What is the --rev_comp_mapping_barcode parameter in the QIIME1 script extract_barcodes.py?
As the help page says:


  --rev_comp_mapping_barcodes
      Reverse complement barcode in mapping before lookup (useful if barcodes in mapping file are reverse complements of golay codes) [default: False]


As the help page of extract_barcode says:


  --rev_comp_bc1
  Reverse complement barcode 1 before writing [default: False]


You seem to be doing two complete different things. extract_barcode.py is designed to


  format fastq sequence and barcode data so they are compatible with split_libraries_fastq.py


While the first one is for:


  demultiplexing of Fastq sequence data where barcodes and sequences are contained in two separate fastq files


So it seems that depending on the machine used or the previous processing you are given with the barcode in another file or together. I would advice to ask the person who gave you this data.