Slashdot Mirror
DVD-RAM Support
Nathan Laredo (the A/V guru from the expo who had 4 MPEG decoders in his machine
running simultaneously) wrote in to say that he's "hacked out" full
read/write/rewrite functionality for the Panasonic LF-D100 series of
Panasonic DVD-RAM drives under Linux, and the diff is available at OPN.
He says he's used the driver to copy three unencrypted DVDs, and that you probably don't want
to use ext2 on the drive (though it can be done "painfully").
Neither. He used non-encrypted DVDs.
You missed the fact, that DVD-RAM can only be read by DVD-Players explicitely supporting DVD-RAM. Most, if not all, standalone players and DVD-ROM drives for PCs out there are unable to read DVD-RAM!
Same goes for DVD+RW.
There are many things about supporting Linux, and about supporting Open Source in general, that make good business sense. The fact remains that most companies don't understand that yet, so it's good news when one does. This kind of behavior should be encouraged (but I'm not sure that mailbombing one guy with hundreds of thank-yous is necessarily the best way...)
I've also heard that Sigma Designs will be doing Linux drivers for their next generation of decoder card; they can't do it for the H+ because the H+ actually does its decoding in on-card software.
This doesn't make sense. If the hardware does the decoding itself, it should be EASY to write an interface, not harder.
yep!
http://linuxtv.org
I don't know why this guy gets credit since Nagai Hidetoshi posted his DVD-RAM patch for kernel 2.0.33 in May 1988 and his does more (granted it's not a straight patch onto the 2.2.x kernels).
Why is DVD-RAM different? Well, it looks and acts like a CD/DVD-ROM drive, but it's writable. Without special support, the OS just thinks it's a CD-ROM drive (read only). This is different from optical or hard drives that have a different SCSI type IDs.
If I remember correctly, since Linux doesn't create devices for partitions for CD-ROM drives, there's a problem just marking the CD-ROM drive as writable. You can't recognize any partitions! Mr. Hidetoshi's patch actually spoofs the SCSI driver to think there are two devices... an optical drive and a CD-ROM drive. Thus you can use it with partitions as an optical drive, but you can still use it as a CD/DVD-ROM drive. This is basically what the Software Architect's DVD-RAM driver software for Windows and MacOS does.
This guy's patch appears to just mark it as a removable hard drive, thus it won't be recognized as a CD-ROM drive anymore. I assume that's okay for most people.
I think the problem is that the CSS decryption is done in software. The rest is done in hardware. I know the dxr2 does CSS in hardware, which is why I really don't understand the legal issues.
-matt
Why can't someone just get a license for CSS, sign the NDA, and release a closed source libcss that will allow CSS decryption? If an individual can't do this, i think it would be a good way for creative to gain a great deal of respect. Then again, i doubt it would take that much work to reverse engineer / abuse this type of system. The whole copy protection thing is dumb anyway, serious bootleggers will get around it, in the end it only hurts the consumers, and to a lesser extent the industry itself. How many of you slashdot folks would own a dvd-rom right now if you could watch dvds under linux?
-matt
I was planning to buy a CDR drive. Does this news have any bearing on my decision? I know that a DVD-RAM hold a whole lot more, but can it write CDs that mere mortals can read in their old CD-ROM drives?
In addition, though a driver exists (all three lines of it?), how reliable is the whole shebang? Will I, assuming I go and buy this drive tomorrow, be able to produce real and productive results?
Thanks for the help.
-awc
Yeah, but the point is, you don't NEED real-time mastering, if your source is on the computer! You process one block of data, dump to a specific point on the disk, and get the next block. It's not like recording off TV, where you've continuous data.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
With all the talk about being able to play back DVD's under linux, I was wondering why nobody has created a standard MPG player that uses hardware acceleration. I have many video cd's, but since all of the linux MPG decoder programs (such as MTV) only do software decoding playing the movie in double size skips horribly, and full screen is unwatchable (this is on a PII 400 with 128 Meg RAM). Is there some reason why Linux MPG decoder programs don't use the hardware on my video cards like Windows programs do? I hate booting into windows just to watch a Video CD...
The data on the dvd is scrambled. I don't know for a fact, but what i'm assuming they do is encode all of the data, including the all that low-level stuff like ECC. That way when the dvd-rom tries to read the data it gets an error. This will prevent you from copying that data on to your hard drive, but will not prevent a serious bootlegger from accessing the data.
I really can't imagine that the system is 100% secure. Which kinda makes me wonder, when you buy a dvd you aren't agreeing to any licensing terms, right? So if you bought a dvd and were able to say, read the encoded mpeg header from a secure file on the disc and figured out what would need to be done to translate it to the unencoded version, that would be legal. Too bad I have no idea how to go about doing this.
-matt
The poster who asked who to thank at Panasonic has a good point!
This (hopefully) is a good way to both foster goodwill by saying "Thanks, guys, we appreciate the gift!" and to let them know how many people would like to use a DVD (/RAM) drive with a Free OS.
I bet they don't get a lot of "thank you"s when they release a new driver for the Windows family of OSes, in part because most users view it as a default, just an integral part of their machine. Sort of like those who are not into automobiles (I'm not) don't care so much about some new engine part.
But those who appreciate the fact that a lot of uncredited hours go into every free / Free program can be more appreciative. It would be great to let Panasonic know they've pleased a lot of people by contributing one of their drives and more important the documentation for it.
So if anyone from Panasonic is reading this, WOOHOO! Thanks!
And again, if we know where to direct better thank yous, I'm sure people will send some.
timothy
jrnl: http://tinyurl.com/c2l8yr / foes: http://tinyurl.com/ckjno5
The format for DVD is publically available from ECMA (www.ecma.ch) at ftp://ftp.ecma.ch/ecma-st/e267-pdf.pdf. The Content Scramble System (CSS) used to encode DVD-Video is licensed to individual companies, and not likely to be open source in our lifetimes if the CSS Interim License Org can help it.
I NF-8090.PDF
Another useful reference is the ATAPI (AT Attachment Packet Interface)for ROM, RAM and R/W DVD at ftp://fission.dt.wdc.com/pub/standards/SFF/specs/
CSS needs about 3 sub licenses at 1000000 Yen each and a very very strict NDA.
I'm confused, I thought RAM stood for random access memory where all accesses to the hardware happen at the exact same speed.
:)
For instance, with RAM you can read the first byte of RAM and then read the last byte of RAM at the same speed as if you were to read the second byte of RAM.
I never quite understood how RAM got the additional meaning of being read-write but still maintain it's acronym as random access memory.
This is why I push for DVD-RW, which has a sane name
--
The world is neither black nor white nor good nor evil, only many shades of CowboyNeal.
So, is it tru that there's no HW support for a DVD MPEG 2 playback card yet?
How, then, can software decoders work with the encryption system that's on DVDs?
Finally, is there any way to play an unencrypted MPEG 2 video stream on Linux? HW or SW?
Under this definition, DRAM is not RAM since DRAM cannot be accessed randomly at the same speed
;-)
as linearly (linear is much faster, random access requires row precharge time).
I think you'd better update your definition, or maybe not tend to trust FOLDOC... or maybe
we all need to concede that 640K of ram (being larger than most caches) hasn't even made it
to the mainstream yet... or maybe not
Where can you get a Canon XL1 for $1500?! Do tell! I can still go into credit card debt before I die ...
... firewire, even USB, are way faster, and as long as both camera and computer are using these interfaces intelligently, you'll get much faster throughput.
BTW, I've often heard video transfer from a digital camera referred to as capturing, even though this is a slightly different use of the word than was accepted a few years ago. Even if it's really only a data transfer rather than a true "capture," the use is analogous, since you are pulling video into your computer.
And even if you're not capturing in the old sense, I don't see how a serial port would be nearly as good as a firewire port
Just thoughts,
timothy
jrnl: http://tinyurl.com/c2l8yr / foes: http://tinyurl.com/ckjno5
your question is very ambigious, and a bit un informed. Usualy a Capture card is reserved for captureing analog data, and requires alot of expensive hardware if you are lookling for fullscreen 30FPS full color stuff. we are talking RAID and several thousand dollat cards. DV cams are well, digital. Why pay 1500 bucks for a Cannon XL1 and plug it into a ATI all-wonder and effectivly make your expensive DAT based video camera on the same level as a 150 dollar handy cam. You do however have a couple of options 1) most(if not all) consumer DV camcorders have analog out. you could just plug this into a standard capture card and go. this sucks AD->DA->AD->DA by the time you pay the video on your computer. I will assume this is not what you were asking. 2) Some brands have propritary cards that you plug in your machine and it pulls across the digital info. 3) firewire. you plug your camcorder into a firewire post on your computer and pull across the informtion that way. For all it matters, they could do it over serial or USB as well, its just I/O and because your not capturing, high speed is not required(just lots and lots and lots of space ;->)
Your turn for free clues. DVD-RAM has 5.2 GB per platter; 2.6 GB per side. OK, you win, that's "one plus" gigs.
Joe, the problem is that DVD-RAM drives are schizo. They advertise themselves to the SCSI bus as the same class as CD-ROM, which is why no special driver is needed to read CD-ROMs in them -- this is what makes them different from Zip drives, etc., which advertise themselves to the SCSI bus as removable media drives.
So while DVD-RAM is not a CDR type thing, it suffers from the same shortcoming: without special drivers, both can serve only as CD-ROM drives.
It would be nice if the DVD-RAM drive had a jumper to change the device type advertisement to the SCSI bus from CD-ROM class to rewriteable-optical type -- then it would be recognized by Linux and everything else as a magneto-optical drive. It wouldn't work as a CD-ROM or DVD-ROM or DVD video drive when so jumpered, but DVD-ROM drives are cheap anyway. I'd just add one. It would be cheap.
Loligo: a clarification and a caveat:
Clarification: the cartridge can of course be removed from the drive just fine; it's just that the disk proper cannot be removed from the cartridge without destroying the cartridge, and you would be left with two very delicate optical surfaces if you did so. It is very likely you would quickly degrade the data integrity of the disk by handling and storing it without the cartridge, but theoretically, if you were very, very careful, everything would work just fine recording and playing back without the cartridge. There is certainly nothing magic about the cartridge. It is a simple protective device with a shutter, much like that of a 3.5" floppy, a Zip disk, or a magneto-optical disk. It's just that, while it's virtually impossible to conceive trying to use a 3.5" floppy, a Zip, or M-O disk without the cartridge, you can easily imagine experimenting with using a DVD-RAM disk without the cartridge.
Caveat: the type 2 disks can only be read in DVD-ROM drives specifically designed to read them. I am not aware of any specific DVD-ROM models yet that can read them, but it's not unlikely there might be one or two brand new models which can do so.
The type 2 require extremely careful handling too, when not in their cartridge. It's just that only one side is delicate, so it's not as bad as trying to do it with type 2 disks as it is with type 1 disks.
Hmmm. Makes you wish someone would leak the information. I wonder if they do anything to the documentation for each person to identify where leaked copies come from.
What would the legalities be if a driver was written that used information that was leaked from NDA. What if there was no proof that it was from that leak, if they could concievably have reverse-engineered it.
Encryption stuff like this sucks. If DVDs weren't encrypted, we could use them on more OSes, hack together players, etc.
Hasn't this been available for a long time?
BitWizard has had a patch on their page for a long time and it supports drives from several different manufacturers, too!
What is new about Nathan's patch that isn't provided by the BitWizard patch?
Did I mention that I can also PLAY unencrypted dvds
under linux? This was how i tested the copies.
I've also been working on a hardware mpeg2 decoder
driver for linux (it's been done since April).
whats the pricing of the drive and media for it?
This is the last thing that I wanted before switching my computer over entirly to linux. Haraw! Install fest tonight. (three machines, heck i'll do the other two while I am at it)
Do you changes clothes while making the "chee-chee-cha-cha-choh" transformation sound?
This is a bit off-topic, but has anyone heard of drivers for DV capture cards? ie so you can get video digitally off your DV camcorder or whatever. I was looking the other day and didn't find anything at the time...
Please, DVD RAM doesn't even know if it's going to stay around... I would assume so. Prices are still high and the 2 big boys are still fighting over who's format to use.
I'd just like to WATCH a DVD in linux let alone write to one. I STILL have to boot to Win (ugh) to watch a DVD with my SBLive.
Damn I wish I could code better, at least I can beta damn well...
If you lika me like I lika you...
It's going to make efforts such as the Free Film Project much more exciting, now that it's practical to create a DVD. Streaming video is nice, but very low-res, painfully small and subject to how busy the network is. The potential to create a home-playable disk that's accessable to anyone with a player opens up a lot more possibilities.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Is there any work being done on consumer level support for DVD-ROM? A Toshiba DVD-ROM and MPEG decoder card came with my laptop and I'd prefer not having to reboot into Windows to use the DVD features of my drive. Thanks in advance for any information.
This article is rather confused (Or maybe it's just me.) Are you saying we now have DVD support under Linux, for at least that one player? If so, I guess I'll have to add a DVD drive to the list of things to get during my next upgrade cycle. Will it play all DVD's or am I going to have to be careful which ones I buy?
Does this meant that it can copy an .mpg on a DVD video disk to a hard drive? I'm assuming not, but the wording on the post was pretty unclear. How is DVD video encryption done?
David E. Weekly (dew, Think)
David E. Weekly
Code / Think / Teach / Learn
h4x0r for
Again, I have no other information or facts to present, that's just what I was told by two different tech support guys.
I don't suppose you realize these are two different standards with similar names...
DVD-R : write-once version of DVD-ROM...
DVD-RAM : low capacity, older format
DVD+RW : HP/Philips/Sony (most similar to DVD-ROM)
DVD-RW : Pioneer (fading fast)
These days, all bets seem to be leaning to DVD+RW... (probably because '+' is better than '-')
Can someone explain why a SCSI DVD drive would need special drivers? Shouldn't a SCSI device generally work right out of the box? I've plugged in removeable media SCSI devices before without needing any special drivers (ZIP drive, an old Floptical drive). Is this actually code to deal with whatever file system DVDs use, and not something truly specific to DVDs, or is there really something special about DVDs as opposed to regular SCSI devices?
If we were talking about an IDE DVD instead, how much different would things be? I've never run across IDE devices other than hard drives and CD-ROM, so I don't know from personal experience if it is as easy to deal with random devices as it is with SCSI (or so I thought).
Posted by Ungrounded Lightning Rod:
Depends on how they did it. If they built in some firmware that assumes an underlying Windows or NT platform and uses hooks it finds there, it might not be compatable with Linux, and might require the driver to upload a replacement version of the firmware, or even a ROM change.
Posted by Ungrounded Lightning Rod:
I think it would be a SCREAM if this version of DVD became the dominant one just BECAUSE:
- they gave a Linux hack a free drive and internals info, and
- this resulted in their drive being the first one usable on Linux, and
- THAT resulted in a bunch of extra sales and
- their drive then became the defacto standard.
B-)
Posted by Ungrounded Lightning Rod:
Once it's captured, crunch it up at less than real time and/or throw a bunch of CPUs at it.
What's a Beowulf cluster FOR, anyhow? B-)
nexthec, read Chris Rijk's question again. He asked about the availability of [Linux] drivers for DV capture cards. DV cards already have Windows drivers, of course.
Chris' question is perfectly reasonable and not even slightly ambiguous (note the spelling) or uninformed. A capture card can capture either analog or digital data. A DV capture card obviously captures digital video data. It is also possible to get a DV and analog capture card which captures both analog and digital video data which is what most people who buy DV-only capture cards later realize would be more useful because they would get backward compatibility with (S)VHS and real-time conversion-to-DV for their old collections of (S)VHS tapes. A good example is the Fast DVMaster card which has 2 DV inputs and 1 DV output, analog SVHS input and output with NTSC and PAL support. The card has no Linux drivers available yet but customer pressure could change this. Send requests for Linux drivers to Anuschka.Schweizer@fastmultimedia.de who is the product manager for the DVMaster.
Has anyone actually looked at the patch? All it does is a strcmp for the drive in question and marks it as ejectable. From the looks of it, this drive would probably work without applying the patch at all. It would just be lacking a software eject function.
I've been running a creative labs DVD-RAM drive as floppical device for some time. Formating it ext2 hasn't been a problem.
UDF on the other has been quite a bit of trouble. You have to create a UDF image on your hard drive, and then write it to the DVD-RAM. I don't have that much free space lying about. Never mind convince cdwrite to write to the drive. In addition UDF write support is rather buggy. Although I've had good luck with reading UDF formated disks.
Now if only I could get my hands on some single sided media so I can transfer things around to machines with DVD-ROM drives.
IANALBIPOOGL (I am not a Lawyer, but I play one on GrokLaw.)
Found the link that explains why you can't record video DVDs yet. It can explain things better than I can. Check it.
Editor Emeritus and Senior Writer, TeleRead.org
that's what I do to get full screen VCD playback. /etc/XF86Config already)
(you probably have a modeline for it in your
my next hack - make my voodoo3 do tv out in linux at 320x240!
ummm hey big guy the "RAM" part of "DVD-RAM" stands for Random Access Memory. Yup that makes it a *writable* DVD drive. Even a lowly sysadmin like myself knows you'll need someone to hack the drivers to get the burn part of the system to work. One plus gigs on a platter to start with and then we should get more in a year or two...
use Signature::Witty;
other than that, I have no idea.
The Panasonic drive -- like the other DVD-RAM drives out there -- use these "cartridges" for the media.
Are these like the "caddies" used for high-reliability CD drives, in that the media can work just fine without the "cartridge" in a regular DVD player or DVD-ROM drive, or are the two inseparable?
What if we started a campaign to encourage independent film makers and regular people making copies of thier own movies, to use a different standard of encoding, while still using the DVD disc size. Of course we would have to use the basic MPEG movie encoding, but the encryption could be something else, something open but secure against piracy. Is there anything like that out there? Would such a campain be possible. I think if we could develop such a system and convense that movie industry that our system is not only cheaper (free???) but just as secure they might move to such a format themselves? And everybody could use them. Is such a thing possible. Any comments suggestions ideas? The MP3 campaign is going strong, but I believe we could take on another, though this one may be even more difficult.
DVD-RAM V2.0 has a capacity of 4.7GB / side. But it is only announced and not yet shipping. JUST LIKE DVD+RW AND DVD-RW ARE NOT YET SHIPPING.
As for DVD+RW being most like DVD-ROM, that is just marketing hype. DVD-R is the most like DVD-ROM (most of the players we tested it on could read it.) DVD-RW is the next most like DVD-ROM many players should be able to play it. As for DVD+RW and DVD-RAM there are currently NO players on the market that can read these discs.
I would say that the bets are going the other way especially for data applications.
All I have to say is, so? They gave him $200 worth of equipment, which is like, nothing to them. And in return, they get to say their drive is supported under Linux, which will get them many sales and possibly even a tremendous 'first mover' advantage as their drive gets mentioned in DVD-HOWTO's and the equivalent for the rest of eternity. Well worth the investment.
And that's not too far fetched, considering they WANT you to return the board to them to reset the region lock if you exceed the max # of changes (5)
The format in which DVDs are written is under a strict NDA. So strict that even companies that license it must pay for *each person* that is going to look at the format specifications.
Does this mean that Nathan has reverse engineered the format? Or does he actually have a license to the format specifications?
You should never take life too seriously - You'll never get out of it alive.