It has free and paid editions.

http://www.videoartifact.com/va/

Program helps you to prepare footages from consumer or professional video cameras, digicams and V-DSLR.

It can remove MJPEG, MPEG, H.264, H.265 compression artifacts and digital noise, improves sharpness and color resolution up to 16 bit 4:4:4.

Restoration features:

• Script-based to work with unique cases. You can use many filters in any combination.
• 50+ specialized restoration filters work in Y, U, V separately in 8/16 bit.
• Possibility to use dozens of different type denoisers for different noise type.
• Accurate denoising that keeps micro details with no "plastic" effect.
• Removing of sharping halos.
• Linear color high quality spline-based resize to resize up to 4K. Resize halos can be removed.
• Precise halo-free radius-dependent sharping.
• Film grain emulation and 3D LUT grading.
• 4:2:0 8 bit to 4:2:2/4:4:4 16 bit chroma reconstruction.

It can be used in a post-production workflow if you use V-DSLR or consumer cameras.
Currently 50+ camera models supported and hundreds of compatible models.

Special features:

• Batch processing without GPU. Very fast: 5 fps for typical V-DSLR AVCHD source and 2 fps for 4K.
• Automatic joining of MTS, MOV and MP4 spans and renaming to yyyymmdd_hhmmss.mov format.
• Non-standard 16-255 to TV 16-235 levels conversion.
• ITU-R BT.601 ↔ BT.709 floating point conversion.
• NLE and DaVinci Resolve compatible workflow.
• Mastering to webm VP9/Opus or mp4 H.264/AAC 1080p/720p/360p/240p.

Examples with various restoration methods are available at http://www.videoartifact.com/examples/

Some samples:

Namely, I thought that GH2 native progressive files (24H or 24L) will solve all the problems with Broken Chroma upsampling which I experienced with GH1 "interlaced wrapped" progressive files. Now the situation is slightly improved. However, as I am really picky about the quality of my footage, I noticed that colour resolution of the clips, when imported into Sony Vegas and then exported by using loseless codec, is not retained. The colour (spatial) resolution becomes lower.

However, by importing the following Avisynth script

DirectShowSource("name_of_the_file.MTS")

ConvertToRGB

into VirtualDub and exporting by using the same codec, the colour resolution becomes much better. You can see 400% enlarged crop below (the first with Sony and the second with Avisynth-VirtualDub). Please, click on the first two pictures (left & central) to see enlarged view.

So, I still can't use direct way of editing my footage (direct import into Vegas) if the quality should remain on the highest level. So, the first step is to convert the footage, by using Avisynth-VirtualDub, into some codec (e.g. loseless or Morgan) which preserves entire colour information.

However, such workflow is possible with camera factory firmware/settings, but not if I use, for example, Sanity 5 patch/settings. When exporting Sanity 5 footage with Avisynth-VirtualDub workflow, I always get exported file which is more or less garbage (see the third picture) - the picture becomes worse and worse by time.

I know that majority of GH2 owners are probably satisfied with results on the left picture (note again that it's 400% enlarged detail). Unfortunately, I am not. :-(

Is there any other way to get high-quality footage from other lower-bitrate patch (I liked Sanity 5 due to a relatively low bitrate) by using Avisynth-VirtualDub workflow?