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Thread: Turn 700mb Cds Into 800mb

  1. #1
    An 800 MB video file on a 700 MB CD!

    The idea is certainly fascinating. Despite DVD-R becoming more and more affordable regular CD-Rs are still the storage media of choice for most of us. As you may know, both VCD and SVCD can actually contain 800MB of movie data on a regular 700MB data disc. Why? Error correction is the keyword. Regular computer data CDs contain a lot of error protection, so your data won't get lost if you have some scratches on a CD. But the data on the CD itself has no error correction. If you start swapping bits in an executable file you have on a CD the file will no longer work. On the other hand, VCD and SVCD stream have some built-in protection so an additional protection on the data storage medium is no longer needed, which frees up space otherwise used for error correction. Those of you who have had a closer look at their burning program may have noticed that (S)VCDs are burned in mode2 whereas regular data CDs are burned in mode1.

    Many people have tried to burn AVIs in mode2 mode only to fail. The burning programs are smart enough to realize that this isn't a good idea. AVI, WAV and most fileformats in general do not have error correction or even only error detection mechanisms. So if the support media does not offer this protection then once there is an error your files are lost forever. Clearly not a very thing, especially since errors tend to become more frequent as time goes by, so while your files may work just fine for the first couple of months, the day you want to print a very important document that you stored on a mode2 CD again, you can no longer read it.

    New multimedia containers like ogm or mcf already offer (or will offer in the case of mfc which is still in development) error correction so an additional level of protection is no longer needed. So let's burn our ogms as mode2 then..

    WAIT! There's a catch and you should not use whatever is written in this document later on without having read this passage: The tools presented here are for test purposes only. While formats like ogm offer some error resilience there's still an additional level of protection needed. A player needs to know what files it is dealing with. This info is usually stored at the beginning or the end of a file. If you have an unrecoverable error in the middle of the movie you may see a couple of blocks which may annoy you a little but you can still use the disc. However, if the same error occurs in the part of the file where the info needed by the player is stored the file becomes unusable. So this info would have to be stored in a mode1 part of the disc and that's currently not possible. Mode2 also doesn't allow you to have exact filesizes so files are being padded to span a known number of sectors but the real size would have to be stored somewhere and that's currently not implemented. Last but not least for compatibility reasons the mode2 files will have an 8.3 naming convention so if a filename is longer the full name has to be stored somewhere. Obviously, eventually these problems are all going to be resolved but for the time being bear them in mind. Do not use mode2 CDs to store any data that you cannot afford to lose.

    It all started with a thread about putting 800MB AVIs on a 700MB CD in my forum and in time we got what's now known as Mode2 CD Maker, by DeXT. As you can see the tool was originally designed to create MFC CDs but it has evolved since. The name MFC-CD seemed to be too closely associated with the MCF format so there was a poll in my forum and the name XCD was eventually chosen. Mode 2 CD Maker can create a mode2 image file that you can burn using any .cue/.bin capable burning program. Initially burning these images wasn't of much use as you had to use another program to extract the files again. Avih came up with a filter that allows you to read these files directly off the disc. You may recall the news about this filter, initially it read the whole file into memory and you had to use one filter for every type of media but all these problems have been solved since. There's just one remaining issue.. not all drives seems to be compatible to the filter. Some DVD-ROMs may refuse to play such files, but usually updating the firmware can fix this problem. I tested it on a Pioneer 16x DVD-ROM and had no problems whatsoever.

    Currently XCD is still under heavy developments, the tools I'm going to present are just a starting point and I expect to see much more in the future. Oh, btw, XCD is an open source project hosted on sourceforge. If you're a developer and interested in joining don't hesitate. The current specs can also be found on the XCD homepage
    More Info & Download

  2. Software & Hardware   -   #2
    100%'s Avatar ╚════╩═╬════╝
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    Do not use mode2 CDs to store any data that you cannot afford to lose.
    Thanks for info - have you tried it?

  3. Software & Hardware   -   #3
    Nope, i'm using 800mb cd's.

  4. Software & Hardware   -   #4
    masterpiece21's Avatar 5C 12.24.42
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    They have some info on this at www.doom9.org

  5. Software & Hardware   -   #5
    thanks man just wat i needed

    cus i always watse 2cds on 1 move

  6. Software & Hardware   -   #6
    muchspl2
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    Originally posted by xxxSHARExxx@21 April 2004 - 15:25
    thanks man just wat i needed

    cus i always watse 2cds on 1 move
    why
    just about all movies will fit on 1 cd

  7. Software & Hardware   -   #7
    You mean divx?

  8. Software & Hardware   -   #8
    Robert00000's Avatar Interweb Fantasist BT Rep: +1
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    Originally posted by killer04@21 April 2004 - 21:12
    You mean divx?
    no he means kvcd

    EDIT: I've been thinking of getting a divx player, but don't have much time to watch movies anymore
    Robert00000

  9. Software & Hardware   -   #9
    muchspl2
    Guest
    well both really
    I have never downloaded a divx/xvid movie that didn't fit on one cd without editing, unless it was a 2 cd rip (let me explain)
    you should never have to edit/split a movie to fit on a cdr, kvcd requires alittle time to re-encode but thats different
    just do a search for video splitters, I don't even look at them any more because I don't want to explain that they don't have to, and if I copy paste instruction on how to turn over burn on again, well I will just have to burn this place down

  10. Software & Hardware   -   #10
    Originally posted by Zedaxax@21 April 2004 - 19:41
    Do not use mode2 CDs to store any data that you cannot afford to lose.
    Thanks for info - have you tried it?
    I've used this many times using the Mode2 CD Maker GUI to burn those 730MB DivXs. I've never had any problems with it, you just have to install the special XA filters on any computer that you want to read the mode 2 cds. I've used this for about a year, and have a whole stack of XA burned cds.

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