Just stick with usb then and forget about SD cards.
Yes you can connect SD cards to a pc by way of a USB SD card reader. Start at a vouple of pounds.
MPEG2 is used in the uk for all standard definition tv and MPEG4 for all HD tv.
The video codec used in MPEG4 is the AVC codec the same as csn be used in mp4.
With any video file there are 2 aspects that must be correct for any device beit Panasonic device or pc, to be able to play it.
These are the container and the codec(s).
The container such as mp4, mkv or mpeg2, is the file stucture, i.e. how the video, audio, timing, description, control etc are all merged together into one file.
The codecs describe how the picture and how the sound are digitised and compressed.
In addition any file stored on a USB stick, SD card, hdd etc is stored according to the file structure of that device. This file structure, or format, such as FAT, NTFS, ExFAT, is the indexing system identifying where within the device particular files willl be found.
So for any device to be able to reproduce pictures and sound, the video file must be:
On storage media formatted to a standard that the device understands (eg Fat)
The file structure be a type the device understands (eg mp4 )
Encoded with a codec the device can decode (eg avc)
If any of these 3 are not of a type the device understands then playback will fail.
Whilst strictly it only needs the file structure to be acceptable inorder to copy the file, most devices are clever enough to refuse to copy if it knows it can't then play it.