Connected TV advertising impression volume on devices keeps rising -- set-top box/platforms Roku and Amazon Fire TV posted post big gains in the first quarter of this year versus the fourth-quarter 2020.

Roku rose 71% in CTV advertising impressions to 48 billion, while Amazon Fire TV is up 104% to 32 billion impressions, according to Samba TV, the TV viewing/household identify graph company.

Farther down the list: Samsung saw a 3% gain to just over 20 billion. Vizio is next, posting a 127% rise, to around 6 billion to 7 billion impressions.

Also-rans include Google, down 3% to around 4 billion; Apple TV up 25% to 3.5 billion, and LG, 127% higher to 3 billion.

Samba says the No. 1 advertiser by impressions in the first three months of the year was Discovery with 10.8 billion -- virtually all coming from its cable networks touting its new streaming service discovery+.

CBS was next at 7.5 billion. Those efforts include this year’s Super Bowl, the NCAA Men’s college basketball tournament in March, as well as promotion for ViacomCBS’ Paramount+ streaming service.

Geico followed CBS at 6 billion ad impressions. Then comes NBC, also at 6 billion impressions; ABC Television Network, 5.3 billion; Liberty Mutual, 5.1 billion; the Fox Television Network, 4.7 billion; Progressive Insurance, 4.5 billion; Domino’s, 4.1 billion; and T-Mobile, 3.4 billion.