On Mon, Mar 28, 2011 at 12:47 AM, Leon Merten Lohse
<address@hidden> wrote:
3rd attempt
Thanks for your persistence. It does pay off. By the way, after reading over the email, I realize that this
really should be going to the libcdio-devel mailing list which I've cc'd that on the reply.
Hello hello,
working on my current project, an audio cd analyzer, I noticed, that
libcdio's cd-text extraction does not give me the expected results.
After reading through the source code an the equivalent part in cdda2wav,
I wrote a small patch for libcdio's cdtext.c:
http://nopaste.yamagi.org/?509
adding isrc and mcn extraction from cd-text.
should also work more reliable now, when binary fields are present.
work on double-byte characters.
Thanks, this has been applied. But before we release it would be really good to be able
to test this code. Could you create a small CD image with multi-byte CD-TEXT that
we can use in testing?
Currently only block 0 out of 0-7 is read. Is that intended? Are there any
audio CDs using more than block 0? If so, we should add a way to read
them.
It's been hard to find CD's with *any* CD-TEXT on it let along things text
in things other than track 0.
I could not find any information on the data format for binary cd-text
fields. Does anybody know more? Would be neat to also extract those
information.
Concerning double-byte characters: Should we leave it to the user to work
with that or should the library convert it to a standard like encoding
utf8? Either way, it lacks a field in cdtext_t indicating double-byte
characters or the encoding.
I was also wondering why the cdtext functions do not have a cdio_ prefix.
Just a mistake. I'll correct that later.
Oh. And I found a little bug in the cdtext example code in the line:
const cdtext_t *cdtext = cdio_get_cdtext(p_cdio, 0);
I think the 0 should be substituted with i_track.
Yes, I think you are correct. I've chthat too.
Regards
Leon Lohse
03-27-2011:
I just found some other issues.
cdio_get_cdtext even returns a cdtext_t object, if there is no cdtext
information available. The documentation says, it would return NULL in
that case. Would be kind of nice to get that fixed.
The code appears to be (for GNU/Linux) in lib/driver/_cdio_generic.c funciton get_cdtext_generic().
The intent was that we couldn't find cd-text information whereas I think you want a test that all fields are
the empty string. Right? If so, the code could be changed. But this is slightly different.
I started to work on proper GENRE and DISC_ID field extraction today.
Might take a while though, because the documentation on the internet is
very thin and even inconsistent in the case if DISC_ID is binary or char.
I am also not at home right now, so I do not have access to very many test
CDs.
I also intend to implement extraction of the other 7 blocks and relate
them to their languages. Dunno how to do that, without breaking the API at
this point. Have to think about it a little more.
It looks like the next release may have to break the API for some changes to allow writing.
If anybody has information about CD-Text specifications and use other from
MMC3 draft, I would really appreciate to see them.
Thanks!
Leon
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