Greetings, and thanks for providing this service!
I have read some other posts on codecs here but remain unsure. Like many, I have come -- after decades of professional film photography -- to the rapidly changing and developing digital video world late, and with miserable electronics knowledge. Fortunately, I can't afford a camera with a really steep learning curve. Previously shooting with a Canon GL-1, I'm now shooting with Vixia HF200-series cameras. Much of my footage, comprising historical interviews, has simply been saved with little editing to archival DVD or Blu-ray discs, respectively, since I have no time to do more with it now and no script for a documentary.
On other advice, up till now I have been using MainConcept Program Stream NTSC or, for HD, Blu-ray 1920x1280 60i, with audio separately rendered as ac3, adn discs burned as straight data discs. I am wondering if there would be any quality advantage to using an H.264 codec instead of the MPEG2. If so, I am having trouble making out from the list which I should use. If I check 'Match project settings' in the options, for my HD, I see three codecs under Sony AVC; I if uncheck it, the list expands considerably.
I would be grateful for whatever guidance you may be able to give.
mpeg-2, incl xdcam ex, can have the same quality as AVC/H.264. It all depends on the bitrates used for each. Generally mpeg-2 will need a much higher bitrate than AVC for a similar quality. Bitrate determines the size of your files.
Do your own tests and let YOUR eyes be the judge on your material. AVC can have up to 2x lower bitrate than mpeg-2 formats. Note I said "up to". It is an extremely variable thing.
At the high bitrate of Blu-ray templates you will probably have trouble seeing differences between an mpeg-2 Blu-ray and AVC Blu-ray. Again, it depends on the source material.
Just to add to what Norman said, MPEG2 @ 25Mbps is equal in quality to AVC/H.264 @ 16Mbps. Since bit rate determines file size, you can get 40% more footage on a Blu-ray disc using AVC rather than MPEG2 but if your video fits with MPEG2 it really doesn't matter which one you use. In short, I would use AVC if my MPEG2 video didn't fit on a Blu-ray disc.
What I usually do is render to match my source format. So I render my HDV footage to MPEG2 and my AVCHD footage to AVC/H.264. No particular reason other than keeping things consistent.