Hi, On Fri, Sep 23, 2022 at 11:05:48AM +0200, Thomas Zimmermann wrote: > > + /* 63.556us * 13.5MHz = 858 pixels */ > > I kind of get what the comment wants to tell me, but the units don't add up. I'm not sure how it doesn't add up? We have a frequency in Hz (equivalent to s^-1) and a duration in s, so the result ends up with no dimension, which is to be expected for a number of periods? If you're talking about the comment itself, then NTSC mandates that a line is 63.556us long. If we're using a pixel clock at 13.5 MHz, it means that the period (== pixel) is ~74ns, so we get 63556 / 74 = 858 pixels / line. > I think you want to end up with 858 pixels/line = > > 13,5 pixels/second / (60/2I frame/second * 525 lines/frame) > > I: interlaced > > Maybe just remove the short comments and document that in a more meaningful > place. I guess this is where it's meaningful, we really want to hit that target. BT601 also mandates it. Maxime
Attachment:
signature.asc
Description: PGP signature
