[mythtv] [experimental patch] pchdtv bttv support

Daniel Thor Kristjansson danielk at mrl.nyu.edu
Tue Jan 18 08:57:14 EST 2005

On Mon, 17 Jan 2005, Isaac Richards wrote:
]Why not just switch channel objects, too?  I don't think it'd be difficult.  
]What troubles were there from the scheduler?  I don't see how this is any 
]different than a normal card with two different channel lineups attached to 
]two different inputs.
]> It 
]> surprisingly turned out more complex. I also needed to keep two
]> different ring buffers in TVRec or do some fancy footwork.
]And again, why? =)  I don't see the need for two ringbuffers, as long as the 
]player's modified to switch appropriately (which would be easy)...
]You're breaking the entire design of tvrec.cpp & the database layout though.  
]I don't like the concept at all.

So the pchdtv driver advertises two /dev/v4l/video cards, so you need to 
add another column for extra device auxvideodevice. But I went back and 
looked at my first pchdtv w/bttv patch and it looks like the problem 
was that I also created another default input auxdefaultinput. This ment 
I could keep the old scan for inputs code, but also caused complications 
in the scheduler where I had to check the inputs connected to the 
regular input and the auxiliary input. But if I change the input scanner 
to prepend "Digitial:" to inputs scanned of the the ATSC input and 
"Analog:" to the inputs scanned of the NTSC input then the sceduler 
doesn't have to change, and the changes to tv_rec are at about the same.
I have to change recorderbase to allow for an extra parameter, the 
auxvideodevice, and I need to make minor make changes in about the same 
places, but the schema won't really change. 

I'm not sure if this will impact the player though, can it cope with 
getting nuppelvideo one minute and mpeg2 the next? My guess is yes, but 
I'm not sure.

If a different capture card has two sets of vbi and audiodev devices 
then we would need to duplicate those as well, which is an arguement 
for the multiple cards w/one tuner setup I devised. But I think this 
will work for PVR cards with radio, if we are willing to put the radio 
device in the auxvideodevice field (which I could name auxdevice).

I'll send in the patches unrelated to the pchdtv that I generated in 
the process, so there isn't too much drift between my patches and the 
cvs. And then I'll try this auxdevice virtual inputs approach. Virtual 
inputs will be needed to allow recording multiple streams per mux 

-- Daniel

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