Re: [Workshop-2011] V4L2 API ambiguities: workshop presentation

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 08/17/2012 02:57 PM, Laurent Pinchart wrote:

<Snip>

>> Regarding ENUM_FRAMESIZES: it makes sense to add an aspect ratio here for
>> use with sensors. But for video receivers ENUM_FRAMESIZES isn't applicable.
>
> Do we have sensors with non-square pixels ?

Short answer: not that I know of.

Long answer: that depends on the optics (so the sensor pixels may be square,
but the optics could make them non-square from a proper mapping to a real world
picture pov).

As I've done too much with weird old webcams I actually now webcams which do
this, the vicam cameras to be precise. The 3 com HomeConnect (04c1:009) has
a sensor with a native resolution of 512x244, yeah widescreen baby!

But it stems from an area where widescreen was unheard of in computer graphics,
so it actually has optics which force that cool widescreen resolution back into
a 4x3 field of view. So for a proper square pixels image form that camera its
image needs to be scaled from 512x244 to 512x384 (*). But with that one exception
proving the rule (Dutch expression), I think all sensors have square pixels.

Regards,

Hans

*) Really? Yes really!