A native video ad is sometimes defined as an independent user-initiated video ad on a video platform like YouTube.
Thus, consumers choose to see a native video ad as opposed to pre-roll video ads that are auto-played. Native video ads have not limit on length.
Native video ads have proven better impact but they have also an audience issue. To have a significant amount of views, a real native video ad needs to be viral or promoted. Users seldomly choose to see a classic commercial on video platforms outside pre and mid-roll formats.
Note that some marketers consider all video ad as being native ads on video platforms. By this larger point of view, native video ads are opposed to classic banner ads.
See also native advertising.