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NetAthlon .NAP/.N2P File Format

Introduction

The .NAP (NetAthlon version 1) and .N2P (NetAthlon version 2) files are binary representations of rides. They contain similar data to their .RAW equivalents, but at a higher sample rate. They also contain a lot of data at each sample point whose meaning I have not determined, however there should be enough information here to extract the performance data.

Format

The format of the .NAP and .N2P files is identical, just differing in the version number in the header block.

Header

There is a short header record before the ride data, which is 12 bytes in size.

FieldOffset (bytes)Size (bytes).NET TypeUnitComment
Version04Single3 = NetAthlon 1, 4 = NetAthlon 2
Unknown44Int32Always 0?
Ride duration84Singleseconds
Total12

Ride Data

The ride data records follow. The format of each record is:

FieldOffset (bytes)Size (bytes).NET TypeUnitComment
Time04Single
Speed44Singlemph
HR84Int32bpm
Cadence124Int32rpm
Power164Int32watts
Grade204Single
Altitude244Singlem?
Unknown2876
Total104

NB: the speed data appears to be in mph.