made frame.time_base accessible to user.
made frame.time_base accessible to user.

danielballan/PyAV,markreidvfx/PyAV,markreidvfx/PyAV,PyAV-Org/PyAV,pupil-labs/PyAV,xxr3376/PyAV,PyAV-Org/PyAV,mcpv/PyAV,mcpv/PyAV,mikeboers/PyAV,markreidvfx/PyAV,xxr3376/PyAV,xxr3376/PyAV,mcpv/PyAV,pupil-labs/PyAV,pupil-labs/PyAV,danielballan/PyAV,danielballan/PyAV,pupil-labs/PyAV,mikeboers/PyAV