On Sat, Feb 4, 2012 at 11:25 AM, Leon Merten Lohse <l...@green-side.de>wrote:
> Thank you Thomas! > > On Sat, Feb 04, 2012 at 10:06:41AM -0500, Rocky Bernstein wrote: > > > doc/libcdio.texi: > > > > > > Some of its aspects go beyond my own CD knowledge. > > > Nevertheless, i have to question some statements: > > > > > > > The first place the information can be recorded is in the R-W sub > > > > codes in the lead in area of the CD giving a data capacity of about > > > > 5,000 ASCII characters (or 2,500 Kanji or Unicode characters). > > > > > > How was the payload of 5,000 bytes computed ? > > > > > > > Probably from http://web.ncf.ca/aa571/cdtext.htm > > And this source is as wrong as Wikipedia is. > According to the Sony Tool Docs (DOC08), the whole CD-TEXT size should > not be bigger than 9216 and must not exceed 36864 bytes. This includes > the pack headers and crc information so the actual data size is two > thirds of it. That gives us a maximum of 6144 bytes of text data minus > 3*18 bytes of block information per block. Also a CD-TEXT field should > not exceed 255 bytes. > Unicode is definitely not a part of the CD-TEXT specifications. > I've removed from libcdio.texi mention of size limits and made note of the newly created document. Again, if this is inaccurate or confusing please jump in and make suggestions. I have a hard time correlating the discussion above to some concrete change that will make things clearer or less confusing. > > > The highest lead-in start for recordable CD media in my list is > > > 97m 49s 00f which means LBA -9975. Lead-in reaches up to LBA -150. > > > Each sector can take 4 text packs of 12 bytes payload = 471,600 bytes. > > > > > > MMC command READ TOC/PMA/ATIP could retrieve 65,534 bytes from lead-in. > > > > > > A CD-TEXT block can have only 253 payload packs of 12 bytes each. > > > There can be 8 blocks at most. 253 * 12 * 8 = 24,288 bytes. > > > > > > A single block (i.e. one language) can have 253 * 12 = 3036 bytes. > > > > > > > Afaik, the format is the same in lead-in and in program area. > > > > > > Is the statement about CD+G particularly about program area or does it > > > apply to lead-in too ? > > > > > Program Area CD-TEXT is always mentioned but was as far as I know never > implemented. Imho mentioning it is just confusing. > > Regards > Leon > >
