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