GitHub Issue #1499

[CCExtractor.org CI Platform]

Initialize data structures correctly for the rust CEA-708 decoder - PunitLodha
Link to Issue: https://www.github.com/CCExtractor/ccextractor/issues/1499
PunitLodha

Currently, the entry point for the rust decoder is here where we create a new Dtvcc struct each time. This causes the data to be reset each time ccxr_process_cc_data() is called.

Instead, we want to initialize Dtvcc only once at the start of the program and then use it for all subsequent function calls.

Steps:-

• Change Dtvcc::new() to create Dtvcc using ccx_decoder_dtvcc_settings as done here, https://github.com/CCExtractor/ccextractor/blob/master/src/lib_ccx/ccx_dtvcc.c#L76-L124
• Create a new extern C fn ccxr_dtvcc_init() in lib.rs and use this at all places where dtvcc_init() is being called. (Probably add a new struct field to lib_cc_decode like dtvcc_rust and store Dtvcc there instead of using the dtvcc field)
• Similar for dtvcc_free()
• Now change ccxr_process_cc_data to use Dtvcc from dec_ctx instead of creating a new one

Additionally to fix mp4 code flow:- - [ ] Call the corresponding rust function here and pass Dtvcc as done in the above steps