MPEG-1
TMPGEnc - [rating: C+] [free for mpeg1] [ver/tst: 2.52.34.129] MPEG-1 files. Cut off the beginning or end. Join multiple files. Cut segments and merge. The MPEG1 tools are free. Sometimes there are audio video sync problems, however, there are some workarounds that often clear up the problems. In TMPGEnc menu choose FILE, MPEG Tools, and click on the Merge & Cut tab.
MPEG-2
TMPGEnc - [rating: D-] [trialware for mpeg2] [ver/tst: 2.52.34.129] MPEG-2 VBR and MPEG-2 SuperVCD Files. Cut off the beginning or end. Join multiple files. Cut segments and merge. The MPEG-2 functionality of TMPGenc is "trialware" only. Also, TMPGenc cannot seem to keep the audio synchronized with the video.
Mpg2Cut2 - [rating: ?] [free]
AviDemux -
VideoReDo -
XviD (avi)
H.264 (mp4)