How can I convert the caption file format (.xml to .vtt)? I'm looking for your help and suggestion how to get started with CC conversion from .xml to .vtt.

We are having lots of flash files where we have xml to vtt during a project migration. I tried with many online tools most don't have solution for this.

Could you please help me how to start on this. Suggest me any tools/online converters which can do this job for me.

Thanks,
Siva
Closed Caption Converter claims to be able to convert from TTML (XML) to VTT captions. I don't have a source file unfortunately, so I cannot confirm. 

What tools have you tried thus far?