What “memory” does this error refer to?

Question

Software is Kdenlive Version 25.04.1

Operating system: Windows 10.

While producing the output video it is showing this:

I have plenty of HDD free size, nothing is close to this numbers (468 MB)

What “memory” is this referring to?

Answer 1

When you see "Memory" in an application, it almost never refers to available storage disk space on a computer. That is more likely to be called "space" or "disk space". On a computer, memory is nearly always RAM, fast and temporary storage for data currently being worked on, though it could mean any of a few different types of RAM, depending on your system and the application.

When you see a message that mentions "memory", the safest assumption, unless the message includes other details that change this, is that it is referring to the main RAM in the computer. Even when you're buying computers these days the system information will more often than not refer to "memory" instead of RAM.

In KDE you can use htop or System Monitor to view the currently available RAM. Video editing tends to be a RAM-intensive operation in many cases.

In Windows, Task Manager is a good place to start to see how much memory you have left and what is using it.

Answer 2

In this particular case it is possible to point to the part of the source code of Kdenlive 25.04.1 which generates that message.

The memory in question is the available physical memory, as reported by KMemoryInfo::availablePhysical(), which on Windows corresponds to the ullAvailPhys field of the MEMORYSTATUSEX structure returned by GlobalMemoryStatusEx():

The amount of physical memory currently available, in bytes. This is the amount of physical memory that can be immediately reused without having to write its contents to disk first. It is the sum of the size of the standby, free, and zero lists.

In some cases the low physical memory condition may be temporary (e.g., if there is a large amount of data which needs to be written to disk, and that disk is somewhat slow; this may actually be the video file data generated by Kdenlive itself). In other cases the problem may be caused by some applications requiring actual RAM, and not cached file data. You need to look at some more detailed performance monitoring data to find out what actually causes the problem, and what you can do about it.