Most DVRs and dashcams that record in JDR format come with dedicated playback software, often found on the SD card or in the device's setup menu. This is the safest method to ensure no loss of data.
If you have stumbled upon a file with the extension .jdr and you need to play it on a standard video player like VLC, QuickTime, or your smartphone, you have likely run into a wall of frustration. By default, Windows, Mac, and Linux do not recognize JDR files. convert jdr file to mp4