Why is the ERP video before projection different from the ERP video after back projection?

[Cassie-yuxiao]

1.The ERP video I used is:

2.Get the TSP projection video through the following command.
Command used for TSP projection:

Video with TSP projection:

3.Back-project the obtained TSP video.
Command used for TSP back projection

Video with TSP back projection：

Why is the ERP video before projection different from the ERP video after back projection?

[HIMOTHYProxy]

Take a look at those attachments, the underlined portions should have the same values. Make sure the first portion say video728-1.yuv the second should say video 728-1-45_45.yuv