Slow processing when adding multiple videos

[9jfcc]

Bug Report: One Video Takes Longer When Multiple Videos Are Queued
Describe the bug
When adding multiple videos to the tasks queue in Video2X, one of them takes significantly longer than expected. If I upscale a single video, it takes about 3 hours and 15 minutes, but when I add three or more videos, one of them takes 7 hours. The issue seems to be related to the CPU usage dropping to around 10% instead of the usual 30-40%, which causes a slowdown.

To Reproduce
Steps to reproduce the behavior:

Open Video2X (version 6.4.0).
Add multiple videos (3 or more) to the tasks queue.
Observe that one of the videos takes significantly longer than expected (7 hours instead of 3 hours and 15 minutes).
Expected behavior
All videos should take approximately the same amount of time based on the set parameters.

Actual behavior
One of the videos takes 7 hours instead of the expected 3 hours and 15 minutes.

Screenshots

Environment:

OS: Windows 11 24H2
GPU: AMD Radeon RX 6800 XT
CPU: AMD Ryzen 7 7800X3D
Video2X Version: 6.4.0 (also tested on 6.3.1)
Additional context
I noticed that the issue occurs when CPU usage drops to around 10% instead of the usual 30-40%. This happens when more than two videos are added to the queue, causing a slowdown due to the CPU not fully utilizing its potential. This has happened three times so far.

video2x-qt6.log

the Settings

The issue happens in SE and Pro. In Nose, if I add three or more videos, the program exits after upscaling only one