GNU/Linux... Graphics cards... HDTV... HDCP...????

Hello,
I'm quite confused about the whole HDCP thing lately.
I want to build a small HTPC system.
The lowest spec Intel C2D, mobo, 1GB of RAM, nVidia GeForce 8500 with
passive cooling, HD DVB-T tuner... and most importantly - an HDTV.

Now, I am quite confused about the whole copy protection thing...
What's this HDCP? As far as I've researched, it may be evident that
getting the full resolution that you pay for is not possible unless
the graphics is specialised or something?
How about DVI to HDMI connectors or such?
I want to run in full HD, will I be able to use the full quality
that's available?
Is it better to go for an unclear HDMI connection 32" television of
720p support or 24" monitor with a 1920x1200 resolution and a DVI port
without Digital Restrictions Management?

Need advice.

Thank You.

On Fri, 23 Nov 2007 11:10:08 -0800 (PST) Drakas wrote:

| I'm quite confused about the whole HDCP thing lately.
| I want to build a small HTPC system.
| The lowest spec Intel C2D, mobo, 1GB of RAM, nVidia GeForce 8500 with
| passive cooling, HD DVB-T tuner... and most importantly - an HDTV.
|
| Now, I am quite confused about the whole copy protection thing...
| What's this HDCP? As far as I've researched, it may be evident that
| getting the full resolution that you pay for is not possible unless
| the graphics is specialised or something?
| How about DVI to HDMI connectors or such?
| I want to run in full HD, will I be able to use the full quality
| that's available?
| Is it better to go for an unclear HDMI connection 32" television of
| 720p support or 24" monitor with a 1920x1200 resolution and a DVI port
| without Digital Restrictions Management?

HDCP is a method that allows an equipped player to verify that the display
is appropriately secured so that you have no easy way to acquire the high
definition video outside the scope of the content producer's control. The
player will check if the display has a valid key (as provided by the disc
media itself, which allows future discs to revoke keys for displays that
are discovered to have a "hole"). It will then encrypt the digital signal
sent across the HDMI cable so you can't get anything useful from tapping
those wires. If the verification cannot be established, usually the player
will be allowed to display the video at a reduced, probably standard, level
of resolution. Analog output will likely be considered equivalent to an
unverified display (because you can tap that directly and reconvert to
digital nearly as good as the original ... with the right investment in
hardware).

In a home computer, the computer software acts as the player. That software
has to go a step further in verification to be sure you have not done anything
to intercept the video in software, such as by substituting a driver. So it
will do things like checking driver signatures to be sure the expected driver
is running and in control. These verifications will also be repeated often.
Only secure player software, display drivers, and video card will be allowed.
And the display itself will still be verified as in the case when it is not a
computer that is involved.

GNU/Linux is an open system and thus, is too easy for the computer owner to
do as they wish, including intercepting the video and audio in it's original
digital format. The movie studios, therefore, cannot control your computer,
and so, will not authorize any keys that might ever be associated with Linux
based media software.

Note that this only applies to HDCP protected content. Many independent
content producers will choose not to use HDCP, either because they are as
much opposed to this as informed viewers are, or because they don't expect
financial losses to be at the level the licensing of HDCP would cost them.

You will likely need to use a separate HDCP equipped player, or a Microsoft
Windows Vista based computer system (and I believe only the Home editions
will have the media software). Then if you still want to have full control
over your own computer for other content, then you'll have GNU/Linux, too.
In my own case I expect to have a combination of a Linux based computer and
a direct standalone XX-DVD player or two in order to be able to watch any
and all content I might buy. Most of this is still on hold for a couple
more years to see where the market and technology deployments are going.
I do not intend to run any Microsoft Windows for any of this; it is just
too untrustable.

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / |
|------------------------------------/-------------------------------------|

Thanks for explaining.
Lol, that's real M$FKT waste!
How about being able to fake the "keys" or something? I'm not sure how
this verification works...

So just to reiterate: 1) source sends a "code" to the TV 2) The TV
"verifies" the code and sends a resolution change to the source 3)
Source sends at a lower resolution 4) if 2 was unsuccessful, the TV
will rescale the received data 5) Display it

Or am I wrong?

If I just want to use my PC on an HDTV, will it work at full
resolution?
Just normal desktop stuff....

On Nov 23, 9:10 pm, wrote:
On Fri, 23 Nov 2007 11:10:08 -0800 (PST) Drakas wrote:

| I'm quite confused about the whole HDCP thing lately.
| I want to build a small HTPC system.
| The lowest spec Intel C2D, mobo, 1GB of RAM, nVidia GeForce 8500 with
| passive cooling, HD DVB-T tuner... and most importantly - an HDTV.
|
| Now, I am quite confused about the whole copy protection thing...
| What's this HDCP? As far as I've researched, it may be evident that
| getting the full resolution that you pay for is not possible unless
| the graphics is specialised or something?
| How about DVI to HDMI connectors or such?
| I want to run in full HD, will I be able to use the full quality
| that's available?
| Is it better to go for an unclear HDMI connection 32" television of
| 720p support or 24" monitor with a 1920x1200 resolution and a DVI port
| without Digital Restrictions Management?

HDCP is a method that allows an equipped player to verify that the display
is appropriately secured so that you have no easy way to acquire the high
definition video outside the scope of the content producer's control. The
player will check if the display has a valid key (as provided by the disc
media itself, which allows future discs to revoke keys for displays that
are discovered to have a "hole"). It will then encrypt the digital signal
sent across the HDMI cable so you can't get anything useful from tapping
those wires. If the verification cannot be established, usually the player
will be allowed to display the video at a reduced, probably standard, level
of resolution. Analog output will likely be considered equivalent to an
unverified display (because you can tap that directly and reconvert to
digital nearly as good as the original ... with the right investment in
hardware).

In a home computer, the computer software acts as the player. That software
has to go a step further in verification to be sure you have not done anything
to intercept the video in software, such as by substituting a driver. So it
will do things like checking driver signatures to be sure the expected driver
is running and in control. These verifications will also be repeated often.
Only secure player software, display drivers, and video card will be allowed.
And the display itself will still be verified as in the case when it is not a
computer that is involved.

GNU/Linux is an open system and thus, is too easy for the computer owner to
do as they wish, including intercepting the video and audio in it's original
digital format. The movie studios, therefore, cannot control your computer,
and so, will not authorize any keys that might ever be associated with Linux
based media software.

Note that this only applies to HDCP protected content. Many independent
content producers will choose not to use HDCP, either because they are as
much opposed to this as informed viewers are, or because they don't expect
financial losses to be at the level the licensing of HDCP would cost them.

You will likely need to use a separate HDCP equipped player, or a Microsoft
Windows Vista based computer system (and I believe only the Home editions
will have the media software). Then if you still want to have full control
over your own computer for other content, then you'll have GNU/Linux, too.
In my own case I expect to have a combination of a Linux based computer and
a direct standalone XX-DVD player or two in order to be able to watch any
and all content I might buy. Most of this is still on hold for a couple
more years to see where the market and technology deployments are going.
I do not intend to run any Microsoft Windows for any of this; it is just
too untrustable.

--
|---------------------------------------/-----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / |
|------------------------------------/--------------------------------------|

On Fri, 23 Nov 2007 11:10:08 -0800, Drakas wrote:

I'm quite confused about the whole HDCP thing lately. I want to build a
small HTPC system.
The lowest spec Intel C2D, mobo, 1GB of RAM, nVidia GeForce 8500 with
passive cooling, HD DVB-T tuner... and most importantly - an HDTV.

Now, I am quite confused about the whole copy protection thing... What's
this HDCP? As far as I've researched, it may be evident that getting the
full resolution that you pay for is not possible unless the graphics is
specialised or something? How about DVI to HDMI connectors or such? I
want to run in full HD, will I be able to use the full quality that's
available?

I'd suggest you get some help from someone in Europe about how it affects
DVB-T broadcast. I assume that's where you are since DVB-T isn't used here
in the US. I've been running MythTV for a couple of years here and haven't
run into any problems. AFAIK, libdvdcss takes care of all that drm crap
for dvd's. At least it has for the few DVD's I've played.



--
Want the ultimate in free OTA SD/HDTV Recorder? http://mythtv.org
My Tivo Experience http://wesnewell.no-ip.com/tivo.htm
Tivo HD/S3 compared http://wesnewell.no-ip.com/mythtivo.htm
AMD cpu help http://wesnewell.no-ip.com/cpu.php

On Fri, 23 Nov 2007 13:24:32 -0800 (PST) Drakas wrote:

| Thanks for explaining.
| Lol, that's real M$FKT waste!
| How about being able to fake the "keys" or something? I'm not sure how
| this verification works...
|
| So just to reiterate: 1) source sends a "code" to the TV 2) The TV
| "verifies" the code and sends a resolution change to the source 3)
| Source sends at a lower resolution 4) if 2 was unsuccessful, the TV
| will rescale the received data 5) Display it
|
| Or am I wrong?

I do not know the exact protocol. But what you suggest has flaws.
The big flaw is that the source has to immediately trust the display
without knowing anything about the display. A device could be made
to always give a "highest resolution" response to any query if that
protocol were in use.

A secure protocol could involve the display providing its public part
of a key, and encrypting a random token provided by the source and
giving that back as proof it holds the private part of the key. The
player can decrypt that using the public key and thus know the display
really has that key. It can then look up that key in the table of
keys on the disc to see if it is good or bad. If it is good, then
the source will generate a random cipher key, encrypt that key with
the display's public key, and send it to the display. The display
would decrypt the key to get the random cipher again. Video would be
sent encrypted with the random cipher key. Periodically the process
would be repeated so new cipher keys would be regenerated often to
thwart attemps to crack that key.

I do not know if this is the protocol actually used, but it could be
the basis for one that, with a few other features, could work and may
be secure enough for the content involved.


| If I just want to use my PC on an HDTV, will it work at full
| resolution?
| Just normal desktop stuff....

If the PC is sending UNencrypted content to the display, that's fine.
It will work. HDCP won't be involved. A normal PC monitor attached
via DVI is essentially the same thing. Your PC graphical desktop
content won't be encrypted, so with a DVI to HDMI cable, you can
connect the PC to the big screen TV and use it that way. I recommend
setting the PC graphical geometry to the native geometry of the display.
In most cases it will just do that automatically for you, in Windows or
in Xorg under Linux or BSD.

If you want to play HDCP protected video from a BR/HD-DVD through your
PC, that's when things get hairy.

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / |
|------------------------------------/-------------------------------------|

"Drakas" wrote in message
...
Hello,
I'm quite confused about the whole HDCP thing lately.
I want to build a small HTPC system.
The lowest spec Intel C2D, mobo, 1GB of RAM, nVidia GeForce 8500 with
passive cooling, HD DVB-T tuner... and most importantly - an HDTV.

Now, I am quite confused about the whole copy protection thing...
What's this HDCP? As far as I've researched, it may be evident that
getting the full resolution that you pay for is not possible unless
the graphics is specialised or something?
How about DVI to HDMI connectors or such?
I want to run in full HD, will I be able to use the full quality
that's available?
Is it better to go for an unclear HDMI connection 32" television of
720p support or 24" monitor with a 1920x1200 resolution and a DVI port
without Digital Restrictions Management?

About HDCP:

HDCP is the DRM for HD sources, such as Blu-Ray, HD DVD, and HD content from
cable and sat. It is hardware based. The source communicates with the
display via the HDMI or DVI connections. HDCP does not support component
and VGA connections, so encrypted HD content will not play across those
connections. HD sources such as OTA and unencrypted QAM play fine across
VGA and component. Computer monitor cloning works fine across VGA, DVI, and
HDMI.

If you have a Blu-Ray or HD DVD drive, you should be able to view the
content on an HDTV (while playing the content in some sort of media
software) via cloning without worrying about HDCP, but I'm not certain of
this having not tried it myself.

About HTPC:

What you need is a video card that supports HDCP. Most (all?) video cards
that have an HDMI port will have HDCP support. Many newer cards with DVI
also support HDCP. Check the box! Your Blu-Ray or HD DVD drive will now be
able to pass the signal to any HDCP display, be it a monitor you have on
your desk or your HDTV in your living room. You do not need an
HDCP-compliant video card to display computer content on your HDTV. To get
a good picture, you need to use DVI or HDMI, but VGA looks ok, too. Don't
even bother with composite or S-video. Most mobos with DVI out do not
support HDCP, but there are a few, especially in the mini-ATX form factor,
that do and are intended for HTPC usage.

About Linux:

Since the HDCP handshaking is handled in the hardware connections between
the card and the monitor, I don't *think* that OS or drivers should be an
issue. However, you should go to the many Linux websites or newsgroups and
ask. Since it is specialized knowledge, those places would probably offer
the best insight. Unless we have a resident Linux/HDTV resident here.

steveo

I still don't get it.
So you're saying that the sender of data has to verify the receiver's
authenticity?
Or is it pretty much both ways?
Borked
On Nov 24, 10:34 am, "steveo" wrote:
"Drakas" wrote in message

...





Hello,
I'm quite confused about the whole HDCP thing lately.
I want to build a small HTPC system.
The lowest spec Intel C2D, mobo, 1GB of RAM, nVidia GeForce 8500 with
passive cooling, HD DVB-T tuner... and most importantly - an HDTV.

Now, I am quite confused about the whole copy protection thing...
What's this HDCP? As far as I've researched, it may be evident that
getting the full resolution that you pay for is not possible unless
the graphics is specialised or something?
How about DVI to HDMI connectors or such?
I want to run in full HD, will I be able to use the full quality
that's available?
Is it better to go for an unclear HDMI connection 32" television of
720p support or 24" monitor with a 1920x1200 resolution and a DVI port
without Digital Restrictions Management?

About HDCP:

HDCP is the DRM for HD sources, such as Blu-Ray, HD DVD, and HD content from
cable and sat. It is hardware based. The source communicates with the
display via the HDMI or DVI connections. HDCP does not support component
and VGA connections, so encrypted HD content will not play across those
connections. HD sources such as OTA and unencrypted QAM play fine across
VGA and component. Computer monitor cloning works fine across VGA, DVI, and
HDMI.

If you have a Blu-Ray or HD DVD drive, you should be able to view the
content on an HDTV (while playing the content in some sort of media
software) via cloning without worrying about HDCP, but I'm not certain of
this having not tried it myself.

About HTPC:

What you need is a video card that supports HDCP. Most (all?) video cards
that have an HDMI port will have HDCP support. Many newer cards with DVI
also support HDCP. Check the box! Your Blu-Ray or HD DVD drive will now be
able to pass the signal to any HDCP display, be it a monitor you have on
your desk or your HDTV in your living room. You do not need an
HDCP-compliant video card to display computer content on your HDTV. To get
a good picture, you need to use DVI or HDMI, but VGA looks ok, too. Don't
even bother with composite or S-video. Most mobos with DVI out do not
support HDCP, but there are a few, especially in the mini-ATX form factor,
that do and are intended for HTPC usage.

About Linux:

Since the HDCP handshaking is handled in the hardware connections between
the card and the monitor, I don't *think* that OS or drivers should be an
issue. However, you should go to the many Linux websites or newsgroups and
ask. Since it is specialized knowledge, those places would probably offer
the best insight. Unless we have a resident Linux/HDTV resident here.

steveo