| Other Useful Information |
When identifying DVD+R/+RW discs 'DVD Identifier' will first attempt to use Method 1. This is the preferred method for ADIP retrieval since it obtains the original ADIP from the disc. However, to retrieve the ADIP in this manner a command is used that may not be supported by some, mostly older, drives. The 'Status'-tab always indicates which method is used and if any errors occurred :
|
DVD+R/+RW Medium Detected. Starting
Identification... DVD+R/+RW Medium Detected. Starting
Identification... |
If your drive does not support method 1 an attempt will be made to retrieve the ADIP by using method 2.While method 1 also works with empty discs, method 2 requires the use of already written discs (either a DVD+R with closed session or a DVD+RW that is at least partially formatted). Every written disc contains a copy of the disc's original ADIP and with method 2 this copy will be read out instead of the original ADIP. Since reading this copy of the ADIP is done by a command which is supported by nearly all drives no significant drive compatibility issues are expected here. Do note that there are in fact some drives that can still handle method 2 even with empty discs.
| DVD+R/+RW Medium Detected. Starting Identification... ** Initiating ADIP Retrieval Method 2 (Copy Of ADIP) ADIP Read Method 2 Completed Without Errors |
Method 2 fails on most drives when an empty disc is used :
| DVD+R/+RW Medium Detected. Starting Identification... ** Initiating ADIP Retrieval Method 2 (Copy Of ADIP) ADIP Read M2 Failed : Illegal request - Invalid field in CDB [05/24/00] ADIP Read Method 2 Requires A Written DVD+R/+RW Disc |
Do take into consideration that the DVD+R/+RW 'Media code'-block may contain drive modified values when the ADIP is read through the use of Method 2 (= Copy of ADIP). This means that the ADIP information shown in the hex dump is not 100% identical to the original ADIP on the disc (Method 1 is required in order to retrieve the original unmodified ADIP). 'DVD Identifier' will still report the correct disc parameters because it will compensate for this problem by using additional techniques to retrieve all the needed information. Following values are likely susceptible for modification by the drive : Book type, Last physical sector of data zone (only for DVD+R, not for DVD+RW) and the Extended information indicators. Basically the entire range starting with byte 0 up to and including byte 18 (=0x12) may contain modified data (shown in red below).
|
** WARNING : Format 11h (Method 1) Is Recommended ADIP Retrieval
Method |
When the 'Media code'-block is retrieved from the disc, the drive will always insert a 4-byte header in front of the 'Media code'-block. Since this header is totally unrelated to the disc and therefore contains no useful information it is by default removed by 'DVD Identifier'. If desired, you can clear the 'Discard 4-Byte header'-checkbox in the 'Advanced'-menu so that the header is included anyway. This option is offered solely for layout purposes.
When the 4-byte header (shown in red) is inserted in front of the 'Media code'-block it will result in a slightly different looking hex dump :
|
** INFO : 4-Byte Header Preceding 'Media
Code'-Block Discarded ** INFO : 4-Byte Header
Preceding 'Media Code'-Block Present |
| Known Issues And Limitations |
On DVD+R/+RW the blank disc capacity will only be reported when the drive supports ADIP retrieval Method 1. No limitations exist regarding the blank disc capacity when handling DVD-R/-RW discs.
When dealing with DVD-R/-RW discs many drives will only report a partial 'media code'-block. This makes it impossible for 'DVD Identifier' to determine all of the disc's certified recording speeds since not all of the disc's write strategy information is accessible. Because of this issue 'DVD Identifier' will not report the certified recording speeds of these types of discs. However, the 'Drive capabilities'-tab will still provide you with the information regarding the capabilites of your drive in relation to that disc : i.e. it will still show the speeds at which the drive is capable of writing the disc.