Using Prebid's price granularity high - header

Question

We have our Price Granularity for Prebid set to high. However, since it's capped at $20, if we get a bid for $30 or $40 we're unable to accept it.
How can we stick with Price Granularity high with Prebid, but in instances we have a bid north of $20, automatically round down to $20 so that we can accept the bid.
Thank you..

Answer 1

According to Prebid documentation is should already be rounded down, but you can explicitly control it by adding the following code.
Assuming you're using the standard Prebid targeting keys
pbjs.bidderSettings.standard = {
adserverTargeting: [{
key: 'hb_bidder',
val: function val(bidResponse) {
return bidResponse.bidderCode;
}
}, {
key: 'hb_adid',
val: function val(bidResponse) {
return bidResponse.adId;
}
}, {
key: 'hb_pb',
val: function val(bidResponse) {
var cpm = bidResponse.cpm;
if (cpm > 20.00) {
return 20.00;
}
return (Math.floor(cpm * 100) / 100).toFixed(2);
}
}]
};
Add this after pbjs.addAdUnits( ad_units )

Answer 2

You’ll want to use the custom setting instead of using high to get what you want
See an example here: http://prebid.org/dev-docs/publisher-api-reference.html#customCPMObject
For the JSON youll want to redefine the same granularity settings for high in that JSON object and then add upon it to get additional granularity > $20.
Pro tips:
if you do not define values between $0-$x.xx that can act as a floor if you never want bids lower than x going to DFP
DFP caps the number of line items in an order at 450, so you may need an additional order(s) for your new granularity
always overlap the settings. Eg. Bucket 1 = $0-$3.00. Bucket 2 should start at $3.00-x (if you dont, a $3.009 bid wont be passed in to DFP