[PD-dev] call for discussion: native video for Pd

[Mathieu Bouchard]

On Sun, 4 Jun 2006, chris clepper wrote:

> Can you go into more detail about the revisions to block~?  My rough 
> calculations put a 720x480 YCbCr image at about 64 times the data of a 
> single 96khz audio signal.  RGBA is double that.

How do you compute that?

DV-NTSC is 720 px * 480 px * 30 Hz * 2 samples/px^2 = 20736000 samples/s
DV-PAL  is 720 px * 576 px * 25 Hz * 2 samples/px^2 = 20736000 samples/s
96 kHz mono is            96000 Hz * 1 samples      =    96000 samples/s

and 20736000/96000 = exactly 216 = 6*6*6 but closest powers of 2 are 2^7 = 
128 and 2^8 = 256. (comparing with stereo sound doesn't change the 
relative closeness of powers of two)

add to this that I want to use the framesizes I want, the screen aspect 
ratios I want, and the framerates I want, and I think that pretty much 
everyone wants that.

PS: I don't understand what you say: if you really want to compare one 
single frame of video with sound, you have to say the duration of the 
sound that you compare it with. If the duration is dictated by standard 
video frame duration standards, you'll get to the same figures that I have 
gotten to above.

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| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada