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.
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