Video format is not supported on your browser / operating system

You may have already encountered this message when you uploaded your video:

What is a digital video? 

A digital video is a file that contains images, sound, and text (metadata) placed in a container. In this container, images, sound, and text are compressed, as the infrastructure of the broadcasting networks cannot support the load of native audiovisual flows. It can be said that digital video files are the zip of the audiovisual media. The compression and decompression of these files are performed by codecs.
The container is a file format that contains audio and video streams, codec information, and metadata.
A codec (an acronym for code-decoding) is an algorithm for compressing/decompressing a digital audiovisual signal.

Container and video format:

The format of a video file is indicated by the name of its container (MP4, MOV, AVI, FLV, MKV, ASF, etc.). There are about twenty containers, the main ones are listed below. These containers have been developed over time by different companies and communities to adapt to technological developments. A container can encapsulate multiple audio and video tracks. Metadata can be title, abstract, keywords, credits, chapters, subtitles, etc.

For your information

A person tells you:
" - I send you my video in MP4 format"
This means that you will receive a file on a USB key or via the internet.

The main video containers: 

Video formats	Video extensions	Detailed audio and video coding	Supported platform
MP4	.mp4 /.m4v	AAC / MP3 / Voribis+H.264 / MPEG-4 / Xvid
MOV	.mov /.qt	AAC / MP3 / LPCM+ H.264 / MPEG-4 / MJEG
MPEG	.mpeg /.mpg /.vob	AAC / MP3 / LPCM+MPEG-2 / MPEG-4 / MPEG-1
AVI	.avi	AAC / MP3 / LPCM+H.264 / MPEG-4 / Xvid
FLV	.flv	MP3 / AAC / ADPCM+H.263 / H.264 (Avoir l'exception) / VP6
WMV	.wmv /.asf	WMA / MP3 / AAC+ WMV 9
MKV	.mkv	MP3 / Vorvis / LPCM+H.264 / MPEG-4 / Xvid

What is a codec?

Codecs are therefore essential to reduce the size of video streams. A codec is an electronic device or software used to compress and/or decompress a digital signal: it encodes to transmit, store or encrypt audiovisual streams and decodes them for editing or playback.
There are several hundred codecs (audio, video, text), each developed for a specific use. For the web, about ten codecs are sufficient (list below).

The most common video codecs for the web:

• FFmpeg MPEG-4
• MPEG-4 ou H.264
• HEVC - H265
• DivX
• Theora VP9
• x.264
• Xvid

A few words about HEVC: 

The HEVC (High-Efficiency Video Coding) codec (also known as H.265) is a video compression standard that allows GoPro to capture large video content, such as 4K60 and 1080p240, at about half the file size with equivalent image quality.

Windows

HEVC is supported on Windows 10 computers using the Intel Kaby Lake processor (or equivalent) and newer processors. 

macOS

HEVC is supported on macOS High Sierra computers using the A10 processor and newer processors.

macOS High Sierra computers supporting the HEVC format: 

• MacBook – 2016 or newer
• MacBook Pro – 2016 or newer
• iMac – 2017 and newer
• iMac Pro – 2017 or newer
• iMac 5K (2015-2017)  

What about my internet browser? 

Note that not all codecs are supported by all browsers: 

- For example, Firefox does not support native H264 encoding, the installation of an additional module is required. 

- The H265 is only supported by Apple and it's the codec used by 4K videos shot on the new GoPro.

If you want to upload a 4k video shot with your GoPro, a mac will be required. If you have a Windows machine, file conversion will be necessary. 

Here is an interesting WEB page listing browser-based video codec support: 

https://caniuse.com/#search=video%20format

Conclusion : 

The message this video format is not supported by your browser/operating system' is strictly related to your platform/browser combination. 

It is essential that you can play your video in order to synchronize it with your GPS track.