Question 1

What is OVRLEY?

Accepted Answer

OVRLEY is a desktop app for turning telemetry data into video overlays. You import an activity file such as FIT, GPX, or SRT , choose the widgets you want, line them up with your footage, and export either a transparent overlay for editing later or a final rendered video that is ready to upload. I built it because I wanted something local, flexible, and not tied to a subscription. The focus is not only on showing data, but on giving you a proper layout editor so the overlay can actually look like your own project instead of a canned template.

Question 2

Is OVRLEY really free?

Accepted Answer

Yes. OVRLEY is free and open source. It is not a trial and it does not lock anything behind a paid tier. The idea was simple: people making ride videos, trip videos, training clips, or hobby projects should be able to build telemetry overlays without adding yet another subscription.

Question 3

Does OVRLEY work fully offline?

Accepted Answer

Yes. OVRLEY works fully offline . Your activity files, video, rendering, and export stay on your machine. You can test this by disconnecting from network after downloading OVRLEY - it still works. That matters because telemetry data can reveal where you were, when you were there, how fast you were moving, and in some cases health or training information. OVRLEY is designed so you do not need to upload any of that just to make an overlay.

Question 4

Do I need an account or internet connection to use it?

Accepted Answer

No account is required for use. You only need connection to download OVRLEY, and the app does not need a live internet connection to import files, edit overlays, or export videos.

Question 5

Is OVRLEY safe, and can I inspect the code?

Accepted Answer

Yes. OVRLEY is open-source and safe. You can run the website/app via your favorite antivirus, and you can inspect the code. The code is available on GitHub . If you care about privacy or just want to understand how the app works, that is the best place to verify the claims yourself. It also means feature requests and bug reports are public instead of disappearing into a support inbox.

Question 6

Why do I get security warning when running OVRLEY?

Accepted Answer

Both macOS and Windows require apps to be signed with a developer certificate. OVRLEY is not signed because it is open-source and free, and each certificate requires paying ~100 USD per OS per year. This is why the operating system will warn you that it is from an unknown developer. You can safely ignore this warning by clicking run anyway on Windows, or using the command supplied in INSTALL.txt on macOS. If you are really worried, you can get OVRLEY directly from Microsoft Store , where it is signed and notarized, or you can always compile it yourself.

Question 7

Why doesn't my video preview play?

Accepted Answer

If your video imports without a warning and the preview remains black - it is most likely a codec issue, especially if you can still hear the audio. Some action cams encode the videos as H.265/HEVC, which is not supported by default on Windows/Linux. Unfortunately OVRLEY cannot distribute the HVEC codec due to licensing. You can download the codec from Microsoft Store (or other places), or you can install it on e.g. Ubuntu via: sudo apt install -y ubuntu-restricted-extras . If you still have issues, try converting the video to H.264 using a tool like Handbrake .

Question 8

Which activity formats does OVRLEY support?

Accepted Answer

Right now the supported import formats are FIT, GPX, and SRT . FIT is usually the richest option for sport recordings because it can carry GPS, timestamps, elevation, and paired sensor data such as heart rate, power, or cadence. GPX is great for route, elevation, time, and GPS-derived movement, but it can be less complete for sensor-heavy activities. SRT is common when cameras or drones export telemetry as timed subtitle entries. If you want the more detailed breakdown, the dedicated activity formats page explains what each one can usually support.

Question 9

Which activities does OVRLEY support?

Accepted Answer

OVRLEY is not limited to one sport category. If your activity can be exported as a usable telemetry file, the app can usually work with it. That includes things like cycling, running, hiking, skiing, motorsport, sailing, walking, rowing, swimming, aviation and more. In practice, the limiting factor is not the activity label. It is whether the source file actually contains the fields you want to show.

Question 10

Which metrics and widgets can OVRLEY display?

Accepted Answer

The current set of 29 widgets covers broad range of metrics: route map, elevation profile, speed, distance, pace, heart rate, cadence, power, temperature, date and time, pace, heading, stroke rate, camera settings, vertical ratio, ground oscillation time, and several more specialized metrics when the source file contains them. See the widget support matrix for a full breakdown by format.

Question 11

Why are some metrics are missing in my activity?

Accepted Answer

Usually the missing metric was never present in the imported file. Especially, when a GPX file is export from external serive, sometimes it only contains the GPS track, i.e. location and elevation but no heart rate, cadence, or power. Some third-party apps also strip fields during re-export. And even when two devices both export GPX, they can include very different levels of detail. If you can, use the most original export available and compare it with the guidance on the activity formats page .

Question 12

Can OVRLEY read telemetry stored inside MP4 files?

Accepted Answer

Yes, OVRLEY can now parse telemetry embedded in MP4 files from most cameras of common vendors like GoPro, DJI, Insta360 and others. It tries to extract as much data as possible and also takes several approaches to sync the video with any external activity data. Please beware that these data may be lost if you edit/cut your clip after export from camera. See the MP4 telemetry section for more details on the technical challenges.

Question 13

Can you add widget X or metric Y?

Accepted Answer

Possibly, yes. Adding a new metric is typically easy - I just need to teach OVRLEY which tags to watch. New widgets are more work, but if they are universally useful, there is a good chance I can do it. Some requests are straightforward. Others need custom parsing, new widget behavior, UI work, and test data from real devices. If you have a concrete request, open an issue on GitHub and always include an example file that contains the data you want to show, otherwise I don't know what to visualize.

Question 14

Why does my video not sync with the telemetry?

Accepted Answer

The common causes are boring but predictable: the camera clock was off, the clip was trimmed or the file was exported in way that did not preserve the metadata about when it was created, e.g. and date of export is now the date of creation. Timezone mistakes might also confuse things, especially if the camera and the recording device were configured differently. The important part is you can always manually offset the video from start of the activity in the 'sync offset' panel on the right. Follow the import checklist to avoid common pitfalls before syncing.

Question 15

How can I sync my video in OVRLEY?

Accepted Answer

Start with a visible event you can trust: a hard acceleration, a stop, a turn, a lap marker, or something similar. Set a rough offset first, then refine it by comparing telemetry changes against the footage. Enter the offset in the 'sync offset' field in the right sidebar. You can either input it as number of seconds or use hh:mm:ss since start of the activity.

Question 16

The overlay starts correctly but drifts later. Why?

Accepted Answer

Drift later in the clip usually points to a timing mismatch rather than a simple start offset. Typical reasons are variable-frame-rate footage, duplicate or dropped frames, or timestamp inaccuracies in the original recording. OVRLEY cannot handle these footage anomalies.

Question 17

My route, speed, or elevation looks wrong. Why?

Accepted Answer

The first thing to check is whether you're displaying the entire activity or only a custom export time range. Both the route and elevation Profile widgets include a Show Full Activity option in the editor sidebar. When enabled, the complete route or elevation profile is displayed, regardless of the selected export time range. When disabled, only the portion of the route or elevation profile that falls within the export time range will be shown. Elevation can vary depending on whether the device used GPS elevation or barometric readings, and especially if the barometric sensor was properly calibrated. Speed can also differ when it is GPS-derived instead of recorded directly. OVRLEY can smooth or visualize the data, but it cannot enhance weak source telemetry.

Question 18

What is widget update rate?

Accepted Answer

Widget Update Rate controls how often a widget refreshes its displayed value relative to the video frame rate. For example, an update rate of 1/5 means the widget refreshes at one-fifth of the video frame rate. In a 30 FPS video, the widget would therefore update 6 times per second. This obviously makes the export much faster because you are rendering fewer frames, but it also makes the overlay look choppier as its effective fps is lower. The default is 1/1; update rates 1/2 and 1/3 still look good especially on less dynamic metrics (e.g. not power), 1/5 starts getting quite choopy. For transparent overlays, this might create compatibility issues in some video editors.

Question 19

Are there shortcuts or tricks to speed things up?

Accepted Answer

A few habits that help a lot. Do not export entire activity unless you need it all - try to export only sections/clips that you need - this will make everything much faster. Use a short representative clip while you are dialing in the layout. Fix sync before you start polishing design. Some keyboard shortcuts you can use - control the video player with space and arrow keys, delete key to delete selected widget, ctrl+c/v for copy/pasting a widget. More shortcuts are coming later.

Question 20

What export codec should I use?

Accepted Answer

Choose based on the output you actually need. If you want a transparent overlay to composite later in an editor, ProRes is the safest default because it preserves quality well and fits normal post-production workflows. If you want a final rendered video for broad compatibility, H.264 is the safest everyday option. H.265 can give you smaller files at similar quality, but support is less universal on older devices and software. If you want a quick performance reference with the formats that exist today, check the homepage benchmark section or the codec decision guide .

Question 21

What is a transparent overlay and a composite video?

Accepted Answer

A transparent overlay export gives you just the overlay graphics with alpha channel, so you can place them over footage later in another editor. In this way, you can cut or color grade your footage independently of overlay and you don't transcode your video multiple times. A final rendered video bakes everything together into one deliverable file. If you already know you want to finish the whole job inside OVRLEY, that can be simpler. If you still want flexibility in Premiere, Resolve, or something similar, the transparent overlay path can be a better choice. See the output mode comparison for when to pick each.

Question 22

Why can't I use OVRLEY in my browser?

Accepted Answer

Because rendering and exporting telemetry-heavy video is still much better suited to a native desktop app than a browser tab. Once transparency, high resolution, long clips, and codec support enter the picture, browser-based workflows get heavy quickly and become much harder to keep reliable across different machines. OVRLEY is built around local desktop rendering and encoding for exactly that reason. I may eventually build a lighter browser-oriented version for simpler jobs, e.g. 1080p clips for social media, but that would be a different tool with different tradeoffs.

Question 23

Why is hardware acceleration disabled?

Accepted Answer

Hardware acceleration depends on the encoder, your hardware and operating system, and the installed drivers. So even when a machine has dedicated graphics, a specific accelerated encoder may still be unavailable. That is not unusual. It usually means the current codec or system combination is not exposing a supported path to FFmpeg. See the hardware acceleration guide for details on supported encoders.

Question 24

I have a GPU, but I still cannot use hardware acceleration.

Accepted Answer

The most common reason for this is outdated drivers. For example, FFMPEG used for encoding requires fairly recent NVIDIA drivers (v610+) to work. Second common reason is hardware compatibility. Just because you have AMD or Intel system, it does not mean that is has a specialized encoder chip supports AMF or QSV hardware acceleration. OVRLEY is smart about this - it tries to encode a primitive frame using every possible option at startup, and if it fails, it disables that option. Disabled option means that it really does not not work on that specific system. See the hardware acceleration section for a full list of supported encoder APIs.

Question 25

Why is my GPU not fully used during export?

Accepted Answer

That is normal with the current pipeline. At the moment, the heavy work is split: frames are rendered first on CPU, then passed to GPU and encoded there. So even when GPU-assisted encoding is active, the CPU is still doing a lot of heavy lifting and GPU will not be used at 100%. Low GPU usage by itself is not proof that acceleration is broken. Eventually I want to move the rendering to GPU as well with zero-copy encoding, but that is a very complex change that will take lot of time to implement.

Question 26

Why is exporting using Prores 4444 so slow?

Accepted Answer

Prores 4444 is a professional delivery format of high quality. It is designed to preserve as much detail as possible, including the alpha channel, which is why it is the best choice for transparent overlays. However, that quality comes with a cost: it is much slower than standard H264/H265 exports, there is very poor hardware-accelaration support for it and it produces very large files - about 120 GB per 1 hour of 4k footage. See the codec catalog for a comparison of all export options.

GENERAL OVRLEY FAQ

WHAT CAN OVRLEY READ AND SHOW

WHY SYNC GOES WRONG

EXPORTS AND CODEC QUESTIONS