Can a .fit file contains multiple file headers?

Alan 26 days ago

Hi,

I download the SDK and in it, there is a sample file HrmPluginTestActivity.fit. In its header, the header size is 14 and the data size is 22588, so the total size is 22602. However, the actual file size is 25,121. After 22602, there is another file header.

It seems the file HrmPluginTestActivity.fit is actually the concatated of two .fit files. Is such a file valid?

Thanks

Top Replies

Ben FIT 25 days ago +1 verified

Those are called Chained FIT Files which are very briefly mentioned here.
https://developer.garmin.com/fit/protocol/

Chained FIT files are most commonly used with store-n-forward heart rate data collected…

All Replies

+1 Ben FIT 25 days ago

Those are called Chained FIT Files which are very briefly mentioned here.
https://developer.garmin.com/fit/protocol/

Chained FIT files are most commonly used with store-n-forward heart rate data collected during swimming activities. When at the end of the swim activity the wearable downloads a FIT file containing the HR data from the HRM, and then appends that FIT file to the end of the FIT Activity file created by the wearable.
https://support.garmin.com/en-US/?faq=YiUfgV2c6b8aAexTDsBxE6

When used, the HRM plugin merges the HR data from the second file with the record messages in the first file.

0 Alan 25 days ago in reply to Ben FIT

Thank you very much.