Quite an old TV this one and the video formats it will play are a bit limited.
Click on the link below to the specifications for your TV,
https://www.sony.co.uk/electronics/support/televisions-projectors-lcd-tvs/kdl-40ex401/specifications
Scroll down to Picture, on the right hand column five from the bottom you will see
USB Video Player
Yes (mpeg1/divX,MPEG4) those are the three video formats your TV can play.
If you have video files in a different format you can convert them to MP4s (MPEG4)
using this free software available for Mac or Windows computers.
https://handbrake.fr/downloads.php
Although it may look daunting at first it is fairly ease to use it straight away using the programmes presets.
First you would select the file you want to convert (Handbrake can convert most video file types).
Depending on the resolution of the source file you then click on Preset> General and choose
the corresponding resolution the and the quality you would prefer.
eg if the source is a 720p file then choose 720p as the output resolution.
Fast, HQ and Super HQ are the different qualities. The higher the quality the longer the conversion
will take. If the original is not to great quality selecting HQ or Super HQ will not work miracles and
improve things. But hey you can experiment.
Under Summary make sure Format is set to MP4.
