Synchronized video player


This tool uses the framework of Rashomon Project to play and adjust the offset of multiple synchronized videos. This tool plays multiple videos at the same time based on audio synchronization output or metadata when available. It creates a universal time line and allows for adjustment of time offset when necessary. It also specifies the location for each video on a map when possible.


  • Play multiple videos synchronously.
  • Location could be specified for each video.
  • Allow adjusting time offset or location information for each video.


Here is a manual describing how to use this tool in detail.

To use this tool, you have to upload a JSON file to our website. JSON (JavaScript Object Notation) is a data information entry following a specific format. In this JSON file, you need to specify the url of each video you want to display and the time offset of each video, that is, the time delay you want to apply for each video so that they could play synchronously. Duration and offset need to be entered in seconds.

The format of JSON file should look similar to the example given below. We support extra features like cameraLatLng (camera latitude longitude) and additionalInfo (additional information).

After you replaced with the information you need in the JSON file below, please save it with CTRL-S, or Cmd-S. To display the result of JSON file, you need to upload it by selecting it in CHOOSE FILE, and by pressing the UPLOAD AND PLAY button.

{ "mediaPath":"", "event":"Event reconstruction videos", "videos":[{ "name":"ERC000000.mp4", "offset":"34.6", "duration":"38", "additionalInfo": "The duration of this video is 38.2s. The camera is located inside a tall builing." },{ "name":"ERC000300.mp4", "offset":"1", "duration":"186", "cameraLatLng": {"lat": "50.4490", "lng": "30.5264"}, "additionalInfo": "The duration of this video is 186.3s. It was taken by a person with his cellphone." }] }


  • er_pair1, an example showing two videos being synchronized with geolocation information provided.
  • final_test_6v, an example showing six videos being synchronized.

Upload new JSON