HDV is a particular and specific format (or standard), with audio that uses the mpeg2 codec at a bitrate of 25Mb/s with a resolution of 1440x1080.
AVCHD, just like HDV is a particular and specific format (or standard), but it uses the h.264/mpeg4 codec, a small selection of different resolutions as well as audio types
h.264 is a variant of mpeg4... very similar code but not an exact match
Many people seem to believe that just because something uses the h.264 codec then it's automatically classified avchd.... this is not the case. a Particular codec can be used in a number of different formats. A bit of confusion the other day with files from a canon cam. It was thought that because it uses the h.264 codec then it must be avchd. But because of the method of which the canon cam uses h.264 (it's housed in a MOV instead of the avchd standard MTS container for one thing)... it doesn't conform to the avchd standard.... so it's not avchd.
h263 and h264 are codecs.
As their different numbers imply, they are not the same codec.
h264 is newer than h263.
AVC is another name for h264
AVCHD is a high definition format standard using the h264/AVC codec.
mpeg 4 is a set of specifications.
h263 is included in Part 2 of the specification.
h264 is included in Part 10 of the specification.
There are several different file extensions used to wrap files that use the mpeg-4 specification.