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Re: [Libcdio-devel] CD-TEXT documentation
From: |
Thomas Schmitt |
Subject: |
Re: [Libcdio-devel] CD-TEXT documentation |
Date: |
Mon, 06 Feb 2012 16:42:05 +0100 |
Hi,
> xor 0xffff is exactly the same things a mod 2**16. You must be talking
> about something else.
I understand it like this:
xor 0xffff inverts the lowest 16 bits.
mod 2**16 zeroes the bits above the lowest 16 bits. Like: and 0xffff.
The CD-TEXT CRC algorithm is ITU-T V.41 with the additional prescription
of inverting the 16 result bits.
MMC-3 Annex J states:
"CRC Field consists of 2 bytes. Initiator system may use these bytes to
check errors in the Pack. The polynomial is X16 + X12 + X5 + 1. All
bits shall be inverted."
My understanding of this prescription is backed by Leon's example data,
and by the fact that my burner refused to accept the CD-TEXT data when
i altered the 0x8f packs after computing their CRCs. (Educational mistake.)
The drive took the data as soon as i corrected those 3 CRCs.
> I'm just suggesting that rather than describe things bottom
> up, one might keep a human focus.
I am watching with high interest how you shape the libcdio documentation
and will probably make use of it when it does not move any more.
Have a nice day :)
Thomas
- Re: [Libcdio-devel] CD-TEXT documentation, (continued)
- Re: [Libcdio-devel] CD-TEXT documentation, Leon Merten Lohse, 2012/02/04
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/04
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/04
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/05
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/05
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/05
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/05
Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/06
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/06
- Re: [Libcdio-devel] CD-TEXT documentation,
Thomas Schmitt <=
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/06
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/06
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/07
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/08
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/08
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/08
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/08
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/08
- Re: [Libcdio-devel] CD-TEXT documentation, Rocky Bernstein, 2012/02/08
- Re: [Libcdio-devel] CD-TEXT documentation, Thomas Schmitt, 2012/02/09