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List:       linux-video
Subject:    DVD/MPEG playback device
From:       Christian Wolff <scarabaeus () ccc ! de>
Date:       1999-06-29 10:22:10

Hello.

Since there were some questions about outputting DVD video, i would 
like to get a few suggestions. I'm writing a MPEG2/DVD-driver for a 
decoder/video out card. The V4L-Project so far is basically about 
video in devices, right? Are there plans to support video out, too? 
Or, do you want to rename it to VideoIn4Linux? ;-)

The easiest way to playback MPEG streams with this driver is to just 
'cat' the stream into the character device. It takes MPEG1 system 
streams, MPEG2 program and transport streams, and split streams of 
MPEG ES and PES. For the latter, 2 streams have to be put into 2 
devices with different minor numbers. For DVD playback, there will 
be a special front end program that handles the neccessary ioctl's. 
I already got a major device number (162) for this project from H. 
Peter Anvin

So, how can i implement this in accordance to the V4L-project? 
Issues are:

- What would be a good name for the device? Right now i am using 
/dev/msc, for Media Stream Consumer, but that name is not very sexy.
/dev/mpeg would work, but i guess there are coyright issues ;-)

- What distance should i use between the 2 minor numbers for one 
card; 16, 32, 64, or 128? This would affect the amount of installable 
cards in a system, and extensibilty of the driver (in case more than 
2 streams are needed in the future). Right now i'm using 16, eg. i 
would cat the Audio ES into /dev/msc0 and the Video ES into /dev/msc16.

- I am using several ioctl's for setting the video standard, setting 
stream parameters, and using special fatures of the card, such as 
on-screen-display. What range of numbers should i use to not collide 
with other ioctl's?

I could also extend the driver to take sequences of YUV-pictures, 
if that would be useful for anyone. This would probably not work 
in realtime.

  Thanks a lot,
    Christian Wolff.


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List:       linux-video
Subject:    Re: DVD/MPEG playback device
From:       Eric Jorgensen <alhaz () xmission ! com>
Date:       1999-06-29 12:16:59

Christian Wolff wrote:
> 
> Hello.
> 
> Since there were some questions about outputting DVD video, i would
> like to get a few suggestions. I'm writing a MPEG2/DVD-driver for a
> decoder/video out card. The V4L-Project so far is basically about
> video in devices, right? Are there plans to support video out, too?
> Or, do you want to rename it to VideoIn4Linux? ;-)


	There are fundamental issues to be overcome before we can acccomplish
DVD under Linux. 

	First, and possibly most importantly, DVD video streams are encrypted.
The encryption technology is far from open. Almost all PC DVD devices
rely on decryption occuring in software. DVD under Linux would require a
closed-source, non-free ($$) decryption system (could probably be done
as a shared library), or a DVD decoder board that performs the
decryption in hardware. 

	There is a company that has designed and built a working prototype DVD
decoder with hardware decryption intended for Linux systems, they are
currently seeking investors, since they don't have enough money to put
the boad into production. I'm sorry to say I don't have their url handy. 

 - Eric


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List:       linux-video
Subject:    Re: DVD/MPEG playback device
From:       Christian Wolff < scarabaeus () ccc ! de>
Date:       1999-06-29 13:55:22

Eric Jorgensen wrote:
> There are fundamental issues to be overcome before we can acccomplish
> DVD under Linux.
> First, and possibly most importantly, DVD video streams are encrypted.
> The encryption technology is far from open. Almost all PC DVD devices
> rely on decryption occuring in software. DVD under Linux would require a
> closed-source, non-free ($$) decryption system (could probably be done
> as a shared library), or a DVD decoder board that performs the
> decryption in hardware.

The driver i'm writing is relying on the CSS built into the card 
i'm using. ;-) All i have to do is handing the challenges and 
responses between the DVD-Drive and the Card. There is already 
a new set of DVDROM-ioctl's for this purpose from Andrew Veliath 
( http://www.rpi.edu/~veliaa/linux-dvd/ )

> There is a company that has designed and built a working prototype DVD
> decoder with hardware decryption intended for Linux systems, they are
> currently seeking investors, since they don't have enough money to put
> the boad into production. I'm sorry to say I don't have their url handy.

Actually, that's exactly the company i'm writing the driver for. 8-)

  ciao,
    Christian Wolff.


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List:       linux-video
Subject:    Re: DVD/MPEG playback device
From:       "matthew.r.pavlovich.1" <mpav () purdue ! edu>
Date:       1999-06-29 14:59:16

> 	First, and possibly most importantly, DVD video streams are encrypted.
> The encryption technology is far from open. Almost all PC DVD devices
> rely on decryption occuring in software. DVD under Linux would require a
> closed-source, non-free ($$) decryption system (could probably be done
> as a shared library), or a DVD decoder board that performs the
> decryption in hardware. 

There are actually non encrypted DVD's out there, just not that many.  I
have been talking to a few other developers working on DVD and we want to
find a company that can foot the bill for the license and then release a
free binary only library to handle CSS auth. 

> 
> 	There is a company that has designed and built a working prototype DVD
> decoder with hardware decryption intended for Linux systems, they are
> currently seeking investors, since they don't have enough money to put
> the boad into production. I'm sorry to say I don't have their url handy. 

Hardware decoding is great for the data streams, but there is still an
unlocking mechanism on the drive itself, which needs to be addressed.
Again, this is where a library could come in.\

-Matt


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