[mythtv-users] Various questions

[Kevin Kuphal]

kteague at speakeasy.net wrote:

>Good day Ladies and Gent's,
>
>Long time lurker, first time poster with a few questions up my sleeve regarding hardware requirements for my type of setup.  
>
>Service Provider: DirecTV (from here on, referred to as D*)
>Video Format: NTSC
>Receiver: Any HD capable D* receiver
>Television: Westinghouse LVM-37w1
>
>1. From what I've gathered, since the DirecTV receivers have tuners in them, I do not need a tuner for my MythTV box.  Is this correct?
>  
>
Sort of.  You need a card that can capture from s-video or composite 
since this is the only output you can get from your DirecTV receiver 
(unless they offer one with firewire).  Most cards that have this (PVR 
series from Hauppauge, etc) also have a tuner so you basically are 
getting both for the price.

>2. I would like to record HD stuff, however, it appears that the only way to do this is via encoding with CPU overhead (no hardware encoders), as there are no video capture cards (supported under Linux) that can perform hardware HD encoding.  I did some reasearch on chipsets used on the Hauppauge PVR-500, and it appears the maximum encoding resolution they support is SD.  Now this is where it becomes very confusing.  
>  
>
You can record HD without software encoding using an HD-3000 or Air2PC 
card.  But these work with over-the-air HD signals from an Antenna.  
These have nothing to do with your DirectTV system, which, per #1, must 
be captured using S-video/composite input to your capture card (software 
or hardware)

>3. Are there any hardware encoding cards supported under Linux to encode the captured streams to MPEG4?  If so, does MythTV support this?  I know there's a Matrox USB device that can do this, but I would prefer something internal to the PC.
>  
>
Yes.  I believe the Plextor cards can do hardware MPEG-4 encoding on Linux.

>4. Output -- does MythTV output through the capture card?... or through the video card?... or do I have my choice?  I would like to use DVI and keep everything in the digital domain.
>  
>
Video card.  Highly recommend nVidia card of some kind since ATI has 
poor linux support.

>5. With the front end/back end arch., where are the encoder cards installed?  In the front or back end?
>  
>
They are installed where a mythbackend process runs.  This can be on a 
standalone master backend, a combination frontend/backend or even a 
slave backend working with a master.

>6. With the FE/BE arch., can the programs be recorded on the FE, then x-fer'd to the BE when the program is done recording?  I fear that a temporary network failure could disrupt a program recording.  Having it record on a small FE box, then x-fer'd later (or in chunks as the program is recording) to the BE, it can take advantage of resuming a failed upload to the BE.  Streaming the data has its limits.
>  
>
It is usually best to have all backends write to common disk using an 
NFS mount.  This avoids problems where the slave goes offline taking 
recordings with it.

>7. With the video scaling capabilities, could I get MythTV to constantly upscale all signals to 1080p?  For example, lets say I'm watching SDTV (480i), will it upscale that to 1080p?  Then, lets say I change to a channel that's outputting HDTV (720p or 1080i), will it automatically know to upscale those to 1080p?... or will I have to fiddle with MythTV each time I switch channels that output different scan rates?
>  
>
Not sure.  Someone else might answer this better.

Kevin