st/va encode handle ntsc framerate rate control
st/va encode handle ntsc framerate rate control

Tested with ffmpeg and gst-vaapi. Without this bits per
frame is set way too low for fractional framerates.

v2: Mark Thompson: simplify calculation.
    Use float.

Signed-off-by: Andy Furniss <3f5e3d7738f5d472c0fa07afa7db27134193c377@gmail.com>
Acked-by: Christian König <c7ea837d7a46effe4232b086213468b8b31643bf@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler