Vendor: Panasonic
Models: Lumix GH4
Compatible: some recording modes are common with Lumix GH3 and Lumix GH5
Status: Routinely repaired.
Panasonic Lumix GH4 was announced on May 2014 and is a mirror-less Micro Four Third system camera. This standard created by Olympus and Panasonic, grants that virtually any lens can be used on MFT camera bodies, as long as an adapter exists.
Panasonic Lumix GH4 cameras can record at 4K video and 24 fps continuous shooting. As 4K video camera, it can be categorized as pro-level video camera with record in Cinema 4K mode (4096 x 2160) or standard 4K Ultra HD (3840 x 2160) using IPB compression in 100Mbps. In Full 1080p HD there are two options, 200Mbps in ALL-Intra compression, or 100Mbps with no recording time limit.
They create QuickTime .mov files containing a H264 video track and audio Linear PCM format.
Panasonic Lumix GH4 cameras use the Venus Engine IX that is a quad-core processor first introduced in the GH4, and later used in the FZ1000, LX100 and DMC-G7. The Venus processing engine for digital cameras is an image processor developed by Panasonic, and almost all of their Lumix cameras use a version of it.
For a full comparison of Panasonic Lumix cameras, see dedicated wikipedia page.

Failure modes:
The causes of failure reported by Lumix GH4 users needing to repair files are:
- Camera locked up completely during recording or upon stopping the shot
- Camera turned off removing the battery after being irresponsive
- Last clip recording went fine but playback is not available
- "Cannot playback movie" error message
- Crash during file transfer from SD card
- Unplayable .DAT or .MDT video file
- Clips deleted, card formatted by mistake
- Clip not recognized after transfer, cannot play
- Battery dead during recording
Repairability:
The damaged files cannot be opened because recording did terminate abruptly: While the media (video and audio) is present and not corrupt, the index and header of the movie indicating what the data means, is not present.
Repair consists in reindexing the movie.
PRICING
Damaged files from Panasonic Lumix cameras are detected as "DSLR", and as such have an affordable pricing.
See Pricing Chart.