Re: [Traverso-devel] CDRDAO export

[ben levitt]

Hi Nicola,

Thanks for all the toc-writing work!  I have a few thoughts below:

On 5/11/07, Nicola Döbelin <address@hidden> wrote:
> If there is no track marker at the beginning of a song, the part from position
> 00:00:00 to the first marker will be written to a pre-gap. If there is a
> marker at position 0, a standard pre-gap containing 2 sec. silence is added,
> as required (recommended?) by the RedBook standard. Generally, a pre-gap is
> only possible before the first track *of the first song*. So please add
> markers at position 0 to all other songs when exporting "all Songs",
> otherwise the first part will be missing.

Actually, I think most CDs with discrete tracks (not continuous mixes)
have a 2 second pregap before every track on the CD.

I think that eventually we'll want to have a way for users to set up
(independent of eachother):
- the start and end of the export range for each of the project's songs
- the start of each cd track within each song
- the PREGAP length or pre-START area for each cd track (probably as
a property of the track mark)

But I think that trying to do all of this using only the locations of
a single type of marker overloads their function too much...

> In case you haven't noticed, Remon added a function to burn a CD directly from
> traverso. It works great here, and IMOthis is a very important and unique
> (among Linux DAW programmes) feature. Thanks a lot, Remon.

This is super-cool!  And I also look forward to optional on-the-fly CD
recording that writes the audio data straight to cdrdao, instead of
writing wav files to disk first.  :)

> Please let me know if you agree that the handling of markers is ready for a
> 0.40.0 release.

I feel that it's not quite right, and I'm trying to figure out what I
would want to work differently for this release, given a single type
of marker...  (Long rant, summary at the bottom.)

So for a song with 0 markers, I agree that we should write the entire
song as one cd track, with a 2sec PREGAP only if it's the first song.
That one's easy.  :)

For a song with 1 marker, that's a bit ambiguous.  It could mean start
at the beginning and end here, or start here and go to the end, split
the whole song into 2 tracks at this point, or consider it a single
track with a potentially long pregap.  To be as consistent as
possible, I think that it should export the entire song and split the
song into 2 cd tracks at the marker.  (Since the bounds of the export
range are obviously not delineated by the user yet.)

For a song with 2 markers, one at the beginning, one at the end, we
should do the same as for a song with 0 markers.

For other songs with 2 or more markers, if the first marker is not at
position 0, we could either make the export start at the position of
the first marker, or have the export start at the beginning and have
the first track have a pregap.  I think export should start at the
first marker, and it should work this way for all songs, not special
cased for the first.

For songs with 2 or more markers, if the last marker is not at the
end, we could either make the export end at the position of the last
marker, or have the last marker denote the start of one more track
that goes to the end of the last clip in the song.  (It currently does
the second.  I think it should do the first.)


So to summarize: I think that we shouldn't allow editing pregaps until
we have a better UI for doing so.  Until then, I think we should just
always add an initial 2 second pregap to the first song, and then not
allow other pregap editing.

And for songs with 0 or 1 track marks, I think we should export the
whole song as 1 or 2 cd tracks, respectively.  (Assume the nonexistent
markers at the beginning and end.)

For songs with 2 or more markers, we should assume that the first one
is the beginning of the first cd track, and the last one is the end of
the last cd track.

One other tangential thing is that I think the End marker should not
use the CDTEXT TITLE to store "End".  I think instead that "End"
should not be stored in the marker, but just drawn next to the last
marker in the TimeLine.  That way, when you move the end back before
the previous marker, the new last marker will now say End.  (If people
agree, I'm happy to take this on.)


Alternately, if we do want to allow editing pregaps, I think we should
allow the markers to have adjustable width.  The existing marker-arrow
would be at the right hand edge of the marker, and the pregap range
would extend to the left from there.  (Although a pregap range for the
final marker in a song doesn't make sense...)

(Also, I agree with Jonathan that we should not support the cd index
concept, since it's not really used by cds, or supported by players.)

Phew!  What does everyone else think?

Ben