Third-party database reference in tp framework

In the Common folder of the tp Application directory, a class is created for the Controller to use.
Class A in the Common file removes the third-party library in the vendor.
Tp version 3.2.3





The problem is as follows:

1. the third-party library resources cannot be correctly referenced by calling the composer autoload. php file, prompting that the class I want to use does not exist
(I want to call the ffmpeg tool to crop videos)
I tried to reference it directly through require because many of the references involved think this is unreliable,
The problem cannot be solved by referencing through the vendor function.
Now
Require _ DIR _. '/.../../ThinkPHP/Library/vendor/autoload. php ';
Add use to reference

2. what is the relationship between use and require?


Not much. please help.

Reply to discussion (solution)

Take slice
Reference
Third-party class libraries
Call
Program Structure
Error message

For more information about how to automatically load composer

Remember that third-party class libraries should be placed in the ORG directory and referenced using the ORG function

Remember that third-party class libraries should be placed in the ORG directory and referenced using the ORG function

Besides location, can the information provided above show the program's error points?

Thank you. I have already solved this problem in other ways.
I personally feel that it is difficult to import tp to a third-party framework. It hurts.