Braille export

[Mario Lang]

David Kastrup <address@hidden> writes:

> Mario Lang <address@hidden> writes:
>
>> David Kastrup <address@hidden> writes:
>>
>>> Would it be useful if LilyPond could export BMC?
>>
>> Of course!  Actually, thats something that blind people are wishing
>> for for a long time so that they could make use of the huge body of
>> LilyPond music on Mutopiaproject for instance.
>
> I am skeptical that sighted people can easily make use of the huge body
> of LilyPond music on Mutopiaproject at the moment.

I am not sure what you are hinting at.  For a blind person, the
Mutopia content is virtually unusable except they are willing to read
music as lilypond input directly.  While that might be possible at
times, the typical practice of writing lilypond input as separate voices
across many measures makes it extremely hard to read keyboard music
(since you have to manually figure out what notes are played
simultaneious).

A sighted person would just fetch the corresponding PDF.
If they can read music they should be able to read what Mutopiaproject
has.

>> I am not sure, I think it would be quite hard to implement.  I have
>> looked at how to start such an endeavour at least two times in the
>> past and have never really understood the internals of LilyPond enough
>> to end up anywhere useful.  I guess what we need is a function that
>> receives music expressions and translates them into braille music,
>> outputting to some file.  However, the transformations required to
>> produce proper braille music are quite involved.  I'd be happy to work
>> together with anyone with enough Lily internals knowledge who would be
>> interested to attack this problem.
>
> It would probably raise more interest to first tackle MusicXML export
> and then use the code as a starting base for doing Braille as well.

Definitely.  I haven't come to that conclusion yet because off-list
discussions with people involved in LilyPond and MusicXML in the past
have suggested to me that the LilyPond community has no interest in
being able to export to ("an evil format like") MusicXML :-).

If that has changed, or was never true, I totally agree.  Braille music
export has likely a few things in common with MusicXML export.

>> Still, some of the algorithms necessary to produce proper braille
>> music could be (depending on the time signature and number of notes
>> per measure) quite computational expensive.  For instance, BMC has one
>> test case (bwv988 variation 3, \time 12/8) which needs about 4 seconds
>> of CPU time on a modern CPU, and that is C++ code compiled to binary
>> code.  Granted, this is an extreme case, and most other material I
>> have found yet doesn't explode so must complexity-wise, but I still
>> wonder if pure Scheme is a good approach for that.
>
> Computers are fast enough nowadays that the choice of implementation
> language is almost irrelevant compared to the choice of algorithm and
> consequently the algorithmic complexity.

Having experienced the difference between compiled and interpreted
languages first hand, I tend to disagree.  But I see your point, at that
stage of planning its too early to think about implementation details,
especially regarding performance.  Guess I am a bit biased since I spent
a few weeks recently finding optimisations for my current algorithm.

So I take it you suggest it would be best to start with a Scheme-based
impelementation, basically similar to what articulate.ly does?

-- 
CYa,
  ⡍⠁⠗⠊⠕