G Standards Conversion package contains two complex filters that have been designed to convert between the three standards of NTSC video (29.97 frames per second), PAL video (25 frames per second) and 24p (24 frames per second progressive). G Converter deals with the video to video frame rate conversions, and G Film Converter deals with the video to film frame rate conversions. Both plugins will correctly scale the converted clips if necessary.
Standards Conversion now comes with some useful toolkit filters that work in a similar manner to the main filters. G Pulldown Removal and G Pulldown Addition allow you to add and remove pulldown in the timeline, and G Map Frames allows you to manipulate frames and fields and produce nice slowmo from interlaced footage. G Advanced Pulldown Converter can be used to help if you've shot the wrong mode on, say, a Panasonic DVX100.
The Standards Conversion algorithms have been refined to work with both interlaced and progressive PAL and NTSC. In Version 2.5 the algorithms have been further refined to work better with Y'CbCr (commonly know as "YUV"), 10bit video and the chroma sampling of 4:1:1 NTSC DV. Additionally, support has been added to convert 60p footage from a Panasonic Varicam to 24p. In this case, Final Cut Pro does quite a reasonable job of converting from 60p to 24p, but you may find the Film Converter's solution more visually pleasing.
Both G Converter and G Film Converter work in a very similar manner. This method of working is necessary to bypass the poor in-built Final Cut Pro / Quicktime frame rate conversion and allow the high quality algorithms to work effectively. Also, if a change of clip resolution (scaling) is needed, the clip on the timeline should be nested to allow the plugin to work correctly. Again, due to limitations in FCP, the plugin must be correctly informed of the Source Pixel size of the video that is to be converted. If you find that there is not a setting for the source media you are using, then please email me at email@example.com for it is an easy task to add in the required sizes. For subsampled HD sizes you can use the full raster size: HDV is 1440x1080, but you can use 1920x1080 instead, DVCproHD1080 uses 1290x1080, but you can use 1920x1080 instead, DVCproHD720 uses 960x720, but you can use 1280x720 instead.
Although conversion will work on a sequence in earlier versions of FCP, I have not found this route reliable enough to recommend it's use. From FCP5 onwards, the converter only works with clips. Please use the conversions on movie clips rather than sequences.