On 6/4/06, <b class="gmail_sendername">Mathieu Bouchard</b> <<a href="mailto:matju@artengine.ca">matju@artengine.ca</a>> wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Sun, 4 Jun 2006, chris clepper wrote:<br><br>> Can you go into more detail about the revisions to block~? My rough<br>> calculations put a 720x480 YCbCr image at about 64 times the data of a<br>> single 96khz audio signal. RGBA is double that.
<br><br>How do you compute that?<br><br>DV-NTSC is 720 px * 480 px * 30 Hz * 2 samples/px^2 = 20736000 samples/s<br>DV-PAL is 720 px * 576 px * 25 Hz * 2 samples/px^2 = 20736000 samples/s<br>96 kHz mono is 96000 Hz * 1 samples = 96000 samples/s
<br><br>and 20736000/96000 = exactly 216 = 6*6*6 but closest powers of 2 are 2^7 =<br>128 and 2^8 = 256. (comparing with stereo sound doesn't change the<br>relative closeness of powers of two)</blockquote><div><br>I forgot to make the video signal 4 bytes per channel in my calculation. If you compare the 4 byte audio to single byte per channel video then it is 54 times the data. 64 is the next power of two.
<br><br>Your numbers are the right ones to use.<br></div><br></div><br>