Compiler/TDA2SX: About tidl usecase

Tool/software: TI C/C++ Compiler

Hi  dear TIer,

I am working on vision sdk 3.8.

I have two questions about tidl usecase:

1) why there is a merge link in this case, and the inQueue number of merge is only 1.

2) about meta buffer 

In Alg_tidlpreproc, it only outputs videoframe buffer, no metaDataBuffer.

and in Alg_tidl_1 process function , it reads MetaDataBuffer from the previous link as inArgs of  the algorithm  and  also outputs MetaDataBuffer and VideoFrame Buffer.

But I didn't see how the input MetaDataBuffer of Alg_tidl_1 was set  in the previous link?

Thanks!