View Issue Details

IDProjectCategoryView StatusLast Update
0001804OpenMPTGeneralpublic2024-07-25 19:26
Reportercartman1337 Assigned To 
PrioritynormalSeverityminorReproducibilityhave not tried
Status closedResolutionno change required 
Product VersionOpenMPT 1.31.09.00 / libopenmpt 0.7.9 (upgrade first) 
Summary0001804: Timing issue
Description

When exporting a track at a given BPM, the output file (tested at 48000hz) is not recognized at the same time signature in a DAW (tested in Ardour for my part).

Noticed this when working on a track at 122BPM as my first collaborative effort, and my collaborator mentioned that the track didn't quite fit the given time signature in her DAW. We discovered that changing the BPM in the DAW to 122.075 was very close, thought not quite 100%. In the track I've expanded the pattern from 64 to 128 lines, and thus changed the ticks/row from 6 to 3 to match. I just tested a simple beat three ways: in a 64 line pattern at 122/6, in a 128 line pattern at 122/3 and in a 128 line pattern at 244/6, which for my mathematical sense should also be the same.

The two 122 tracks came out the same length, but in a DAW there's a visible gap from a 122 BPM bar pattern already at the second kick, and by the end of the track it's way off.

The 244 track came out significantly shorter than the two others and was off by almost an entire kick after 4 minutes.

Steps To Reproduce

Make a simple beat at 122BPM, repeat for a couple of minutes, and export at 48000hz, and try to import in a DAW and try to read the file at the same BPM.

Additional Information

Not tested at 44100hz, so not sure if it's just an issue with 48000hz or in general.

Both DAWs were configured for 48000hz as well, so there was no transcoding on import.

TagsNo tags attached.
Attached Files
122BPM-test.png (69,997 bytes)   
122BPM-test.png (69,997 bytes)   
Has the bug occurred in previous versions?Yes
Tested code revision (in case you know it)

Activities

Saga Musix

Saga Musix

2024-07-25 19:24

administrator   ~0006019

Last edited: 2024-07-25 19:26

Please read this section of the manual on how tempo works in classic module formats and how it relates (or doesn't) to actual BPM: https://wiki.openmpt.org/Manual:_Song_Properties#Tempo_Mode

If precise tempo is important to you, you must use the MPTM format in modern tempo mode. Otherwise, go to Player -> Approximate Real BPM to find out the actual BPM the current speed and tempo setting are corresponding to.

Issue History

Date Modified Username Field Change
2024-07-25 19:18 cartman1337 New Issue
2024-07-25 19:18 cartman1337 File Added: 122BPM-test.png
2024-07-25 19:24 Saga Musix Note Added: 0006019
2024-07-25 19:24 Saga Musix Status new => closed
2024-07-25 19:24 Saga Musix Resolution open => no change required
2024-07-25 19:26 Saga Musix Note Edited: 0006019