[whatwg] video tag: pixel aspect ratio

Sander van Zoest sander at vanzoest.com
Tue Oct 14 10:13:32 PDT 2008

On Tue, Oct 14, 2008 at 9:39 AM, Sander van Zoest <sander at vanzoest.com>wrote:

> Hi,
> I just recently started looking at HTML5 and noticed the video tag. Neat
> addition.
> I also noticed that it as an attribute named 'pixelratio', however, as you
> know this
> is never an integer, but rather is the result of a fraction (i.e. ratio).
> As for proper
> playback of video frames, it is important to understand exact float and
> therefore
> I would suggest either expressing it as a ratio of two 32-bit integers
> separated by a colon (or slash) or use two
> different attributes. This avoids unintentional rounding.
> Something roughly along the lines of:
> <video pixelratio="10:11"> <!-- 525 composite NTSC -->
> <video pixelratio="59:54"> <!-- 625 composite PAL -->
> <video pixelratio="1018:1062"> <!-- 1920x1035 HDTV SMPTE RP 187-1995 -->
> <video parhSpacing="10" parvSpacing=11">
> Container formats tend to store this information in a ratio like this and
> not in a float.

Please excuse me for referencing the video tag as, after further reading, it
is apparent that the pixelratio attribute is applied to the source tag.
Regardless, I believe the same points apply, so therefore please mentally
/video/source/ . Thank you and sorry for the confusion and stress I may

-- Sander
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