[mythtv] suggestion for rewinding in mythtv

[Torbjörn Jansson]

> In other words, the videocard input should always put data at the
> end of the ring buffer.  Channel changes shouldn't affect that.
> Where the frontend is reading from the ringbuffer shouldn't affect
> that, either. 
> 
> As the channel change is just an ioctl I've always found it strange
> that the ringbuffer resets itself during a channel change.
> 

What if you change to a channel on a different card? Then the stream may be
of another type/size, like when switching from analog card to a dvb card.

I woud be very happy if the ringbuffer didn't reset after each channel
change, it woud make things a lot easier for implementing channel changing
support for the windows filters I have written.
Just keeping the nuv file header in the ringbuffer after a reset woud also
help.