Rick and Michael, thanks for helping me out with your suggestions! I
wound up taking bits of code from each of your approaches to get
something that worked for me. It is primitive but it is a start for
me... I will come up with more complicated versions and post them here
if anyone is interested.
Here is what I wound up with... let me know if you have any comments
or suggestions! I would love any feedback you may have!
;;This function shuffles the times of MIDI notes in a MIDI file with a single
;;function called MIDIShuffler. I wanted to create variations on Rex
file rhythms
;;to use in Reason, but it could be used anytime you wanted to jumble the notes
;;of a MIDI file up and spit out a new file.
;;This function does 4 things:
;; 1) grabs MIDI info from a file
;; 2) shuffle/rearranges the time slot values of the MIDI events
;; 3) sorts the MIDI events in the sequence
;; 4) exports the sequence to a new MIDI file.
;;An example call to this function might look like this:
;; (MIDIShuffler "reich8.mid" "testeroony.mid")
(define (MIDIShuffler input-file output-file)
(let* ((mymidiseq (import-events input-file :meta-exclude true))
(extracted-time-values (fold-objects #'cons mymidiseq '() :slot 'time))
(reordered-time-values (shuffle extracted-time-values)))
(loop for m in (subobjects mymidiseq)
for k in reordered-time-values
do (sv m :time k))
(setf (container-subobjects mymidiseq)
(sort (subobjects mymidiseq) #'< :key #'(lambda (m) (sv m :time))))
(events mymidiseq output-file)))
On 4/10/07, Rick Taube <[EMAIL PROTECTED]> wrote:
dont think you are crazy or stupid, just that doin destructive
operations isnt a good idea unless you really understand what you are
doing!
that said, you can use (shuffle ) orr whatever on subobjects to
scramble them, but if you want to put them back in the seq then you
will need to sort them first:
(defparameter mess (shuffle (subobjects myseq)))
...
(new seq :subobjects (sort #'< mess :key #'object-time))
alternately you can simply pass your unsorted list i to events
because events will schedule, or sort, the objects you pass it:
(events mess ...)
On Apr 10, 2007, at 7:22 PM, Landspeedrecord wrote:
> So you don't think I am crazy/stupid I suppose I should elaborate
> more.
>
> Let's say a Seq has 10 midi notes in it. Each note is merely an
> instance of the class "midi". Each note has slots for time, keynum,
> duration, amp. My view of the seq is a like a jar of marbles. When
> the seq is called by some function (list-objects or whatever), that
> function then orders the marbles based on it's time slot. Or
> alternately, the ordering happens whenever something happens to any
> time slot value in a seq, like when a new midi note is inserted at the
> beginning of the seq. Then all the marbles are rearranged and the seq
> is resaved to be called upon later.
>
> The point being that the ordering has to happen at some time based on
> the time slot value and if so, then one should be able to rearrange
> the time values.
>
> Sorry for all the verbage, I just don't want anyone thinking that I am
> trying to make time reorder. That is impossible. I am trying to make
> the note's time values reorder which is a different thing.
>
> Please let me know if I have this all wrong conceptually.
>
> Thanks!
>
>
>
>
> On 4/10/07, Landspeedrecord <[EMAIL PROTECTED]> wrote:
>> Thanks Rick! Using fold-objects in conjunction with cons would have
>> taken me weeks to figure out so I appreciate your help.
>>
>> However, what I want to do is exactly what you are saying I
>> shouldn't.
>> The only thing I want to shuflle/reorder is the midi time. All the
>> other midi information (keynum, duration, amp, chan) is supposed to
>> stay together so that the notes remain the same but just come out
>> in a
>> different temporal order. Why do I want to do this? Because I am
>> trying to manipulate midi files that correspond to .rex files
>> (chopped
>> up rhythms produced by propellerheads recycle). If I can rearrange
>> the
>> midi file I can come up with endless variations of the looped audio
>> file.
>>
>> I am confused. I thought the midi "time" value was just another
>> slot/keyword value of the MIDI class (i.e. the same as keynum or
>> duration). I figured that it was only until the seq was put into the
>> scheduler that the midi time became "cemented" in. Do I have it all
>> wrong?
>>
>> On 4/9/07, Rick Taube <[EMAIL PROTECTED]> wrote:
>> > you shouldnt "rearrange the time values" of the seq's objects --
>> the
>> > purpose of a seq is maintain a time-ordered list of events!
>> >
>> > assuming you want to scramble keynumbers or something like that you
>> > could do this
>> >
>> > ;; create a seq of midis
>> >
>> > (defparameter myseq
>> > (new seq :subobjects (loop for i to 100
>> > collect (new midi :time i :keynum i))))
>> >
>> > ;; look at the first ten
>> >
>> > (list-objects myseq :end 10)
>> >
>> > 0. #i(midi time 0 keynum 0 duration 0.5 amplitude 64 channel 0)
>> > 1. #i(midi time 1 keynum 1 duration 0.5 amplitude 64 channel 0)
>> > 2. #i(midi time 2 keynum 2 duration 0.5 amplitude 64 channel 0)
>> > 3. #i(midi time 3 keynum 3 duration 0.5 amplitude 64 channel 0)
>> > 4. #i(midi time 4 keynum 4 duration 0.5 amplitude 64 channel 0)
>> > 5. #i(midi time 5 keynum 5 duration 0.5 amplitude 64 channel 0)
>> > 6. #i(midi time 6 keynum 6 duration 0.5 amplitude 64 channel 0)
>> > 7. #i(midi time 7 keynum 7 duration 0.5 amplitude 64 channel 0)
>> > 8. #i(midi time 8 keynum 8 duration 0.5 amplitude 64 channel 0)
>> > 9. #i(midi time 9 keynum 9 duration 0.5 amplitude 64 channel 0)
>> >
>> > ;; gather the keynumbers
>> >
>> > (defparameter seqkeys
>> > (fold-objects #'cons myseq '() :slot 'keynum))
>> >
>> > ;; now shuffle the keynums and put them back
>> >
>> > (let ((mixedup (shuffle seqkeys)))
>> > (loop for m in (subobjects myseq)
>> > for k in mixedup
>> > do (sv m :keynum k))
>> > )
>> >
>> > ;; look at them again
>> >
>> > (list-objects myseq :end 10)
>> >
>> > 0. #i(midi time 0 keynum 60 duration 0.5 amplitude 64 channel 0)
>> > 1. #i(midi time 1 keynum 68 duration 0.5 amplitude 64 channel 0)
>> > 2. #i(midi time 2 keynum 15 duration 0.5 amplitude 64 channel 0)
>> > 3. #i(midi time 3 keynum 51 duration 0.5 amplitude 64 channel 0)
>> > 4. #i(midi time 4 keynum 29 duration 0.5 amplitude 64 channel 0)
>> > 5. #i(midi time 5 keynum 52 duration 0.5 amplitude 64 channel 0)
>> > 6. #i(midi time 6 keynum 35 duration 0.5 amplitude 64 channel 0)
>> > 7. #i(midi time 7 keynum 74 duration 0.5 amplitude 64 channel 0)
>> > 8. #i(midi time 8 keynum 25 duration 0.5 amplitude 64 channel 0)
>> > 9. #i(midi time 9 keynum 16 duration 0.5 amplitude 64 channel 0)
>> > CM>
>> >
>> >
>> >
>> >
>> >
>> >
>> > On Apr 9, 2007, at 6:52 PM, Landspeedrecord wrote:
>> >
>> > > I having been trying to rearrange the time values of a MIDI
>> file, i.e.
>> > > rearrange the ordering of the notes while keeping all the
>> other MIDI
>> > > information intact. I can load the MIDI into a seq object but
>> from
>> > > there I hit a brick wall.
>> >
>>
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