OPPO Reno allegedly uses Nokia's OZO audio technology
OZO Audio has been developed by Nokia to enhance native sound quality on the videos captured on a smartphone's cameras. The company claims that the technology is capable, for example, of "full sonic richness" when recording on a phone. OZO Audio can also be used to edit the soundtrack on a device.
It is available for licensing to other companies and OEMs. This, then, may be why Nokia has claimed that OZO Audio is present on another brand's current flagship: OPPO's Reno. This phone has triple cameras, with an option on 10X hybrid zoom on more expensive SKUs.
Nokia has reportedly noted that the Reno series comes equipped with OZO in its first financial report for 2019. This publication seems to have a largely negative perspective of the company's performance at this point - which was, furthermore, "expected".
However, it is less clear why OPPO itself does not make any reference to OZO Audio in its own official material for the Reno line. This may have something to do with branding; however, that does not explain why it's happy to list Dolby Atmos for audio on the phones themselves among their selling points.