It's definitely not the PK-18 the Army Chief General Bajwa was seen with. That rifle was essentially an M4 platform chambered in 7.62 NATO round.
The new rifle appears to be a different design and looks like to be a weird hybrid of G3 and MPT-76 rifle combo. Two most obvious features are non reciprocating charging handle and some better recoil mitigating system. Firing simple G3 in that manner would have kicked back the shooter a lot and automatic fire is also seems to be better controlled in the video. 7.62x51 inherently packs a lot of punch and recoil.
Pleased to see POF doing some actual and practical R&D and improving upon their Homegrown designs incrementally. This rifle as depicted in the video shows a lot of promising features rivaling the current global competition in its category. It would eventually all depend upon how it performs under the Army's torture tests.