Created files are invalid

[cloudlena]

Problem on Strava

The files created by Encode are somehow invalid for some platforms. For example, if I upload the newly created file to Strava, it says "The upload contains bad data.".

I tried to debug them by having a valid FIT file (e.g., https://github.com/tormoder/fit/blob/master/testdata/me/activity-small-fenix2-run.fit) and running it through the following simple program:

package main

import (
	"bytes"
	"encoding/binary"
	"log"
	"os"

	"github.com/tormoder/fit"
)

func main() {
	testData, err := os.ReadFile("activity-small-fenix2-run.fit")
	if err != nil {
		log.Fatalln(err)
	}

	file, err := fit.Decode(bytes.NewReader(testData))
	if err != nil {
		log.Fatalln(err)
	}

	f, err := os.Create("new.fit")
	if err != nil {
		log.Fatalln(err)
	}
	defer f.Close()

	err = fit.Encode(f, file, binary.LittleEndian)
	if err != nil {
		log.Fatalln(err)
	}
}

Using FitFileViewer

When uploading the new.fit file to https://www.fitfileviewer.com/, it shows empty data (whereas the original activity-small-fenix2-run.fit file showed valid content):

Using GPXSee

Weirdly enough, https://www.gpxsee.org/ shows the new.fit file correctly.

Using RUNALYZE

Analyzing both files with https://runalyze.com/tool/fit-viewer, the main differences seem to be that new.fit has a lot of enhanced_speed, enhanced_max_speed, enhanced_altitude fields on its laps and records (whereas activity-small-fenix2-run.fit doesn't have any enhanced_* fields) and that new.fit always uses 0 as its local message type index.

Update: I did another test run where I removed the code that generates the enhanced_* field generation code from this library and even without those, neither Strava nor FitFileViewer would accept the file. So I'm guessing that those aren't the problem.

[cloudlena]

For reference, here are both FIT files:

files.zip

[cloudlena]

Using FIT File Tools

I just did another test, uploading the newly created file to https://www.fitfiletools.com/#/remover#remover. There, the shown data seems to be very weird:

I'm thinking, the issue might be that the timestamps are not encoded correctly.

[cloudlena]

Using Garmin Online FIT Repair Tool

Uploading the new.fit file to http://garmin.kiesewetter.nl/ yields the following error: Upload status: The file could not be uploaded. The following error occured: Unexpected end of file while parsing Name has occurred. Line 151558, position 9..

[tormoder]

Thanks for the report.

I'll try to look into this if I have some available time (together with your other PRs), but it may take a while.

[cloudlena]

Thanks, @tormoder! Is there any way I can support more or any more information you might need?