Re: www.badvista.org

I'm not 100% on this one but here is how I understand it and why
there might be some confusion here. Note I haven't checked out any of
the links below but have spent significant time mucking with high
definition sources so this should apply to HD in general, not
necessary Linux compatible HD devices:

Most modern hardware implementations of digital HD content have some
sort of DRM required. It maybe that some of the HD recording devices/
software for Linux don't support modern DRM (HDCP in this case) and
therefore can't record the content unless the provider (cable company/
satellite provider/Blu-ray player, etc.) disables the HDCP
negotiation. If HDCP is disabled then the receiving device can record
the content but many of the hardware vendors are now requiring that
HDCP be enabled and one by one cable/sat/etc. companies are enabling
HDCP on their platforms.

HDMI (and DVI in some cases) uses a protocol called HDCP in order to
prevent unauthorized devices from receiving the high definition
content stream. When the HDMI source is turned on it negotiates with
the next HDMI aware device, etc. down the chain all the way to the
recorder or display device. If a single device (other than a plain no-
logic switch/relay) in-between doesn't support HDMI or they are
running incompatible versions you will end up with no audio or video
being transmitted since the entire chain must be authenticated for
the video and audio to be sent over HDMI.

One of the ways I avoided DRM early on when I didn't have HDCP
compatible devices was to use source devices that did not enforce
HDCP. Normally the combination that I used was SPDIF audio w/ DVI or
Component video. Now I've given up and almost all my devices support
HDCP since it was becoming increasingly difficult to integrate new
components without it.

Component, VGA/HD-15, DVI (in some cases - modern DVI interfaces are
commonly HDCP enabled), analog audio, SPDIF/Coax interfaces etc. are
all sources which do not have HDCP so this makes it so if you can get
into the middle or have a device hanging off the cable or sat box you
can record the content in high definition. Many people that
experience compatibility issues with HDMI/HDCP between their products
end up switching back to Component video and non-HDMI digital audio
in order to record or display high definition content.

-Alan

On Jul 9, 2007, at 12:51 PM, Damien Hull wrote:

> I know 2 things. There are a lot of options and most of them don't do
> true HD.
>
> I checked out mythtv.org. I see they list a HD TV tuner card (pchdtv).
> There may be more HD support but I didn't dig that deep. Even if this
> tuner card lets you connect to the cable box ( not sure that it does )
> you won't get HD support. Even if your cable company offers HD
> content.
>
> I'm not sure how it all works but it has something to do with hardware
> and stealing. I think they configured HD cables etc... so you can't
> stick a recorder in the middle and get true HD. That would be stealing
> content.
>
> If you want a DVR that records HD content you need one that's built
> into
> the cable or sat box. That's my take on it.
>
> Oh, this is assuming that these so called HD cards/hardware is true
> HD.
>
>
> Arthur Corliss wrote:
>> On Mon, 9 Jul 2007, jonr@destar.net wrote:
>>
>>
>>>> Those open source guys are fast. Can you post a link to some
>>>> info. I
>>>> don't have HD anything but I would like to read about it.
>>>> ---------
>>>>
>>> http://mythtv.org
>>>
>>
>> I don't know squat about this stuff, but you can see HD hardware
>> already
>> supported on Linux here:
>>
>> http://www.linuxtv.org/wiki/index.php/ATSC_PCI_Cards
>>
>> --Arthur Corliss
>> Live Free or Die
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Received on Mon Jul 9 13:49:06 2007