[mythtv-users] Semi-OT: DVB in USA?

Todd nospam at tippyturtle.com
Tue Apr 4 21:28:54 UTC 2006


You are mixing terms...with respect to the wire.

You are using your PVR-150 to capture an analog signal from your Digital 
Cable box.  This is exactly what I am doing with my Dish Box.  I use and IR 
blaster to control the box, and send video (via Svideo) and Audio (via RCA 
Jacks) from the Digital Satellite (in your case, Digital Cable) box.  So you 
are capturing a digital cable signal after turning it into analog and back 
into MPEG2.

Someone corrected me earlier to say DVB-C is not QAM.  Technically true, but 
it seems the marketing geniuses that describe the ATSC cards say "does QAM" 
to mean "does DVB-C".  Check:
http://en.wikipedia.org/wiki/DVB
Notice DVB-C uses QAM (64 in general).  DVB-S (SHF) uses QPSK, DVB-T 
(VHF/UHF) uses COFDM and ATSC uses 8VSB.  The card I referenced:
http://mythic.tv/product_info.php?products_id=46
...does BOTH 8VSB and QAM....so it can deal with ATSC and DVB-C.

Anyway, to keep stuff Digital-Digital-Digital....aka MPEG2 through and 
through, use one of these Air2PC, Airstar, etc, type cards in the US.

If you want to do DVB-S and DVB-C, you are locked out of anything encrypted 
(in the USA).  Supposedly CableCards should fix this for DVB-C...but I doubt 
it for open source projects.  ATSC is never encrypted (that I know of), so 
you can get your locals in perfect MPEG2 (joke there...lossy)...but at least 
you don't have generation loss due to many MPEG2 to Analog to MPEG2 
conversions.

DVB-C Note #2:  I understand you aren't COMPLETELY locked out of encrypted 
DVB-C if you use firewire to control and capture video from you Digital 
Cable box.  (These means ONLY a fire wire connects your MythBackend to the 
Cable box; No analog RCA or SVideo cables.)  It seems every provider is 
different...some block "premium" channels via firewire, some don't.  I have 
no experience with this, so you will need to ask questions of someone who 
has done this.

Another note...you don't have to have a powerful machine to watch 
downcoverted recordings.  I quickly stopped watching LiveTV because (yes 
even the news) recording are WAY more convenient for me.  I just have HD 
content transcoded after the fact to MPEG4 (and rescaled to 800 wide).  It 
even plays on my EPIA M1000 frontend.  If you haven't made the paradigm 
change here are my tips:
-Get used to setting "No. of recordings to keep"
-Get used to setting "Priority"
-Get one additional ATSC card, you will never have a problem with prime time 
scheduling again.

...it is starting to get weird...it has been about 6 months since I have 
seen a commercial.  You don't realize how many daily references there are to 
tv commercials until you stop seeing them.  :-)

Clear as mud?...GREAT!  :-)

Todd

----- Original Message ----- 
From: "Steven Adeff" <adeffs.mythtv at gmail.com>
To: "Discussion about mythtv" <mythtv-users at mythtv.org>
Sent: Tuesday, April 04, 2006 10:13 AM
Subject: Re: [mythtv-users] Semi-OT: DVB in USA?


> On 4/4/06, Mark Johannessen <mfjlaw at gmail.com> wrote:
>> > Yeah, that's kind of what I want! Looks like I'll have to resort to
>> > digital cable through my PVR-150 for anything like that. My Myth
>> > Backend isn't powerful enough to handle HD down conversion, and my
>> > front-end can't do it on the fly.
>>
>> I'm a bit confused on this ... I though the PVR-xxx series cards can
>> capture analog streams (OTA or cable) but not digital streams (like DT
>> labelled channels whether through cable or OTA) and that is why people
>> are using the pcHD300 etc. type cards.
>>
>> Mark
>
> with a PVR card you output the digital channel from a
> cablebox/satelite receiver through SVideo output into the PVR card and
> use a ir blaster or serial connection to change channels.
>
> --
> Steve
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> mythtv-users at mythtv.org
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> 



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