Device resolution and pixel density

[Sam Tingleff]

Today seems to be the day, so I'll throw this out as well.

We're currently sending these three fields as extensions in the device object.

h is height of the screen in pixels (int)
w is width of the screen in pixels (int)
pixelratio is a ratio of physical pixels to device independent pixels
(dips) on the device, e.g., 1 for non-retina iOS, 2 for Retina Display
(float)

It seems to me that they would belong in a new child object of device:

{
...
"device":{
...
"res":{
"h": 1440,
"w": 900,
"pixelratio": 1
}
}
}

[AntonR]

Sam, how are DSPs using this data?

Thanks,

Anton

[Sam Tingleff]

For one thing resolution is the only way to differentiate an ipad 2 from a retina ipad (on same osv) for targeting.

Pixel density is typically used to serve different creatives for the same ad size. A 300x250 serving on an ipad 2 would see a different image from a retina ipad, or a highly pixel dense android device.

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[Jim Butler]

We recently added a pixel density extension, which I was going to propose for 2.3 for the same reasons.  We also added a device hardware version, which I would also like to propose.  We’ve been getting requests for both of these from DSPs.

 

:JB

[Anton Roslov]

Sam, if you already know the device is ipad 2, then why not you use device.model and device.make for the same purpose? 

Re pixelratio: seems like we are talking HTML ads, so don't DSPs use CSS (webkit-min-device-pixel-ratio) for this? Seems like CSS approach removes the need to duplicate creatives in the system and one can bid with the same response for many devices. Although in native you probably can't avoid using the pixelratio in bid, as there is no CSS...

[Sam Tingleff]

The only reason we (SSP) might know that a device is an ipad 2 is via resolution and pixel density (or native code on the device). The user agent provides no such information. While we could modify device.make or device.model, why not instead pass on the raw information used to make that determination?

[LP]

Could you please clarify for me, what units (physical or device-independent pixels) should be used for device.w and device.h params?

[Jim Butler]

V2.3 will include the following related to the device:

• Attribute device.h (optional integer) as the physical height of the screen in pixels.
• Attribute device.w (optional integer) as the physical width of the screen in pixels.
• Attribute device.pxratio (optional float) as the ratio of physical pixels to device independent pixels.
• Attribute device.ppi (optional integer) as the pixels per linear inch.

 

:JB