fit

What the picture is drawn into, which the player's own choice of variant follows (#447): HDR over SDR when the output shows HDR, and no variant larger than the smallest one that fills the drawn area without being scaled up. maxBitrate and maxVideoHeight still apply on top. Null, the default, has the player fill it at each open, and at each step up, from the renderer it draws into; with no renderer there is no cap and SDR is preferred. Set it to choose for the player, for example to plan for full screen before the view grows. VariantFit() keeps no cap and prefers SDR.