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Pre-play disk check

  (+5, -2)
(+5, -2)
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One of the most annoying things for me is when I'm watching a movie and suddenly it gets a lot of static A-K-A "dropouts" and then freezez in the middle of the movie because the disk was dirty or it was old and worn out/scratched.

I rent movies a lot and it's inevitable that once in a while you'll get a movie that is dirty or broken.

You can of course just wipe the disk clean if it's dirty, but if it's scratched, your movie may never work again except by sending it to be "repaired" (yes, there are in fact services to "repair" DVDs and tapes, believe it or not, but I think that those so called repair services somehow rescue the recording and then copy it onto blank media of the same format and return it, of course most likely charging more than it would cost to just buy a new tape)

So, DVD players should, before playing the movie, do a "high speed check". In other words, roll the disk as usual, but move the laser fast across the disk, "sweeping" a few times, again rather quickly, prefferably taking a minute or less so as not to make it take a "painfully" long time to load. If the player detects any major issues- ideally ones that could cause more than a minute of severe dropout, the player will display an error message explaining that there's something wrong with the disk and it may not play properly, suggest cleaning the disk, and clearly state that if you want to try watching it anyway you can simply press play to, well, play the movie and dismiss this message.

Dickcheney6, Apr 15 2009

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       yeah, something like that. [+]
FlyingToaster, Apr 15 2009
  

       [21Q] does your player ever hang during a section ?
FlyingToaster, Apr 16 2009
  

       nice idea, but i guess it is not possible to check the validity of data without reading it, and reading takes time.
loonquawl, Apr 16 2009
  

       You could just have a cat sit on it.
normzone, Apr 16 2009
  

       "Kinda happens already with some players I've had. It either says "invalid disc," "Disc Corrupted," or "Unable to read." Sorry, I gotta say this is Baked."   

       No-if the player detects larger abnormalities that may cause problems during the actual movie when it's doing the "sweep", the player will say on screen, something like "your player has found some issues with the disk. the movie can be played but may not work properly. you may need to clean the disk. Press play to continue."   

       In other words, if the player can at least "find" the start of the movie, it will then sweep across rapidly with the laser on a few times. Presumably, even though it can't gather any actual video footage, it should be able to detect any scratches or gunk or other damage on the disk as long as the laser is on during this "sweep". If it detects anything, it gives you a warning and suggests cleaning the disk, but gives you the option of watching the movie anyway in case it "mis-reads" something that in fact doesn't hang up the movie totally-just causes some minor (or not so minor) dropouts.   

       the "Unable to read" message you see on current DVD/Blue ray machines happens when the player tries to read, say, the first few minutes of the movie, but it can't find any readable data whatsoever, it will give up and assume that it's a disk that is broken or the wrong format (i.e. a blank disk in a non-recording machine or a recorded but unfinalized disk from another machine, etc.) and show an error message.   

       "you could just have a cat sit on it" Given the nature of my cat, I'd be afraid that she'd chew the wires :D besides, as much as I like cats, I doubt one could do much to make the movie work again. What's she going to do, hiss at it when it stops?
Dickcheney6, Apr 16 2009
  

       It irriates me when the movie stops. I think the DVD player is just being a prima donna. The player needs to suck it up: there is something there, show it, move on. I am reminded of the game Loderunner. One could design one's own levels. However the game would interpret _any_ file as a loderunner level if you told it to, and show the level accordingly. Some of them were very tough to play.
bungston, Apr 17 2009
  

       I agree with bungston- It's annoying how DVD players freeze up from damaged disks. I wish those things would just continue to follow the groove reguardless of whether it can find anything or not, and continue searching ahead for playable footage rather than just falling flat on it's face.   

       Once it has started playing and established tracking, it should be able to follow the groove by simply moving at the same speed as before as though nothing had happened even if it can't "find" the actual signal due to scratches or whatever.   

       That's one of the things I miss about VHS tapes-unless the tape was so badly damaged that it actually snapped or got tangled up in the machine while it was playing, it would continue playing the rest of the movie-even if a portion of the tape was completely erased. Yeah, I know that's a totally different method of recording, but it's such characteristics that gives video tape it's "charm"
Dickcheney6, Apr 18 2009
  

       "nice idea, but i guess it is not possible to check the validity of data without reading it, and reading takes time"   

       But don't CD players do something to this effect (not for checking playability) already? If you put a CD in a cd player but you don't push PLAY right away, it will show the total # of tracks and the approximate running time of the CD. The only way I can imagine it's able to do this is 1. "speed" across the disk with the laser on while 2. searching for "track markers" (what tells the CD player when to change the display digit, or stop when "track skipping") and 3. figure the end time by gauging how far the laser went before no more music was found.   

       with a bit of tweaking a similar process could detect major scratches/smudges on the disk (anything that would cause "epic failure")   

       Speaking of this, I saw a rather amusing sign at my local library "____________ library is not responsible for damage caused to equipment by playing our movies/music" Damage to equipment? How? I suppose if there was peanut butter smeared on the bottom of the disk it could spin off into your VCR and ruin your whole day :D Or, maybe someone thought that scratched could be smoothed out by pounding the disk with something heavy-and they hit it with their VCR! Then they tried to sue the library! Or, someone peed on the disk and then next customer complained that their VCR smelled bad after watching the movie!
Dickcheney6, Apr 03 2010
  
      
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