I contacted a source at Panasonic about what the ‘new video mode’ is on the official GH2 firmware update that is coming in December. It is a 24Mbit 1080/25p output stored in a AVCHD 50i wrapper, meaning you can finally extract a clean high bitrate 25p (progressive) feed from the camera for PAL broadcast work.
This makes the camera suitable for professional work in Europe and other PAL regions.
The video mode uses the old HDV trick Progressive Segmented Frame which you can read up on here.
Previously the PAL GH2’s 1080/50i AVCHD mode didn’t contain a progressive source - it was interlaced before the encoding stage - and had a maximum variable bitrate of 17Mbit, so this is a nice improvement for PAL users.
In terms of Vitaliy’s existing high bitrate 24p hacks and for NTSC shooters it makes no difference. But it will likely unlock the 25p sensor mode so that Vitaliy can add a native 1080/25p hack with i-frames and very high bitrates.
To extract 25p video from the GH2 post-official firmware update you will do a similar de-interlacing / pulldown as on the original PAL GH1.