Handle timestamp_16 fields in Garmin FIT files

garmin_fit_timestamp_16.py

#!/usr/bin/python
from datetime import datetime
import pytz

# https://stackoverflow.com/questions/57774180/how-to-handle-timestamp-16-in-garmin-devices
# http://www.nlvocables.com/blog/?p=969

dt_offset = datetime(2019,4,30,22,0,0,0)
print (dt_offset)
timestamp = int(datetime.timestamp(dt_offset)) - 631065600
print (timestamp)
timestamp_16 = 31132
print (timestamp_16)


mesgTimestamp = timestamp
mesgTimestamp += ( timestamp_16 - ( mesgTimestamp & 0xFFFF ) ) & 0xFFFF
print (mesgTimestamp)

print('New:', datetime.fromtimestamp(mesgTimestamp + 631065600, pytz.timezone('Europe/Zurich')))