Requirements

The Hand Tracking Tool is a web app limited to use open-source web technologies. For this reason, the application only works with videos encapsulated in .mp4 or .webm formats, and encoded with h.264 codec.

If your video is already in .mp4 or .webm formats, try to upload it to the web app. If there is no video displayed on the site, then you need to recode your video to h.264.

There are many online tools to convert your video to h.264 and save it in .mp4 format. Including:

• https://video-converter.com/
• Bear File Converter
• Convert Files

Local processing

You can also recode your videos locally using FFmpeg. After installing the software, you can covert your files using the following command (in the command line or terminal):

ffmpeg -i INPUTFILE -vcodec libx264 -acodec copy OUTPUTFILE.mp4

For example, if your file is myvideo.avi, then your command shoud be

ffmpeg -i myvideo.avi -vcodec libx264 -acodec copy myvideo.mp4

you migh also need to provide the file with a full path.

Improving video quality

If you would like to improve the resulting video quality, is possible to manipulate serveral FFmpeg parameters. In particular, you can modifidy parameters as CRF and Preset.

CRF:

The range of the CRF scale is 0–51, where 0 is lossless (for 8 bit only, for 10 bit use -qp 0), 23 is the default, and 51 is worst quality possible. A lower value generally leads to higher quality, and a subjectively sane range is 17–28. Consider 17 or 18 to be visually lossless or nearly so; it should look the same or nearly the same as the input but it isn't technically lossless.

The range is exponential, so increasing the CRF value +6 results in roughly half the bitrate / file size, while -6 leads to roughly twice the bitrate.

Choose the highest CRF value that still provides an acceptable quality. If the output looks good, then try a higher value. If it looks bad, choose a lower value.

Preset:

A preset is a collection of options that will provide a certain encoding speed to compression ratio. A slower preset will provide better compression (compression is quality per filesize). This means that, for example, if you target a certain file size or constant bit rate, you will achieve better quality with a slower preset. Similarly, for constant quality encoding, you will simply save bitrate by choosing a slower preset.

Use the slowest preset that you have patience for. The available presets in descending order of speed are:

- ultrafast
- superfast
- veryfast
- faster
- fast
- medium – default preset
- slow
- slower
- veryslow

More information can be found here