[Ardour-Dev] CD Marker Export in 2.8

[Andreas Ruge]

Hi all,

I'd like to suggest a few small improvements for the CD marker
export. I can provide a patch, but first would like to see, if there
are any comments from others.

I think that:

1. Cue sheets and TOC-files should both not link to their audio
files by using an absolute path but rather just the audio file
name--given that they both live in the same folder anyway.  This
would allow e.g. a cue/wav pair to be moved to another location.  I
can't see a reason, why we would want an absolute path here.

2. Cue sheet and TOC-file images should be name like this:

    myimage.cue
    myimage.wav

This seems to common usage among other applications using this
format.  Also there are (arguably broken) applications, that rely on
this naming convention rather then parsing the cue sheet's FILE command.

3. The cue sheet spec lists not only WAV and AIFF as file types, but
also BINARY and MOTOROLA referring to raw audio files with little
endian and big endian byte order respectively.  Ardour 2.8 should
use these keywords in the FILE command, given that the user has
chose that format (i.e. 44.1 kHz, 16 Bit, raw audio).  So far Ardour
uses the string "raw (no header)".  This string might make sense for
formats that are beyond the original spec anyway, but for example a
cue/bin image (using the file type BINARY) is a reasonably well
supported image format and Ardour should be able to export it.

4. On an audio CD when you skip to a track, you actually skip to the
track's "index 01".  Optionally a track can have an index 00 before
that index 01, which is often referred to as a "pause marker" or
sometimes even as the "end marker" of the previous track.  The span
between Index 00 (if present) and index 01 is known as pre-gap, the
counter on the CD player is supposed to count backwards in that
span.  For the first track a minimum of 2 sec. pre-gap is mandatory,
when filled with audio this is often called a "hidden track".

Cue sheets produced with Ardour list the index 00 even if the track
has no pre-gap.  This is not a serious problem, as reading
applications will most likely just ignore such an index command,
still while we are at it, I'd like to see that fixed.

5. This is a small one, but I'd suggest that cue sheets are indented
in what I think is the most common style among other applications:

  TITLE "cue sheet example"
  FILE "example.bin BINARY
    TRACK 01 AUDIO
      TITLE "First Track"
      INDEX 00 00:00:00
      INDEX 01 00:02:00
    TRACK 02 AUDIO
      INDEX 01 00:10:00

Aside from these issues I found two small bugs in the filename
mangling of the export dialog.

Any comments, thoughts, critic?

Andreas