the fantasies you construct are real. I hope you get
over that. In the meanwhile, I feel sorry for you.

Jerry
___________________________________
* From Gilbert and Sullivan's /Patience/: "If this young man expresses
himself in terms too deep for me/ Why what a very singularly deep young
man/ This deep young man must be" Your type has been mocked a long time.
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Martin Heffels]

On Sun, 19 Aug 2007 18:14:58 -0700, Radium wrote:

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?

Because if it could, there would be no need to invent digital which has the
advantage of non-moving parts....................

-m-
--
Official website "Jonah's Quid" http://www.jonahsquids.co.uk

[Martin Heffels]

On Sun, 19 Aug 2007 20:54:06 -0700, (Dave Platt) wrote:

Another sort of a purely analog signal-storage device, with no moving
parts other than the electrons which convey the signal, is a simple
length of transmission line

Here is a better one: transmit the analogue system to the sun, and you have
16 minute, once-of storage. If you want to save your recording for a longer
time, you can pick more planets and stars, further away, and bounce your
radiosignal off them. It is obviously not random-access, but it is very
analogue.

-m-
--
Official website "Jonah's Quid" http://www.jonahsquids.co.uk

[Jerry Avins]

Don Pearce wrote:
On Sun, 19 Aug 2007 23:26:16 -0700, (Dave Platt)
wrote:

"Digital" and "subject to aliasing" are two different things.

As I believe the term "digital" is usually meant, it implies a
two-state (on/off) storage representation. It's not just that the
signal amplitude is quantized, but that the quantization uses a
power-of-two representation and storage system of some sort.

My reading of the possible systems goes like this.

analogue - a continuous representation of the original signal
sampled - a representation of the signal at discrete time points
quantized - a sampled signal, but with the possible levels constrained
to a limited set of values
digital - a quantized signal, with the individual levels represented
by numbers

Aliasing is going to happen as soon as you move beyond the first line
of that list.

I like your categories. It is possible in concept to have a signal that
is quantized in magnitude and continuous in time, but (unless we resort
to counting electrons) I don't think it's possible in practice.

jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Don Pearce]

On Mon, 20 Aug 2007 03:51:54 -0400, Jerry Avins wrote:

Don Pearce wrote:
On Sun, 19 Aug 2007 23:26:16 -0700, (Dave Platt)
wrote:

"Digital" and "subject to aliasing" are two different things.

As I believe the term "digital" is usually meant, it implies a
two-state (on/off) storage representation. It's not just that the
signal amplitude is quantized, but that the quantization uses a
power-of-two representation and storage system of some sort.

My reading of the possible systems goes like this.

analogue - a continuous representation of the original signal
sampled - a representation of the signal at discrete time points
quantized - a sampled signal, but with the possible levels constrained
to a limited set of values
digital - a quantized signal, with the individual levels represented
by numbers

Aliasing is going to happen as soon as you move beyond the first line
of that list.

I like your categories. It is possible in concept to have a signal that
is quantized in magnitude and continuous in time, but (unless we resort
to counting electrons) I don't think it's possible in practice.

Yes, I was thinking about that possibility while I was typing, but
since I've never come across such a system I decided it would
complicate things unnecessarily to include it.

d

--
Pearce Consulting
http://www.pearce.uk.com

[Jerry Avins]

Martin Heffels wrote:
On Sun, 19 Aug 2007 18:14:58 -0700, Radium wrote:

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?

Because if it could, there would be no need to invent digital which has the
advantage of non-moving parts....................

Actually, I did invent something along those lines, but I was foolish
enough yo leave the plans in my (not yet perfected) time machine, and
they disappeared.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

[Martin Heffels]

On Mon, 20 Aug 2007 04:16:44 -0400, Jerry Avins wrote:

Actually, I did invent something along those lines, but I was foolish
enough yo leave the plans in my (not yet perfected) time machine, and
they disappeared.

Shame on you! Radium will be very disappointed now.

-m-
--
Official website "Jonah's Quid" http://www.jonahsquids.co.uk

[Richard Dobson]

Radium wrote:
On Aug 19, 6:08 pm, Jerry Avins wrote:


Radium wrote:


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.


I am talking about:

1. Decreasing the temporal frequency of the video signal without low-
pass filtering or decreasing the playback speed - an example of which
would be decreasing the rate at which a bird [in the movie] flaps its
wings. Hummingbirds flap their wings too fast for the human eye to
see. So the flap-rate of the wings could be decreased until the
flapping is visible to the human eye - without decreasing the playback
speed of the video. This decrease in flap-rate without slowing
playback is visually-analogous to decreasing the pitch of a recorded
sound without decreasing the playback speed. In this case, low-pass
filter would involve attenuating rapidly-changing images while
amplifying slowly-changing images -- I don't want this.


I confess I am jumping into a thread having just discovered it.

There are some mixed metaphors here. There is a video equivalent to
audio pitch shifting. think of the latter represetned in the frequency
domain (spectrum) - the peak correspindsing to the source partial moves
down (or up). the video equivalent is colour cycling or shifting. But
most simply, reds would be shifted to orange, green shifted to blue,
violet to ultra-violet (and hence llost to view). An alternatyive
stratgy is colour rotation using the artists colour wheel, where,
ideally, diametrically opposite colours are complementary. There is no
equivalent that I know of to colour complemenariness in audio.

I ~think~ I get what Radium wants - he wants to be able to modify a
recorded scene the way one can modify a CGI virtual scene, e.g. by
setting a slower wing flapping rate while leaving other parts of the
scene unchanged. As far as I know, computer vision and scene analysis is
nowhere near being able to do this. The only audio parallel I can think
of is wanting to pitch shift just one instrument in a polyphonic
texture, leaving other voices unchanged. With luck, some implementations
of Blind Source Separation can sometimes do this (they need the mixed
sounds to be very distinct - I have seen one example demonstrated at
DaFX); ths difficulties with video I would expect to be order of
magnitude greater.


Richard Dobson

[Floyd L. Davidson]

Jerry Avins wrote:
Dave Platt wrote:
In article . com,
Radium wrote:

I'm curious to why there are no purely-analog devices which can
record, store, and playback electric audio signals [AC currents at
....

The net result is that an audio CCD is capable of
storing a
decent-quality signal for only a few tens or hundreds of milliseconds,
from input to output.
Another sort of a purely analog signal-storage device,
with no moving
parts other than the electrons which convey the signal, is a simple
length of transmission line (with perhaps some amplifiers mid-way).

....

Come on, Dave, a CCD is a digital device, subject to
aliasing.

CCDs are analog devices, with an analog voltage output.

The fact that they are commonly used as the sensor in
digital cameras results in the output of a CCD virtually
always going directly (well, after a bit of signal
processing for things such as white balance, ISO gain,
etc.) to an analog-to-digital converter that digitizes
the analog signal.

The charges represent the signal at a
particular instant of its average over a particular
interval. (My CCD digital camera can take time
exposures.) A CCD's content may not be quantized in
amount, but it is quantized in time. In a camera, where
the charges pertain to individual pixels, the result is
also quantized in space.

But none of that quantization changes the fact that the
device itself has an analog output.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

[glen herrmannsfeldt]

Dave Platt wrote:

(snip)

As I believe the term "digital" is usually meant, it implies a
two-state (on/off) storage representation. It's not just that the
signal amplitude is quantized, but that the quantization uses a
power-of-two representation and storage system of some sort.

It means discrete states, but the base does not have to be two.

Many of the early computers were decimal based, and not
necessarily BCD.

The Fortran standard still allows for any base greater
than one to be used for representing values.

-- glen