How do I splice video files together to make one file?

Although interlaced video has been heavily criticised by many, including the EBU (who express the hope that in future all original material will be shot in 1080p 50 for easy conversion to either 1080i or 720p); the fact is that it does work well. HDV (25i UK) viewed on some plasma screens (such as Panasonic) retains both sharpness and smooth motion while having much less motion judder than a movie (which is of course 25p). The motion judder of movies, though regarded by film enthusiasts as a 'desirable feature' that adds to the 'feel' of film, is actually only as acceptable as it is because film directors know that they must restrict themselves to slow pans. Hand-held material shot in 25 or 24p can look very juddery and confusing. The fact that HDV works as well as it does, and gives smooth motion on plasma screens, which cannot produce a true interlaced scan, suggests that these use good deinterlacing in hardware, and that they do in fact deinterlace every field to produce a 50p output to the screen. PC's do not currently support interlaced video properly, and the Windows media player, though it makes some attempt to deinterlace if presented with interlaced files from HDV, fails and produces vertical ripples that appear to be dependant on the size of the output image, and other factors. In general, good deinterlacing quite good results, if the de-interlacing option is turned on, but the fact that most laptops use a screen refresh rate of 60Hz and many workstations use 75Hz means that there are inevitable clashes with 25 or 50 fps material (UK experience). Ideally, UK users should use a video refresh rate of 50Hz or 100Hz and media players should be capable of de-interlacing from 25i to 50p, though this still leaves problems given that material on the Web is likely to be in both 25 and 30 fps. Currently the preferred approach seems to be to de-interlace edited material for the web, but this is problematic. Avid Xpress Pro currently appears to fail to do deinterlacing on its export options such as WMV HD, which results in unacceptable 'mice-teeth' on moving vertical edges. Although good quality de-interlacing is possible on HDV files, using third-party software, it tends to take a very long time (all night for half an hour or so). HDV has the potential to look extremely good on the Web, using 6 to 8Mbits/s as demonstrated on the Microsoft WMV HD showcase site, many have tried and failed to get comparable quality on the web from HDV because of the interlace problem. The showcase material is of course all from film, and therefore 24p to begin with, avoiding the deinterlace problem.