[mythtv] [PATCH] pcHDTV: enable subchannel support
Edward.Wildgoose at FRMHedge.com
Tue Nov 4 09:58:33 EST 2003
> I did take a look through the DVB code a while back.
Be aware though that it had a very radical overhaul that was checked in a week or so ago.
> It seems to me
> that the DVB driver and/or hardware makes its own distinction between
> subprograms, whereas the pcHDTV driver is really just delivering the
> raw transport stream.
Hmm, kind of. The DVB stuff is basically the same, but the linuxtv guys have moved a lot of the common functionality into the driver level so you can actually request something more refined than "everything". However, the code "should" be able to handle a full TS, coming from a budget card say. The motivation for this feature is that the drivers only let you filter (I think) 8 pids, and so recording multiple channels from a single card could run into PID limits. By doing your own filtering you can get as many channels as you need from one card (well you probably only get one or two anyway, DVB has perhaps 4-8 channels per mux)
> And there is a bunch of stuff that's specific to
> ATSC in the details (like the embedded program guide data), even though
> the concepts are the same.
Sure. Although it looks like the guide data is pretty variable in the DVB implementation as well! DVB-T just broadcast now/next stuff and it's frequently out of date or broken anyway...
> Where I think the DVB and HDTV camps share the most common interest is
> in the user interface end of things -- I look forward to seeing that
> channel editor.
Perhaps. I would have thought though that in both cases you have a card which delivers a TS based mpeg stream to the backend. The only difference is resolution and probably some (non-trivial) implementation details as to exactly which parts of the TS stream are broken and implemented in non-standard ways... ;-)
It's worth having another look if you haven't glanced at the code for a while
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