Re: [Libcdio-devel] CD-TEXT documentation

[Rocky Bernstein]

I have made edits to libcdio libcdio.texi and cd-text.texi taking into
account what you report below. If this is not sufficient let me know.

http://jbum.com/cdg_revealed.html gives me the impression that CD+G uses
the R-W sub code in contrast to the program area that you report that CD
Text uses exclusively. I've tried to make that more clear.

As for a more automated or detailed reference from libcdio.texi to
cd-text.texi, that will eventually be done. Probably though it would be a
link to Internet url. Barring other suggestions or conflicting opinions I
am thinking under Documentation in
http://www.gnu.org/software/libcdio/



On Sun, Feb 5, 2012 at 5:24 AM, Thomas Schmitt <address@hidden> wrote:

> Hi,
>
> i pulled the current git and read over libcdio.texi and cdtext.texi.
> (Now at: efc5ebd30cbc0a88001b701bb7b9cb69275a0941)
>
> ---------------------------------------------------------------------------
> doc/libcdio.texi:
>
> To my eyes, the splitting of paragraphs still suggests that the format
> statement applies to program area only.
>
> Meanwhile i understand the CD+G statement as a reference to pre-CD-TEXT
> usage of R-W sub-channels. This matches well Leon's opinion about the
> de-facto non-existence of CD-TEXT in the program area.
>
> So i would now rather state:
> "
>  The second place the information can be recorded is in the R-W sub
>  codes in the program area of the CD giving a data capacity of roughly
>  31MB. But there are no audio CDs known, which make use of this.
>

>  CD Text information is stored in a format that follows the
>  Interactive Text Transmission System (ITTS) which is the same data
>  transmission standard used by such things as Digital Audio
>  Broadcasting (DAB), and virtually the same as the data standard for
>  the MiniDisc.
>
>  R-W sub codes may also be used for other formats which represent
>  text and graphics in applications such as CD+G (CD w/graphics).
> "
>
> (Replacing the two paragraphs:
>  "The second place the information ... MiniDisc."
>  "Traditionally the R-W sub codes have been ...  not at all."
> )
>
> -----
>
> The following paragraph still needs some update for the 21st century:
>
> "The methods for reading this data from a CD-ROM drive is covered by
>  the programming specs from the individual drive manufacturers. In the
>  case of ATAPI drives, the SFF8020 spec covers the reading of the RW
>  subcodes."
>
> If the reference to pre-MMC ATAPI drives shall stay, then it should
> at least be mentioned that MMC offers standard commands for retrieving
> CD-TEXT from both mentioned storage locations: READ TOC/PMA/ATIP and READ
> CD.
>
> -----
>
> "There is a separate document in this distribution describing CD-Text
>  information and how it is encoded."
>
> Shouldn't one mention the name cd-text.texi resp. cd-text.info here ?
>
>
> ---------------------------------------------------------------------------
> doc/cd-text.tex:
>
> Some meaning is lost here - at least to my german understanding of english:
>
> "@item Codes @kbd{0x86},@kbd{0x87}, @kbd{0x88}, @kbd{0x89}, @kbd{0x8d}
>  apply to the whole disc."
>
> You removed the word "only" from "whole disc only".
> The meaning of my original statement is:
> - these codes apply to the whole disc.
> - they cannot be attributed to particular tracks.
>
> -----
>
> "Pack types @kbd{0x80} (Title) and
>  @kbd{0x85} (Message Area) and are encoded according to their block's
>  Character Code."
>
> The first "and" is "to" in my text. Meant is that 0x80, 0x81, 0x82, 0x83,
> 0x84, 0x85 are encoded according to the Character Code (of 0x8f).
>
> There is a surplus "and" after "(Message Area)".
>
> -----
>
> "The two bytes constitute a 16-bit Big-endian number are decoded as
> follows:"
>
> Some glue text seems to be missing between "number" and "are".
>
> -----
>
> "The 12 payload bytes contain pieces of NULL- or @code{\0}-terminated
> texts"
>
> Is it appropriate to use "NULL" with two "L" here ?
>
> -----
>
> "       3 : libcdio source states: "cd-text information copyright byte"
>            Probably 3 means "copyrighted", 0 means "not copyrighted"."
>
> Is it appropriate to quote the own source code ?
> I.e. shouldn't "libcdio source states" be omitted ?
>
> -----------------------------------------------------------------------
>
>
> As for importing cd-text.texi into libburn, i first have to ponder about
> the
> intended audience of libburn's current cdtext.txt.
>
> It is originally intended as background information for libburn
> development.
> Not so much for the programmers of applications which use libburn. But the
> libburn API specs and the cdrskin man page already mention it.
> So i will probably have to restructure this part of libburn documenation.
>
> -----------------------------------------------------------------------
>
>
> Have a nice day :)
>
> Thomas
>
>
>