[ltp] FYI -- New ThinkPad T22 model for Linux includes DVD movie playback
Keith Frechette
linux-thinkpad@www.bm-soft.com
Mon, 16 Apr 2001 14:11:28 -0400
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This is an FYI, since I'm not aware that anybody noticed our success in
rolling out "legal" Linux DVD movie playback with our ThinkPad models.
The IBM ThinkPad T22 laptop computer was released in early April 2001. For
the Linux model, we were finally able to incorporate legitimate DVD movie
playback, using an application called LinDVD, created by InterVideo, Inc.
I had been working with InterVideo since last April (when they first
publicly announced their intent to deliver DVD movie support on Linux),
and all the pieces finally came together. I've included some anecdotal
information below for your information / amusement.
To implement legal Linux DVD movie playback support on a ThinkPad laptop
that includes an "S-Video out" port, we had to overcome some very
*interesting* hurdles. (While I can say "interesting" now, several months
ago I would have chosen a different word. :-)) The obvious requirement
that we had was to take adequate measures to protect the copyrights
associated with DVD movie titles. For example, enabling the user to
transfer DVD movies to other media (video tape, for example) via the
S-Video port would likely have triggered a flood of lawsuits. (Although
there may have been some happy Linux users!)
The primary hurdles were: 1) no standardized way for implementing
Macrovision (copy protection) on Linux, and 2) open-sourced X servers
could easily be hacked to disabled the necessary copy protection.
1) For laptops, the primary mechanism for stopping DVD movie piracy over
the S-Video port is to encode the out-going video signal using
Macrovision. Under Windows, the video driver architecture provides a
standard mechanism that allows DVD playback apps to tell the video driver
to enable Macrovision encoding when playing a protected DVD title. Under
Linux, no such standard exists. Fortunately, IBM, S3, and InterVideo were
able to come up with an interface that allows the LinDVD app to
communicate with S3's driver for controlling Macrovision. Perhaps in the
future the Linux community will define a standard interface for this,
possibly taking advantage of some of the work we did.
2) Under Windows, the natural place to put the actual Macrovision control
logic is in the video driver. Under Linux, however, video drivers (X
servers) are generally open-sourced, so handling Macrovision control logic
in the video driver is not appropriate. Instead, the code is placed in a
separate, binary-only, kernel driver. While this provides adequate
protection, it does tie the Macrovision support to specific kernels.
Hopefully we can resolve that in the future by packaging the Macrovision
control logic into a user-mode driver (e.g. a daemon running as root,
which has access to I/O space).
In short, releasing DVD movie playback for Linux was not as simple as it
initially seemed. However, with the constant cooperation of all the
parties involved, we were able to work through the issues. It excites me
when diverse teams work cooperatively together toward the common goal of
improving the end-user experience. And I suppose that's what has drawn me
to Linux.
So, we did it! I hope that our success helps to raise the bar just a
little, that in the future DVD movie support on Linux will be commonplace,
and that we can say to Windows users, "DVD movie playback -- yeah, we've
got that."
-- Keith
Keith Frechette
Linux Development Lead, Mobile Computing Options and Software Development
IBM Research Triangle Park, North Carolina
kfrechet@us.ibm.com / 919-543-3761 / TieLine:441-3761
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<br><font size=2 face="sans-serif">This is an FYI, since I'm not aware that anybody noticed our success in rolling out "legal" Linux DVD movie playback with our ThinkPad models.</font>
<br>
<br><font size=2 face="sans-serif">The IBM ThinkPad T22 laptop computer was released in early April 2001. For the Linux model, we were finally able to incorporate legitimate DVD movie playback, using an application called LinDVD, created by InterVideo, Inc. I had been working with InterVideo since last April (when they first publicly announced their intent to deliver DVD movie support on Linux), and all the pieces finally came together. I've included some anecdotal information below for your information / amusement.</font>
<br>
<br><font size=2 face="sans-serif">To implement legal Linux DVD movie playback support on a ThinkPad laptop that includes an "S-Video out" port, we had to overcome some very *interesting* hurdles. (While I can say "interesting" now, several months ago I would have chosen a different word. :-)) The obvious requirement that we had was to take adequate measures to protect the copyrights associated with DVD movie titles. For example, enabling the user to transfer DVD movies to other media (video tape, for example) via the S-Video port would likely have triggered a flood of lawsuits. (Although there may have been some happy Linux users!)</font>
<br>
<br><font size=2 face="sans-serif">The primary hurdles were: 1) no standardized way for implementing Macrovision (copy protection) on Linux, and 2) open-sourced X servers could easily be hacked to disabled the necessary copy protection.</font>
<br>
<br><font size=2 face="sans-serif">1) For laptops, the primary mechanism for stopping DVD movie piracy over the S-Video port is to encode the out-going video signal using Macrovision. Under Windows, the video driver architecture provides a standard mechanism that allows DVD playback apps to tell the video driver to enable Macrovision encoding when playing a protected DVD title. Under Linux, no such standard exists. Fortunately, IBM, S3, and InterVideo were able to come up with an interface that allows the LinDVD app to communicate with S3's driver for controlling Macrovision. Perhaps in the future the Linux community will define a standard interface for this, possibly taking advantage of some of the work we did.</font>
<br>
<br><font size=2 face="sans-serif">2) Under Windows, the natural place to put the actual Macrovision control logic is in the video driver. Under Linux, however, video drivers (X servers) are generally open-sourced, so handling Macrovision control logic in the video driver is not appropriate. Instead, the code is placed in a separate, binary-only, kernel driver. While this provides adequate protection, it does tie the Macrovision support to specific kernels. Hopefully we can resolve that in the future by packaging the Macrovision control logic into a user-mode driver (e.g. a daemon running as root, which has access to I/O space).</font>
<br>
<br><font size=2 face="sans-serif">In short, releasing DVD movie playback for Linux was not as simple as it initially seemed. However, with the constant cooperation of all the parties involved, we were able to work through the issues. It excites me when diverse teams work cooperatively together toward the common goal of improving the end-user experience. And I suppose that's what has drawn me to Linux.</font>
<br>
<br><font size=2 face="sans-serif">So, we did it! I hope that our success helps to raise the bar just a little, that in the future DVD movie support on Linux will be commonplace, and that we can say to Windows users, "DVD movie playback -- yeah, we've got that."</font>
<br>
<br><font size=2 face="sans-serif">-- Keith<br>
<br>
Keith Frechette<br>
Linux Development Lead, Mobile Computing Options and Software Development<br>
IBM Research Triangle Park, North Carolina<br>
kfrechet@us.ibm.com / 919-543-3761 / TieLine:441-3761</font>
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