topolinik Posted December 12, 2006 Share Posted December 12, 2006 I see Imgburn lists a lot of details about the disc i put into the drive, the supported speeds, the manufacturer infos and so on. Some of them are quite interesting but i can't understand. About any dvd it always says "First Physical Sector of Data Area: 196.608" what does this mean? Does it leave 384 Mbytes empty on the disc (196608x2048)? What's the difference between the parallel track path (PTP) and the opposite track path (OTP)? What do they mean in detail? Why in double layered media the number of the "last physical sector of data area" if always huge? it's always up to 16.000.000 and even more: a (double layer) dvd can't contain such a huge amount of sectors (16000000x2048 would be around 30 Gbytes)!!! How does the count work? Thank you topolinik Link to comment Share on other sites More sharing options...
blutach Posted December 12, 2006 Share Posted December 12, 2006 Re the 196,608. The DVD format specification put out by the ECMA requires this be left free for system stuff like the burst cutting area, the power calibration area, the recording management area and the leadin. After all that crap, the user data recording area can finally begin. This is the only user accessible area on the DVD. So the first phyiscal sector of the data area starts at physical address 196,608, OK? OTP/PTP means the way the way laser changes direction in a dual layer DVD. OTP = start from hub on layer 0, go to outer edge and then go back towards the middle on layer 1. PTP starts from the hub on both layers. ALL DVD-Video is OTP (except single layer disks, which are redundantly coded PTP). Dunno what kinda DVD blanks you got, but all of my single layer DVD+Rs have last sector of data area = 2,491,711. Taking away the 196,607 sectors left for system crap leaves 2,295,104 = the size of a DVD+R = the free sectors reported by ImgBurn (multiply by 2048 to get free space). If you are really interested in all this guff, check out chapters 10, 24 and 25 of ECMA 279 - http://www.ecma-international.org/publicat...ST/Ecma-279.pdf Hope this helps. Regards Link to comment Share on other sites More sharing options...
topolinik Posted December 12, 2006 Author Share Posted December 12, 2006 Well, the "last physical sector of data area" question was not about blank dvds but about original MOVIES dual layer dvd bough in shops (the hollywood creations, i mean). I took a look at them also :-) Thank you for your quick answer, i'm going to download the ecma paper! topolinik Link to comment Share on other sites More sharing options...
blutach Posted December 13, 2006 Share Posted December 13, 2006 If you read it all, we probably won't see you back for a year!! It's pretty boring guff Yes, I can see what you mean about the ID for DVD originals. Puzzled by that one. However, the sectors and reported size are correct. Regards Link to comment Share on other sites More sharing options...
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