[mythtv-users] Possibly a "dumb" question

[Daniel Kristjansson]

On Fri, 2010-02-05 at 10:40 -0500, Jim Morton wrote:
> Can someone explain this to me? I just don't get it...
> 
> Myth records shows as mpeg or whatever is being broadcast with no 
> decoding or other changes effectively capturing it unaltered.
> During playback, Myth has a myriad of ways to process and render 
> video/audio to then deliver to the TV.
> Why can't it just stream the exact file to the TV and let the TV tuner 
> receive/decode/render/interlace/deinterlace it. In other words hand it 
> to the TV exactly as it were broadcast.

Heh, well you could. DVEO makes modulator cards in the TVB 590 line
that would allow you to transmit the signal so as to allow the
TV to receive it as if it were an over-the-air or cable broadcast.
But you would lose the ability to fast-forward, rewind, pause, etc.
There isn't really any interest in supporting such a limited rendering
method in MythTV. Plus, the market for these cards is not the typical
consumer, so they are professionally priced and supported.

Some of the older TV's have a firewire input which can take ATSC
directly, but as this is a de-facto depreciated input and handling
the OSD with this would be problematic this is also unlikely to
ever be supported.

Some of the newer TV's have an ethernet port and support something
called UPnP or DNLA. Some of those TV's will be able to play MythTV
content directly, again with fairly limited capabilities. There are
provisions in DNLA to support a real UI, but unfortunately they are
vendor specific and no one TV supports all the different methods.

No TV is going to support something like time-stretch, which is one
of MythTV's killer features.

PS MythTV doesn't just record what's on the wire, with frame-grabbers
it encodes the file as NuppelVideo which no one supports properly
except MythTV. And with encoder cards it records whatever format the
card supports, which in some cases is not supported by TVs. It's only
with digital cards that it records the active subset of what is on
the wire and rewrites the program information tables to exclude the
programs and private data streams it is not recording.

-- Daniel