Define "meld."

If they're encoding the ads and the content into the same video stream, which appears to be the proposal, your client still has access to the entire video stream and in fact must do so in order to play it.

Even if you're not going to be able to identify an ad on the raw binary level, and my proposal to do that was just spitballing anyway, the world is just absolutely chock-a-block full of audio and video content identification technologies that could be co-opted to identify specific ads, at which point your client could simply not play the section of the video stream containing them.