Re: [Traverso-devel] CDRDAO export

[Nicola Döbelin]

Hi Ben,

Thanks a lot for your input.

On Saturday 12 May 2007 00:06:02 ben levitt wrote:
> Actually, I think most CDs with discrete tracks (not continuous mixes)
> have a 2 second pregap before every track on the CD.

I thought that was just due to the fact that the first generation of CD 
writers only supported TAO mode. Since software and hardware support DAO 
writing, gapless CDs are standard (in my experience, yours can differ, of 
course). I only have 1 or 2 commercial CDs which count backwards before each 
track, and they are all > 10 years old. (Or can there be pre-gaps withouth 
the player counting backwards?)

> 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.  :)

Hehe, I doubt this is going to work with cdrdao...

> 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.  :)

Agreed, but I would suggest to add a checkbox "Add 2 seconds gap between 
tracks" to make it customizable.

> 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.)

The problem is that having only 1 marker is not a valid setup. We could just 
inform the user about it and abort. Currently the part before the track goes 
into the pregap, and the part from the marker up to the end of the clip goes 
into track 01.

> 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.

Agreed, that's what it does ATM.

[...]
> 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.

Ok, that's basically how it worked before my latest changes. Does anyone have 
objections against removing all pre-gap editing for 0.40.0? Or should we ask 
the user? If there is audio data before the first marker, the options would 
be:

- write it to the pre-gap
- write it as a normal track (= add a marker at pos. 0)
- omit it and start at the first marker

> 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.)

I thought that it would confuse the user if there are normal markers which act 
differently than the rest of the markers, depending on their positon. That's 
why I wanted to have a dedicated end marker, which obviously distinguishes 
from normal markers e.g. by a different color (yet to be done). Your solution 
could work well, though. So if you want to give it a try, be my guest.

But please keep in mind that a dedicated end marker allows to abort the CD 
writing or export at any given point. E.g. if you want to export only the 
first minute of a song (for a test), just move the end marker to that 
position. It doesn't matter that there are markers behind the end marker, it 
just aborts exporting at the first endmarker.

> 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...)

That sounds like fundamental changes. I would be glad if we could postpone it 
to a later release. Otherwise we'll never make it to 0.40.0 ;-)

> (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.)

Ok.

Just a general question: Do you guys really use pre-gaps all the time? I've 
never used them at all, and I don't think I'll use them in future. Is it a 
matter of genre? Are there genres that use hidden tracks more often than 
others? Please enlighten me, I just don't see why pre-gaps have such a high 
priority. ;-)

Thanks again
Nic