stretching out a score (double all note lengths)
I would like to be able to stretch a score out, so that everything is twice as long, or squish it together so that everything is twice as short.
I want to turn all quarter notes into eighths, all half notes to quarter notes and so on (and vice versa). Speading the notes over 2 bars or to turn a piece of music writen in 2/4 into a score in 4/4. 
Comments
See https://musescore.org/en/project/doubletimev20, but be aware of #90721: Doubletime plugin crashes with Musescore 2.x
Just wanted to mention that this is a built-in feature in ScoreCloud. Ahem...
I needed this feature as well, but it appears that this only works on a single staff (of a multi-staff score) and within the staff only on the first voice. Also, for a two-staff instrument (like piano) only the first staff works and the second staff turns into rests only. Is there an alternative plugin to doubletime that actually works?
In reply to I needed this feature as… by pauldebra
No
In reply to No by Jojo-Schmitz
"but it appears that this only works within the staff only on the first voice."
Limited to the first voice: true
For the record, you can create a file with only voice 2 (-> exchange to voice1 -> apply the plugin -> re-exchange to voice 2, and copy-paste)
"Also, for a two-staff instrument (like piano) only the first staff works and the second staff turns into rests only."
Not exactly. This plugin (well, this version) is limited to 32 measures.
So, if the second staff is also in Voice 1, it will work by selecting a few measures (not the entire score with Ctrl + A), and then applying the plugin.
Or, use this version (I only increased the number of measures to 140: can be edited as you wish if not enough): pianodoubletime_v2_0_2.qml
In this case, you can select all, depending of course the size of your score.
Note the clef in second staff toggles in treble clef. You have just to change for bass clef after applying the plugin.