[mythtv-users] Backend setup for win-hvr-950Q

Raymond Wagner raymond at wagnerrp.com
Sat Jul 30 04:51:45 UTC 2011


On 7/29/2011 23:33, Barry Fawthrop wrote:
> tvtime works right out of the box (so to speak)

TVTime only works with analog framegrabbers.  Your card is an analog 
framegrabber and digital tuner in one.  While MythTV can handle V4L 
framegrabbers, as far as most of us around here are concerned, they are 
to be avoided at all costs.

Framegrabbers do just what it sounds like.  They capture raw frames, and 
store them temporarily in a location in memory.  TVTime then takes that 
frame, and copies it into your display buffer, and that's it.  It leaves 
audio passthrough up to the user.  That is what framegrabbers were 
designed to do, and in that scenario, they are cheap, effective, and 
work well.

Now we come to MythTV, and being a DVR, MythTV records everything.  
Instead of simply shifting some memory around, MythTV has to capture all 
that data, store it in some longer term buffer, encode it in real time 
to some compressed format, grab the audio either out of the tuner or 
through a separate sound card, encode it, and multiplex the two together 
while maintaining A/V sync.  There are a ton of pitfalls in this 
process, and are a never ending source of trouble to both the users and 
the developers.

What I have been directing you to configure is the digital side of that 
tuner, and if you just use that side and ignore the analog 'support' 
entirely, it will work great.  Cable providers will rebroadcast the 
local stations unencrypted in a manner that card can record.  They may 
offer more unencrypted, but that varies from region to region.  Silicon 
Dust offers a database of expected clear QAM channel lineups, 
search-able by zip code.

http://www.silicondust.com/support/channels/

If you want to record analog cable, you should use a hardware encoder.  
A hardware encoder does all that messy stuff described above in 
hardware, and offers MythTV a nice clean MPEG2 stream.  They are a bit 
more expensive, but what you pay in cost, you more than recover in ease 
of use.

http://www.mythtv.org/wiki/Analog_Hardware_Encoder_Cards


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