[mythtv] ivtv support classes and deviceIsMpegFile

[Chris Pinkham]

> I've just been poking around in mpegrecorder.cpp, which I assume is used
> to support the hardware MPEG encoding cards available. However, I'm more
> interested by the presence of the deviceIsMpegFile flag. It looks like

deviceIsMpegFile was put in primarily to aid in development so that I could
work on mythbackend from my laptop with no (at-the-time) USB supported
capture device and hence the reason it is undocumented since it wasn't
meant for production use.  The code is in mpegrecorder.cpp so the source file
must be mpeg2 since mpegrecorder examines the datastream in order to
track and store positionmap info.  I'll let others comment on your general
direction on recording multicast broadcasts, but I think it would probably
be better to include this as another recorder class rather than trying to
hack it into mpegrecorder.  Your code will need to handle "channel" changing,
etc. and could potentially be used to "record" non-video broadcasts as well,
such as mp3 radio broadcasts.

I'll let others comment more as I know the idea of recording streams or
non-video content has come up before.

-- 
Chris