GoPro Player

Pergam GoPro Player — Survey Video Review Manual

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1. What the GoPro Player is

The GoPro Player reviews the video recorded during an aerial methane survey together with the flight track. Every frame is tied to the position and the time at which it was filmed, so you can start from a detection — of which you know the time, or the coordinates — and land straight on the moment it was filmed.

Under the video the map shows the same instant on satellite imagery, so you can compare what the camera saw with what is actually on the ground at that point — a facility, a road, a field.

It runs in a web browser, and the recordings are read from your own computer: a survey day is tens of gigabytes, and none of it is uploaded to the server.

GoPro Player main window — The player with a session open: video on the left, flight track on the satellite map on the right, and below it the speed in knots and the altitude at that instant.

2. Signing in

Access is restricted. Each operator has a personal account: the page asks for the user name and the password, and the session then stays open in the browser until you sign out with the button at the top right.

Personal accounts are not a formality: the survey video shows customer sites, and knowing who opened what is part of handling it properly.

Note: If you do not have an account, an administrator creates one for you — see Managing users.

3. Opening a flight session

Press Open session and choose the folder of the flight day. The player goes through it and lists every recording it finds: pick one from the drop-down next to the button.

Choose the folder of the whole day, not that of a single recording: searching by time or by coordinates then covers the entire day, and the player switches recording on its own.

What the recorder writes

File	What it is
`video_HH-MM-SS_NNN.mkv`	The recording. Matroska (.mkv) as it comes out of the recorder; if an .mp4 of the same recording sits next to it, the player prefers that one.
`video_HH-MM-SS_NNN.srt`	Per-frame telemetry: for every video timecode, the position, altitude, ground speed and heading. This is what ties the video to the map.
`video_HH-MM-SS_NNN.gpx`	The track with UTC times. From here the player takes the time at which the recording began, and therefore the flight clock.

Without the .srt a recording still plays, but the map does not follow it and searching by time or position cannot reach it. The drop-down says so, marking the recording no telemetry.

Beyond an hour the recorder closes the file and opens another one (_00, _01, …). The player joins them back into a single playback: the bar covers the whole recording and you never have to know which file a given moment ended up in.

Tip: Nothing is uploaded. The browser reads the files from the disk where they already are — an external drive is fine — and the video is played from there. Choosing the folder does not copy or move anything.

4. The player

The bar under the video holds the controls. The timeline shows the position within the recording; the times at its two ends are the elapsed time and the total length of the recording.

Player control bar — The control bar: timeline, transport controls, the flight clock with the JUMP field, and on the right screenshot, settings and full screen.

Control	What it does
⏮ ⏭	Previous / next recording of the session.
▶	Play and pause.
🔊	Volume. Survey recordings have no audio track.
📷	Saves the frame on screen as a PNG image, at the full resolution of the video. This is the image that goes into the report.
⛶	Full screen, to look at a detail.
━━━	Click anywhere on the timeline to move within the recording.

5. The flight clock

The red readout marked GPS shows the time of the flight — the hour of the day at which the frame on screen was filmed — not the time elapsed since the start of the recording.

It comes from the GPS: the start of the recording is read from the .gpx, the offset within it from the .srt. It is displayed in the local time of the computer, the same convention as the Time column of the GLD detection table — so the time you read in the report is the time to type here.

Note: If the video has a timestamp burned into the image, it may differ by a few seconds from this one. That stamp is written by the camera's own clock, which is set separately from the GPS. The clock to trust is the GPS one: it is the same clock that timestamps the detections.

When a recording carries no clock at all — no .gpx and no date in the folder — the readout switches to REC and shows the elapsed time instead, rather than passing it off as an hour of the day.

6. Going to the time of a detection

Type the time in the hh:mm:ss box and press JUMP: video and map both go to that instant. This is the quickest way in, because a detection is known by its time.

The search covers every recording of the session, so you do not need to know which one the moment ended up in: if it belongs to another one, the player switches to it by itself.

Result of a jump to a time — After a jump to 10:20:15: the player has switched to the recording that covers that time, the clock reads it, and the map shows the position at that instant with the part already flown in red.

Note: If no recording covers the time you typed, the player says so and tells you the range the session actually covers — between one recording and the next there are gaps.

7. Going to a position

Paste the coordinates into the lat, lon box at the top of the map and press GO. The player looks through the whole session for the sample closest to that point and goes there.

An amber crosshair marks the point you asked for and a dashed line joins it to the track: that line is the distance between the two, which the player also states in metres. A click anywhere on the map does the same thing — it answers “what was here?”.

Go to coordinates — Coordinates entered: the amber crosshair is the requested point, the red marker the nearest point of the track, and the message gives the distance between them.

8. The map

The track is drawn on satellite imagery: white for the whole recording, red for the part already flown, and the marker is the position at the instant on screen.

The button at the top right switches between the two framings: Whole flight, to see where you are, and Close-up 300 m, which follows the aircraft closely — that is the one to compare against the video, because at that scale you can make out the fields, the roads and the facilities that pass underneath.

Close-up map view — Close-up at 300 m: at this scale the field boundaries, the tracks and the buildings are readable, and can be compared with the video frame on the left.

Zooming and panning

The wheel zooms and dragging moves the map. The two work by a rule worth knowing: the map follows the position, and dragging is the only thing that detaches it. A jump, a coordinate search or either framing button re-attaches it — while the zoom level you chose is kept, because when taking a series of screenshots you want them all at the same scale.

While the map is attached, the wheel changes the scale only, keeping the aircraft in the middle. Once you have dragged it away, the wheel zooms on the pointer, as on any map. A ↺ reset view button appears whenever the map is no longer where the buttons put it.

The first time you look at an area the imagery is fetched and may take a moment to fill in; from then on it is kept on the server and appears at once, for everyone. Where the imagery provider has nothing at high zoom, a coarser layer shows through instead of a black hole.

Note: The imagery is not from the day of the flight. It is good for recognising a facility, a road or a field boundary; it says nothing about whether a field was ploughed that morning. The width of the frame is written at the bottom right, next to the credit for the imagery.

9. Speed and altitude

The two boxes under the map show the ground speed and the altitude at the instant on screen, taken from the recorder's own telemetry. In a session opened from disk the speed is in knots, the unit the aircraft is flown by: a survey runs at 40–50 kn, so a number out of place is recognised at a glance.

A track opened on its own from a KML (see next section) carries no telemetry: the speed is then worked out from the points themselves and shown in km/h.

10. A single video, or a track on its own

Open Video opens one video file from the disk, for when you have a single recording rather than the folder of the day. If the file is named the way the recorder names it, the player recognises it; otherwise it plays it as it is, without telemetry and therefore without a map.

Open KML reads a track from a .kml and draws it on the map without a video — useful just to see where a flight went. Export KML does the opposite: it writes the track on screen out to a .kml, and it puts the times in, which the recorder’s own .kml does not carry. In Google Earth a track with times can be played back; one without is only a line.

Note: Nothing is uploaded here either: the browser reads the files from the disk, exactly as it does with a session. That matters for a video, which weighs gigabytes: on a field connection sending it would take days, for a file that is already in the operator’s hands.

11. Managing users

Clicking your own name in the top bar opens Account & users. Everyone can change their own password there; administrators also see the list of users.

Account and users panel — Account & users: password change at the top, the list of accounts below with the actions available to an administrator.

Action	What it does
+ New user	Creates an account. The password is shown once, at that moment: write it down and hand it over.
Password	Resets someone's password — for whoever has lost theirs. Their open sessions are closed.
+ / − admin	Grants or revokes administrator rights.
Disable	Immediately ends that person's open sessions and blocks sign-in. It is reversible: use it for someone who is away.
Delete	Removes the account for good.

Note: The last active administrator can be neither demoted, nor disabled, nor deleted: without one there would be nobody left able to create users, and the way back in would be through the server.

12. If something does not work

What you see	Why, and what to do
The video stays black	The recorder writes Matroska (.mkv), which browsers do not open. The player repackages it on the fly, without converting the file, and this takes a moment at the start. If it does not manage, it says why: putting an .mp4 of the same recording next to the .mkv is the way round it.
The video plays but the map does not move	That recording has no `.srt` beside it, so there is nothing tying the frames to a position. The drop-down marks it no telemetry.
The time in the image differs from the GPS one	They are two different clocks: the one in the image belongs to the camera and is set separately, the GPS one comes from the satellites. The difference stays constant along the whole flight. Go by the GPS clock, which is the one the detections are timed with.
Zoomed right in, part of the map is blurred	The imagery provider does not cover every area at every zoom. Where the sharp tiles are missing, a coarser layer shows through: blurred, but there. Zooming out one step usually brings back a sharp picture.
JUMP says there is no recording at that time	Either the folder of a single recording was opened instead of the whole day, or that moment falls in a gap between two recordings. The message gives the range the session covers.