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Old 08-16-2016, 06:32 AM   #1
Oleh
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Default Error MIDI editor in Reaper (FIXED)

Faced with the problem in Reaper!MIDI editor does not work correctly.After quantize notes are not smooth to the edge of the grid. Recording MIDI batch Quantize doing,get out of the MIDI editor ,increase the item ,and the notes are not exactly to the edge of the grid. Checked with a few people who use Reaper ,all have the same problem .Configure Reaper by default. What to do? Why is this happening?..In the video a good example.Attached the project with this error, it is evident in the second third fourth fractions .I would be very grateful to developers if it can be corrected.Thank you.

Video: https://www.youtube.com/watch?v=TONW...ature=youtu.be

Project Reaper: https://yadi.sk/d/aNfGS4veuFso7
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Old 08-25-2016, 07:38 AM   #2
juliansader
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This is very weird.

Below is a screenshot of one of your notes (blue) next to a note that is correctly drawn (purple) and another note that is just one tick earlier than 5.3.000 (green).



When I render the take to a new take, the notes in the new take are all rendered at the correct, quantized positions. Also, when I open the Note Properties window, the note position is given as 5.3.000.

I wonder if this is a bug in the visual representation, rather than a bug in the underlying MIDI itself?

There have been other reports of MIDI not being quantized precisely, usually due to rounding errors and timebase being set to "time" (for instance, "Painted" MIDI Item position rounding problem (FIXED)) but I haven't seen anything like your problem before.
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Old 08-26-2016, 07:19 PM   #3
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I am not sure what the true cause of the problems was, or the technical reasons, but I notice that the item lengths and positions (similar to the note positions) are ever so slightly off: For example, the length of the items in the top lane are 4.07292 quarter notes each, instead of exactly 4 QN. So there might have been slight stretching or rounding errors.

REAPER doesn't apply edits such as length changes to items destructively until the items are glued (aka 'consolidated'), and in your project, REAPER still remembered the original recorded sources. The first MIDI note in the item in the top lane started at PPQ position = 70 instead of 0, for example, reflecting its position in the original source.

Once I glued each item to consolidate the length changes, the problems seemed to disappear: Each item started at PPQ position = 0, and the MIDI notes could be nicely quantized.

EDIT: The following threads have lots of information about the differences between position in ticks versus samples: Glueing MIDI items makes them "unquantized" (NO BUG) and MIDI note position.

Last edited by juliansader; 09-04-2016 at 05:15 AM.
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Old 09-04-2016, 02:04 PM   #4
schwa
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While the MIDI editor is open, displayed MIDI event positions can be edited or quantized to fractions of a MIDI tick (ppq). But the actual saved, loaded, and played-back positions are rounded to the nearest MIDI tick.

In your video, the temporary display of a perfectly fractionally quantized MIDI note is just how it is displayed. The actual note start event may be up to 0.5 ticks on either side of the grid line. (This is almost certainly not a perceivable difference; 0.5 MIDI ticks at 960 ppq and 120 bpm = about 1/4 of one millisecond.)

The only reason you are seeing this at all is because your MIDI recording does not start on the beat. After recording, you trim the left hand edge of the recorded MIDI to the grid, but that does not affect the actual start time of the recording. Instead, you could either start the recording on the beat and then trim it to a later beat, or else start the recording wherever you want, then trim the left edge to the beat and glue the media item. Either of those actions will cause the underlying MIDI recording to start on the precise beat, which will then mean that all later beats will fall exactly on an integer number of MIDI ticks, and the quantized display will exactly match the playback.

Really, though, it doesn't make a practical difference.
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Old 09-05-2016, 02:04 AM   #5
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Quote:
Originally Posted by schwa View Post
While the MIDI editor is open, displayed MIDI event positions can be edited or quantized to fractions of a MIDI tick (ppq). But the actual saved, loaded, and played-back positions are rounded to the nearest MIDI tick.

In your video, the temporary display of a perfectly fractionally quantized MIDI note is just how it is displayed. The actual note start event may be up to 0.5 ticks on either side of the grid line. (This is almost certainly not a perceivable difference; 0.5 MIDI ticks at 960 ppq and 120 bpm = about 1/4 of one millisecond.)
How can you not realize that this difference between "displayed and actual" is not acceptable in any circumstances and does not exist in any other editor based on visually arranging items and notes. You need to fix it.
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Old 09-06-2016, 04:46 PM   #6
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This bug report has turned into a insightful discussion of two distinct problems:
* Rounding in Source versus Project timeline
* Difference between "displayed and actual"

Good news: It seems that both of these problems will be fixed in v5.25!

ELP, if you have some time on your hands, could you please take a look at the most recent pre-releases and let me know whether the rounding error has been fixed in this thread as well as the other threads in which you commented?
* MIDI note position
* "Painted" MIDI Item position rounding problem
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Old 09-19-2016, 07:51 AM   #7
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This is exactly the problem I was having.

I was having the same problem as in the video in first post. It is solved by gluing before duplicating the items. Or gluing each time you quantize the notes.

Maybe ideally REAPER should force the item start recording to always be rounded to a 1/32 or 1/64 beat to avoid this issue. If it is MIDI being recorded only. When we record like that without punch-in, we don't really need it to be precise where it starts so a 1/32 rounding would be fine, because we mostly will always trim the left edge later to a beat too.
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Old 09-19-2016, 07:54 AM   #8
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Quote:
Originally Posted by schwa View Post
Really, though, it doesn't make a practical difference.
there is a case when it matters. If the note is a bit before(not after) the grid. You trim item(right edge) to grid, not expecting the note to appear, but since it is a bit before the grid, the note is triggered.

Last edited by heda; 09-19-2016 at 08:09 AM.
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