Re: www.badvista.org

To go one step further in my explanation:
If I were on a computer whether running Windows, Mac, LInux, etc. and
did not want DRM but wanted high definition recording capabilities I
would find a way to get digital audio over Coaxial or SPDIF and
figure a method to get Component or VGA video (VGA and component use
the same encoding if I remember correctly so you can get converters/
cables to go back and forth) into my computer from the high
definition source since those will not be protected. Almost, if not
all the devices I have hooked up still allow HD content to be sent
unprotected via analog outputs and the quality sacrifice is minimal
(negligible to most people?). The challenge with using DVI is that
HDCP is now optional and many of the modern devices are enforcing
HDCP use over it, if it is an option it would be preferred over any
analog format. If you are planning on using GCI cable as a source
multiple models of GCI cable boxes (Motorola and Pace) have Firewire
ports, which people have been using to capture video off of for quite
awhile now. I've only seen it being used under Windows but some of
the guys I spoke with state that MythTV also supports it.

I haven't done any reading on HDCP hacking or if there is a work-
around market available but if I demanded digital signal from end to
end then I would suggest finding a HDCP compliant solution since you
are bound to run into issues if you don't unless you have a reliable
work-around or hack (or you have access to a cable box with
firewire :^)). At first I didn't want to accept that HDCP enabled
inputs would become the norm but it's become clear that unless you
want to spend lots of time trying to find work-arounds the solution
above of using Component video and digital (but non-protected) audio
or a proper digital end-to-end w/ HDCP solution is the way to go
IMO. Many new computers are starting to come with HDMI capability
but the challenge would be finding good drivers/software to make it a
useful interface under linux I would suspect.

There are many receivers and things on the market that have HDMI and
analog inputs/outputs, many modern ones I have seen will not allow a
incoming protected signal to be output any interfaces that are not
HDCP aware. If you are thinking about buying a middle-man device to
intercept a copy of the data you will want to read the fine print and
make sure that there will be a method to get the data out of the
receiver without HDCP, otherwise you are back at the step of HDCP
enabling your computer.

One other thing worth noting - even though older non-protected
digital interfaces are capable of transmitting some of the highest
resolution images and best audio formats some vendors have started
limiting the types of audio and video that will be transmitted over a
non-protected interface. So far I haven't seen any real issues due to
this but you can find on the web discussions of Blu Ray players and
what audio outputs they will strip if using non-HDMI output or what
limitations HD-DVD has tried to put on video output over non-
protected interfaces (big discussion of this when the Xbox HD drive
was released but it turned out to be mostly junk - HD-DVD has the
option to disable analog HD output but last time I researched it
didn't appear anyone was turning that limitation on yet).

-Alan

On Jul 9, 2007, at 2:04 PM, jonr@destar.net wrote:

> Quoting "Alan C." <r.andom@noshut.com>:
>
>> 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
>>
>
> Good write up Alan. I know the DRM issue was twice shot down in =20
> congress and the next step was to pressure the manufactures into =20
> building it directly into their devices. There was a big rush to
> get =20
> HD cards that did not have the restrictions before the first vote
> in =20
> Congress. You can still get the equipment but it is becoming =20
> increasingly more difficult to do so.
>
> Jon
>
>
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Received on Mon Jul 9 17:33:54 2007