mythtv and digital tv

[Frank DiPrete]

Jarod Wilson wrote:
> On Fri, 2008-07-25 at 07:11 -0400, Frank DiPrete wrote:
>> Ben Scott wrote:
>>> On Thu, Jul 24, 2008 at 6:36 PM, Frank DiPrete <fdiprete at comcast.net> wrote:
>>>> I like the HDHomeRun card ...
>>>   Just to make sure it's clear, the HDHomeRun isn't a card, it's an
>>> external box (about the size of a cigar box).  It uses a wall-wart
>>> type power supply transformer.
>>>
>>>> If the card had hardware encoding it would be perfect.
>>>   Encoding or decoding?
>> Encoding on the backend where the card goes.
>>
>> http://www.pchdtv.com/hd_5500.html
>>
>> The HD-5500 Hi Definition Television PCI Card is an universal PCI 2.2 
>> compliant card. The card receives NTSC, ATSC and Cable/QAM Signals and 
>> converts them to digital streams which are transported across the PCI 
>> bus. Display and MPEG2 decoding are done on the host computer
>>
>>>   For digital broadcast -- be it cable or ATSC OTA -- the stream is
>>> already encoded and compressed as part of the transmission process.
>>> There's no need for an encoder.
>>>
>> The description isn't clear about writing the streams to disk.
>>
>> The goal is to write mpeg2 files to the server for playback like the 
>> pvr-250 does via its encoder. I'd like to believe that the term "digital 
>> streams" means mpg2/aac but the term "digital streams" isn't defined on 
>> the site. I'll check some mythtv sites about this card to see what is 
>> involved.
> 
> "Digital streams" definitely means mpeg2 here. HDTV (and all digital
> video) over the air and on cable in the US is always mpeg2, encoded as
> such as the head end. Digital tuner cards more or less simply tune into
> a broadcast mpeg2 transport stream and dump it to disk.
> 
>>>   For decoding, I believe you'd still be able to use the "small quiet
>>> diskless box frontend".  The one thing I'm not sure about is: I expect
>>> not all hardware decoders are created equal.  It may be the decoder in
>>> your front-end box can't handle this new-fangeled high-def stuff.
>>>
>> The only prediction I have here is "probably OK". playback of the 
>> recordings I make today (ntsc analog to mpg2/aac at 48K sampling - file 
>> is a bout 2G per hour) takes 25% of the via cpu while using the mpeg 
>> decoder chip.
> 
> Depends heavily on the generation of your video controller... Many of
> the unichrome video chipset mpeg2 decoders can't handle larger than
> 720x480 streams. I forget which one is which anymore, but the first-gen
> one on an EPIA M10000 board definitely doesn't cut it (I have one). I
> believe unichrome pro II definitely *should* be able to, others, not
> sure..
> 
> 

crap! I have an M1K
super valuable info.