I have a PVR supplied by Truevisions

A few videos saved on the PVR are on interest for my friends in Europe : has anybody experience on how to transfer video from the PVR to my desktop PC ? (eventually which kind of connecting cables to I need to plug the PVR in a USB port of my PC)

IMO that is not possible as they are encrypted.

If it is possible I would also be interested in this as I would saving lots of programs on my HDD

if encrypted or not it would take days and sometimes weeks to transfer as in not worth bothering with the likes of pirate bay handy to all.

If you are viewing Free-to-View/Air Satellite content over a standard DVB-S2 Satellite Set Top Box, many have the ability to make either "EPG-based" or "timed-start-based" recordings to USB drives, and the recording can be watched on a standard computer that has the correct drivers/software to open the 'container' files and play the digital content.

Unfortunately this usually isn't the case for a 'cable system' box, or 'subscription-based content' delivered via encryption as the licensing requirements of the media companies, content distributors and cable operators usually require a HDMI HDCP digital flag be set that forced the device to only play the material over a secure HDMI connection to a connected HD Display or Television, and encrypt any recording made via built-in PVR software that only allows playback on the exact same device that made the recording.

In these cases, while you may be able to see the files on the hard drive, you'd lack the keys necessary for decrypting the files.

Some PVR's will allow you to output HDMI HDCP 'flagged' or recorded content out via the lower-resolution 'Composite' port, but will block viewing attempts to utilize unprotected HDMI or Multi-Wire Component Video output. But even if the video was 'clear flagged' you'd have to make a live recording of the output, and re-encode the A/V signal back to digital.

While the specifics cannot be discussed on this forum, you might be able to do a search for other forums that support your specific box and glean enough information on how to make unencrypted recordings that can be accessed on a PC.