composite software package provides Live performance sequencer, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install composite
composite is installed in your system.
Make ensure the composite package were installed using the commands given below,
$ sudo dpkg-query -l | grep composite *
You will get with composite package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Sound |
| Package | composite |
| Version | 0.006.2+dfsg0-6 |
| Description | Live performance sequencer |
| Sub Section | Sound |