The Program Freezes after a Certain While

[ATATC]

As it is mentioned but not resolved in #249, the introduction of cameras freezes the program a while after it starts.

[ATATC]

I think I know the problem. In #89 we added a performance checker that can dynamically adjust the interframe interval. The minimum suggested interval can be 0. However, in Tkinter, calling Tk.after(0, ...) is dangerous as it causes pauses.

[ATATC]

Commit 1f1fc38 has eliminated the scenarios where the program completely stops. However, it also exposes the poor performance of the program. The next step would be to investigate where that poor performance comes from.

[ATATC]

The average time for it to encode the image to Base64 is 160ms.
The average time for it to decode the Base64 image is less than 1ms.

[ATATC]

The solution would be to increase the speed of the Base64 encoder.

[ATATC]

The Base64 encoder barely has room to improve, so I decided to run this time-consuming task using multithreading.