Hi, > One small thing I've noticed is that there is mention to mm5r03.pdf > and that is not in the references.
Good point. I have looked up the equivalent spots in MMC-3: mmc5r03c.pdf, table 490 TOC Track Descriptor Format, Q Sub-channel => mmc3r10g.pdf, table 237 TOC Track Descriptor Format, Q Sub-channel mmc5r03.pdf 4.2.3.7.4 => mmc3r10g.pdf 4.2.3.6.3 > Overall the cdtext.txt feels to me like the audience is a computer > rather than a person. It is a description for developing CD-TEXT software. Goal was to collect everything that is known and can be confirmed. > Instead, I think it better to assume the audience are humans. Well, man cdrskin explains some user aspects of CD-TEXT. http://scdbackup.webframe.org/man_1_cdrskin.html The libburn API description mentions CD-TEXT with several calls: http://libburnia-project.org/browser/libburn/trunk/libburn/libburn.h I simply lack of any user experience with audio CDs and/or CD-TEXT. I can compose the packs, i can write them, i can read them, i can parse them, but whether and how they work on a CD player: no clue. > So I find it more user friendly to say you can store information > about 8 languages rather than say there is a limit on 8 blocks. Agreed. > The same kind of thing with mentions of xor'ing 0xffff. That is > C-centric computer jargon. The intent is that there's a 16-bit number > there, that's what I think the designers were interested in. So it is > equally valid to use a modulo 2**16 or if (x > 2**16) if the language > you have doesn't provide xor. I am currently not aware of the mathematical reason for the final bit inversion of the division residue. It is not equivalent to modulo alone (that would be and-ing, rather than xor-ing). In the model of polynoms there would be a subtraction or addition involved. To my knowledge the CD-TEXT CRC algorithm differs only by this final bit inversion from the CRC algorithm that is mentioned in ECMA-167 7.2.6 for UDF descriptor tags. The ECMA-167 example {0x70, 0x6a, 0x77} yields division residue 0x3299 and CD-TEXT CRC 0xcd66. ECMA-167 predicts 0x3299. Have a nice day :) Thomas
