Fix in-flight frame resize. (!20) · Merge requests · Async / VTK

when a frame dimensions are different than the previous frame, simply setting up a new encoder frame was not enough to tell the encoder to use the new widthxheight.
in order for it to work, reinitialize the encoder context. ffmpeg requires a new context when dimensions change.
fixed some typos
added vtkCodedVideoPacket::GetData() override that returns vtkUnsignedCharArray*

Fix in-flight frame resize.