hybrids and tribrids are backwards compatable on the analog side .
meaning they work with 960h , D1 etc.
the only thing backwards compatable about hd-cvi is that if you have an hd-cvi 1080p dvr ,
it will work with hd-cvi 720p camera's .
but if you have a 720p hd-cvi dvr , you can only use 720p hd-cvi camera's . New HDCVI DVR now support 720p full frame & 1080p half of the frame rate
as far as I know , dahua is the inventor and sole mfg. of hd-cvi hardware .
although you can find hd-cvi equipment with different brand names on them ,
they are all made by dahua .Dahua CVI chip is outsource & can be purchase from main distributor, there are other DVR manufacturers but one of them has already close down.
and as far as I know , hikvision is the inventor and sole mfg. of hd-tvi hardware ,
which is also available with different brand names but are only mfg. by hikvision .Wrong, here is the manufacturer http://www.techpointinc.net/
as far as recorded picture quality goes , I do not know if sdi has any advantage over
cvi or tvi . that is what I was searching for when I found this post.SDI @1080p is digital, therefore it is still the best if you can afford it.