Many DVDs disable navigation to the main menu during previews, copyright warning, etc.
This DVD player uses a collection of heuristics to attempt to do the right thing when you press "main menu", even if the DVD does not present this option. For example, it might remember where on the DVD the main menu was, the last time this DVD was played. Or, the first time a DVD is played, it might analyze the shape of the links between parts of the DVD in an attempt to guess where this menu is.
Summary: you are never stuck watching 5 minutes of crap before the main feature.-- regehr, Sep 08 2007 DVD region code hacks http://www.videohelp.com/dvdhacksWhile we're on the subject of breaking idiotic restrictions, here's a handy list of hackable players and how to disable their region restrictions. [jutta, Sep 08 2007] AnyDVD http://www.slysoft.com/en/anydvd.html [kinemojo, Sep 09 2007] That's the DVD's fault for not including the option? I always figured that this was a deliberate agreement between the DVD producers and the player producers that allows the DVD producers to explicitly disable navigation for certain sections they absolutely want people to watch.-- jutta, Sep 08 2007 I could be wrong, but we use our PS2 to watch DVDs and I can always skip the previews...at least I think I do.-- xandram, Sep 08 2007 What features are available at what point in the DVD is a function of the DVD. It has to define what the "Go to Menu" button does, and if it has not done so yet, there is nothing the player can do. Same with the scene skip. Scenes have nothing to do with the physical structure of the tracks on the DVD, just with the organization of the data.
Basically what you would need is a player that reads far enough into the DVD to discover what "Go to Menu" is going to do at some point, then make that available. A fast DVD reader could do that, then just basically create a virtual copy of the DVD in memory. Then it could play from the image making assumptions about what undefined buttons are going to do at some point in the future. (Man, I hope that doesn't sound like Treon.)
Basically a DVD is a computer program with imbedded data. The first item in the program/on the disk is a video with a set of exits defining what happens if input is recieved from the remote control. At the end of that video there is an instruction to either replay that same video, or play a different video. This then repeats.
So on a typical commerical DVD, the first video on the disk is the government warning, there are NO exits during this play that accept input from the remote control. At the end of that video is an instruction to start the first preview.
The first preview probably has exits defining what the fast forward key does, but none defining what the menu key does. There might be an exit that reads the skip scene button and sends you to the next video in sequence.
At the end of the last preview there will be an instruction to go to the menu video. The menu is a short video that shows you the buttons on the menu, possibly flashing or something, while playing music and stuff. At the end of that video is an instruction to start the same video (the menu) over from the beginning. During this video there is also some fancyness that marks buttons for you and allows you to move a marker between those buttons. Exits allow you to start the feature. At the end of the feature is an instruction to return to the menu.
Pretty elegant little structure actually.-- Galbinus_Caeli, Sep 08 2007 Galbinus said "What features are available at what point in the DVD is a function of the DVD. It has to define what the "Go to Menu" button does, and if it has not done so yet, there is nothing the player can do. "
Ah but of course the player is free to seek to whatever part of the DVD it wants to -- that is what my idea was trying to say. If the player had good heuristics for figuring out where to go, it could go to menu even when the DVD does not provide this option.
Jutta said: "That's the DVD's fault for not including the option? I always figured that this was a deliberate agreement between the DVD producers and the player producers that allows the DVD producers to explicitly disable navigation for certain sections they absolutely want people to watch."
Sometimes the player manufacturer's interests align with the content providers' interests and sometimes they align with the consumers' interests. Case in point: I bought a player made by Philips -- a company that (as far as I know) does not provide content. Making this player permanently region free was a matter of pressing three buttons on the remote! I figure they don't want to ship a region free player, but in order to increase sales they make it really easy for consumers to make it region-free on their own. Try that on a player made by Sony...
Anyway, if there are legal problems with a player that skips previews, this feature could perhaps be enabled by a "secret" key sequence on the remote just like the region free feature on my player.-- regehr, Sep 08 2007 Just to be clear - I don't think there's a legal problem, although there may be a pissed-off rich consortium problem. (In bad cases, those eventually grow into legal problems; e.g. DMCA.) For region coding, the legal problems run in the consumer's favor - some countries don't think region coding is legal, and it may be their resistance to this manipulation that made the circumvention codes as common as they are.-- jutta, Sep 08 2007 [regehr] I don't think you quite understood me. Unless and until the program on the DVD defines what the menu is, the player has no way of knowing where to skip to. In fact a DVD does not even have to have a menu to be valid, nor does it have to define only one menu. It does not have to accept ANY user input, it can be one MPG video file with no options for the user to do anything but sit there.
Your magic DVD player would have to read through the contents of the DVD until found a menu. And since most DVD players use single speed drives, that is going to take just as long as sitting through the warnings and advertisements.-- Galbinus_Caeli, Sep 09 2007 Galbinus said "I don't think you quite understood me. Unless and until the program on the DVD defines what the menu is, the player has no way of knowing where to skip to."
Right -- so here is the heuristic. The first time you play a disc, the player cannot skip to the menu, but as you use the disc it remembers the location pointed to by the menu button. If there are several menus, it picks one using some reasonable heuristic. If there are zero menus, then this feature will not work.
Then the player stores this in nonvolatile memory where it can be used when you next play the same DVD. Or, optionally, the DVD player could consult a CDDB-like Internet database containing menu locations for lots of discs. This information should be reliable since presumably it would be vetted by a human prior to uploading.-- regehr, Sep 09 2007 Galbinus said "But it will not work if you drop a disc in that the player has no knowledge of (and cannot look up)."
Yeah, and as you say scanning the whole disc is going to be slower than just sitting through the previews.
On the other hand, perhaps there are shortcuts that can be taken even for a totally unknown disc. That is, use the hierarchical filesystem rather than doing some sort of linear scan.
For example, I just poked around the filesystem on a DVD and there's a toplevel directory VIDEO_TS containing a bunch of video files. It is not a big stretch to imagine that the four largest VOB files in this directory (1 GB each) correspond to the four episodes of "Lost" that I know are on this disc.
So perhaps all we really need is a button on the DVD remote, successive presses of which play the VOB files on the DVD from largest to smallest. Most times the big files will be the ones of interest.-- regehr, Sep 09 2007 widely known to exist-- kinemojo, Sep 09 2007 However it is executed, there is a dire need for something like this. Meanwhile, allow me to suggest a non-software strategy.
Place DVD into player.
Say "Hey, honey, would you like a coffee/wine/beer?" Hand over remote.
Exit room.
Return with coffee/wine/beer. Exchange for remote (most important).
If previews are still playing, go to bathroom, placing remote out of reach of coffee/wine/beer swilling companion - preferably on hall table, bottom stair, WHY.
On my return, the DVD will be waiting patiently at the main menu.
Steps 2 - 5 can be skipped if watching solo.-- egbert, Sep 10 2007 Well I frequently cannot skip or FF through the previews.
Re. the coffee/beer/wine/can solution that certainly works. It's more the principle. I mean I paid for that shit it shouldn't be getting in my way.-- regehr, Sep 10 2007 random, halfbakery