<div dir="ltr"><br><br><div class="gmail_quote">On Wed, Oct 15, 2008 at 2:40 AM, Ian Hickson <span dir="ltr"><ian@hixie.ch></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">On Tue, 14 Oct 2008, Sander van Zoest wrote:<br>
><br>
> I just recently started looking at HTML5 and noticed the video tag. Neat<br>
> addition. I also noticed that it as an attribute named 'pixelratio',<br>
> however, as you know this is never an integer, but rather is the result<br>
> of a fraction (i.e. ratio). As for proper playback of video frames, it<br>
> is important to understand exact float and therefore I would suggest<br>
> either expressing it as a ratio of two 32-bit integers separated by a<br>
> colon (or slash) or use two different attributes. This avoids<br>
> unintentional rounding.<br>
><br>
> Something roughly along the lines of:<br>
><br>
</div>> <source pixelratio="10:11"> <!-- 525 composite NTSC --><br>
> <source pixelratio="59:54"> <!-- 625 composite PAL --><br>
> <source pixelratio="1018:1062"> <!-- 1920x1035 HDTV SMPTE RP 187-1995 --><br>
<br>
Currently pixelratio is a floating point number, as in:<br>
<br>
<source pixelratio="0.909090909"> <!-- 525 composite NTSC --><br>
<source pixelratio="1.09259259"> <!-- 625 composite PAL --><br>
<source pixelratio="0.958568738"> <!-- 1920x1035 HDTV SMPTE RP 187-1995 --><br>
<br>
Is that not enough?<br>
<br>
This isn't expected to be used often. It's really only provided to allow<br>
for simple override of the actual value in the video file, for when the<br>
video file is known to be wrong. I am very reluctant to make up a whole<br>
new microsyntax and corresponding parser algorithm, along with all the<br>
tests, etc, to handle this one case.<font color="#888888"></font></blockquote><div><br>I hate to say it, but if it was enough, I wouldn't be commenting here. It simply isn't accurate<br>enough to store it as a float. Every respected container stores the ratio as X x Y.<br>
See the PASP atom for example. <br></div></div><br>-- Sander<br>
</div>