[jmsl] start playback, but not at the "start"

[jmsl at music.columbia.edu]

Hello J

Yours could be a nice general purpose tool: starting at some time point 
into the MusicShape.  yes you'd iterate and accumulate until the total 
duration so far is >= your desired duration. Note that the desired skip 
duration may not fall on the boundary of an element (like jumping 
starting 3.5 seconds into a MusicShape whose durations are all 1.0).  So 
for that situation you'd probably want to use a startdelay of .5 seconds 
and then start playing with the element that would have fallen on the 
4th second. Either that or add a first element whose duration is 0.5 and 
all other parameters are 0 to keep it quiet.

Your design is good. I think you might be able to skip the Player 
entirely since you can launch a MusicShape directly.  Players are 
helpful if you want to perform a number of MusicShapes with the same 
instrument, in some sequence (either sequential or using a Behavior, 
since Players are SequentialCollections)

So without the Player, your description becomes:
...have a source MusicShape, then to locate the desired start point in 
the MusicShape, create a new MusicShape with only objects falling >= the 
start point,  then hand the new music shape the right instrument with 
newMusicShape.setInstrument(sourceMusicShape.getInstrument()), adjust 
for the "between durations" offset with 
newMusicShape.setStartDelay(littleDelay), and finally 
newMusicShape.launch(JMSL.now()).

This is not wildly better than your design, but I wanted to point it out 
since it may clean up some ideas about Player, MusicShape, and Instruments.

Thanks
Nick

jmsl at music.columbia.edu wrote:
> Okay, I was wondering whether I might need to make a new MusicShape with
> only the desired elements. I suppose this actually might be kind of good,
> since anything done during playback could be kept separate from the actual
> "object" of the original MusicShape. Anyway, this is definitely what I'll
> be needing to do. And I guess I would "skip the first accumulated 5
> seconds" just by iterating over the elements and summing their durations,
> yes? (I've always thought in terms of "ED" and "Duration", from Max-land,
> but I'll get used to this...)
>
> I suppose a possible design pattern for this might be to have a Player and
> a MusicShape, then to locate the desired start point in the MusicShape,
> create a new MusicShape with only objects falling >= the start point, add()
> that MusicShape to the Player, then launch. Sound about right? I suppose I
> could also calculate the actual offset of the first element beyond the
> desired start time, and add that to the playback start - i.e.
> Player.launch(JMSL.now() + offset). Yes?
>
> Thanks for your time.
>
> J.
>
>
>
> On Mon, 14 Jul 2008 15:04:10 -0400, jmsl at music.columbia.edu wrote:
>   
>> Hello J
>>
>> Welcome to the JMSL user base.  I am glad to hear you are diving into
>> JMSL and coming up with interesting scheduling questions so soon!
>>
>> You are right; a good way to schedule a bunch of MusicShapes in various
>> sequences is to put them in a SequentialCollection and provide a
>> Behavior for it. Behavior returns an index but there is no reasons why
>> it could not look up a MusicShape by name for example, find a match and
>> then return the index of the matching MusicShape.  But maybe I am
>> getting ahead of myself, by what means do you want to choose which one
>> executes?
>>
>> A MusicShape cannot be launched in the middle of its elements.  You
>> could build a nice auxiliary class that did so however, by creating a
>> MusicShape on the fly. (ie, if you want it to start 5 seconds into the
>> MusicShape, skip the first accumulated 5 seconds' worth of elements and
>> copy the rest into the MusicShape you actually launch. Make up for the
>> portion of the duration between elements with a startDelay)
>>
>> Does this help?
>>
>> TimePoint is used by JMSL's transcriber.  It's not relevant to this
>> discussion
>>
>> Thanks,
>> Nick Didkovsky
>>
>> jmsl at music.columbia.edu wrote:
>>     
>>> hmmm... Okay, so I figured out that I could make a Behavior-based
>>> object that chooses the desired MusicShape by index. But of course
>>> this implies that I know the index of the MusicShape.
>>>
>>> I'm wondering about TimePoint, but it seems pretty "thin", in terms of
>>> methods... By the description it sounds as though it should have some
>>> method like getIndexes(), and maybe getMusicShape(), but it only
>>> offers toString(). So I'm really not sure how I'd make use of it.
>>>
>>> I'll keep poking away at the docs, but if anybody can help get me out
>>> of the woods - just by pointing me in the right direction - I'd
>>> appreciate it.
>>>
>>> cheers,
>>>
>>> J.
>>>
>>>
>>> On 14-Jul-08, at 9:06 AM, jmsl at music.columbia.edu wrote:
>>>
>>>       
>>>> Hi All,
>>>>
>>>> I'm new to JMSL and just wondering how to start playback from a given
>>>> point in time.
>>>> I have a Player with n MusicShapes, but I'd like to be able to start
>>>> playback from an arbitrary point along those n sequences - is this
>>>> possible? Can I, for example, start from an arbitrary point using a
>>>> timestamp? Just like a basic play cursor in a sequencer.
>>>>
>>>> thanks,
>>>>
>>>> J.
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