Neuron2/Don Graft has a new product which can speed up the transcoding of AVCHD and other h264 streams. It uses the new CUDA enabled drivers which work on the Nvidia 8xxx series or higher video cards.

The decoder is similar in usage to his DGavcdec package. A few features:

1) No longer Libavcodec based, so many more types of AVCHD camera files will convert without artifacts.

2) Can use the built-in Nvidia deinterlacer, which is fast and the quality is excellent.

3) I've tested some conversions using my old Nvidia 8500GT card and v177.92 of the drivers. In some cases, performance was 3x faster than the standard DGavcdec version.

Not free ($15), but worth the money if you're converting a lot of files or are pressed for time. Although I haven't tried it, I suspect scrubbing in Premiere would be accelerated (if used along with the Avisynth for Premiere plugin)

http://neuron2.net/dgavcdecnv/dgavcdecnv.html

Of course, you need to have an Nvidia video card installed. And certain older 8000 series cards won't work. Your card must have VP2 capability. See this table to determine if your card is compatible:

http://en.wikipedia.org/wiki/Comparison_of_Nvidia_Graphics_Processing_Units#Features_3


Example:

Here's a file which is problematic with the libavcodec based DGavcdec

p00005.mts

Notice the artifacts when it is transcoded with the libavcodec based DGavcdec

dgavcdec_p00005.mp4

And the absence of artifacts when transcoded with the Nvidia version of DGavdecNV

nvidia_p00005.mp4