MIDI file import - tempo problems

[jeremyroberts]

Here's a weird one that I've never seen:

Simple 1 track of midi.
tempo map EXACTLY as follows:

1.1.000 - 174 bpm (4/4)
80.1.000 - 136 bpm (3/4)
86.1.000 - 116 bpm (3/4)

If I export the midi file, then make a new session and import midi file (preserving tempo map) - the tempi appear as:

1.1.000 - 174.0003 bpm
80.1.000 - 136.0002 bpm
86.1.000 - 116.0001 bpm

I tried the following:

1. change sync to internal (was wordclock, 44.1) - session sample rate is 44.1
2. import midi file to Logic 6.4.3. It said initial tempo was 174.0002 - and other tempo changes were exactly as saved.

This is quite strange... has anyone experienced the tempo variations when exporting or importing midi files? This is a new one for me.

Thanks for any ideas.

[urumita]

It's happened to me while importing from CuBase SX. where the tempo in sx was a whole number and it showed up in PT with a decimal point followed by 001 for every piece I imported.
Since I was using the midi tracks as demos to build up some audiotracks, I ignored it and got to work. but it bothered me.
My files came in on a DVD from another computer, not from an export> import operation between different programs on the same computer.
I had audio tracks including a click track that were imported along with the midi and they were locked just fine with the PT click so I didn't worry. no drift or offset.
Maybe there's something you can set as a preference while importing midi but I don't remember ever seeing it, like a ticks vs sample thingy somewhere.
I didn't get a chance to re-export and import back to sx to see if everything was still synched when it went back there.
In fact I gave the producer a good deal on time not to go back to his home studio with the tracks just to avoid any problems I fantasized about because I saw those funny tempos and because the conversion quality in sx wasn't any good.
The time difference between 174 and 174.003 is a millisecond or so, that could cause a huge drift problem, 2 bars and you're already 8 ms off, you'd notice something strange by the chorus.
Try bouncing a click in logic and then export it with the midi and import both to PT, then record the click from PT and import everything back to logic and see if the 2 clicks stay locked up with the midi generated clicks through the whole process, then you have nothing to worry about as it's just an unexplainable difference between numbers.

[Ozzie]

Your mathematics are very wrong after 9 minutes you'll be out by 8 milliseconds.