MCN read/write not on CD-Rs?

vbimport

#1

Hi!

I wrote a program that gives me the “media catalog number” MCN of a CD. With a “commercial music CD” verything works fine on all the drives I have, they all read it correctly with my program and eg isobuster.

Nevertheless, when I burn my own CD with cdrecord and set the -mcn option, it’s different (on the same drives):
Some drives cannot read the MCN at all
Some drives report “MCN present” but give me crappy data
Some drives read everything just fine!
Of course I justed the same CD-R for all the tests.

For the tests , I burned CD-Rs and CD-RWs, on 2 different burners, all with the same outcome…

I double checked with programs like isobuster, the only difference is that it reports “not present” on drives where I get the crappy data and the “mcn present bit”

How is that? Are some drives sensitive towards “home-brew” subcode data? And if yes, is there a way to detect that so I know if a MCN is really missing or the drive has just problems writing it??

Thanks for any ideas
Maik


#2

If your burner correctly supports arbitrary Q
subchannel writing, it should not give any
difference with a cd-da, as the constraints on
cd-r are the same (>= 1/100 subcode block).

As for reading, all programs use about the same
command (except Plextools, which use yet
another Plextor secret command). The standard
CDB you should use is therefore : 42 00 40 02 00 00 00 00 18 00 00 00.


#3

Hi!

Well, the read command is right, no problem there.

I tryed the burning with both a Toshiba DR1312BK and a Mitsumi CR4804TE. How likely is it that both burners have the same firmware problem? With both drives, I get exactly(!) the same test results…


#4

Has the disc been written properly? To ensure that it is not a broken disc, use cdrecord’s -raw96r option!
Exactly this is what RAW writing even of plain audio CDs is good for…


#5

> How likely is it that both burners have the same firmware problem?

Dunno. Open your drives and check the chipsets maybe.


#6

Originally posted by alexnoe
Has the disc been written properly? To ensure that it is not a broken disc, use cdrecord’s -raw96r option!
Exactly this is what RAW writing even of plain audio CDs is good for…

Hmmm, I did that one from the very beginning on. I don’t think cdrecord would write it at all without that option? The funny thing is that SOME readers can read it and some can not - and all the readers can read the commercial ones


#7

It is also possible that your cdrecord does not create correct MCN data from your input.
It really should not matter whether or not you read from a pressed CD. MCN is just some Q-subchannel data, nothing more.

Do you use the latest version of cdrecord?


#8

Version 2.0


#9

Could you read such a not-really-working disc in clonecd, zip the sub file and upload it somewhere?


#10

You could check the subchannel file of CloneCD manually with this tool:

Subchannel Analyzer

Unfortunately the official site isn’t up anymore. You can also download the tool here.


#11


That one is from a pressed CD containing a MCN. The red marked number indicates that the following data is the MCN.

I don’t find any Q-mode 2 data in the file you sent me…I actually have no idea how any drive could find a MCN there :rolleyes: