That is a good question. And strangely not as straight forward as I might like. "RGB" is 8 bit but video is not encoded with RGB, it is encoded YbCbCr [1], and the conversion from Chroma space to RGB space is fractional and depends on the Kr and Kb constants.
The math supports converting a YbCbCr 'pixel' into a 30 bit RGB pixel if your conversion constants allow for it. What is unclear is when quantization noise from the compression of the chroma signal shows up as bit instability in the resulting conversion cycle.
The math supports converting a YbCbCr 'pixel' into a 30 bit RGB pixel if your conversion constants allow for it. What is unclear is when quantization noise from the compression of the chroma signal shows up as bit instability in the resulting conversion cycle.
[1] http://en.wikipedia.org/wiki/YCbCr