File format considerations

I have a few hundred hours of analog home video that I’ve digitized in raw DV format. Mostly they are in 1-hour segments with each hour made up of multiple scenes and events. I was planning to use FCP to isolate each unique scene, convert them to H.264 format, and save each one as a separate file on my computer. However, I’ve learned that I could simply tag all the scenes in FCP without actually carving up the 1-hour segments. Everything would then be searchable and easy to find individual scenes including specific people in them. My question is, should I leave them in DV format or convert all the 1-hour segments to H.264 format first in order to save a ton of hard disk space? Will FCP work just as well whether it uses the raw DV files or highly compressed files in H.264 format? Is it safe to convert them to AV1 or HEVC format now instead of H.264?

I would use the original DV-25 video and export the edited project as H.264.

DV-25 will have a bigger file for achieving than an MPEG 2 or MPEG 4 files but DV-25 is not huge. You would also loose some quality if you trans-code DV-25 to H.264.

grensch wrote: I have a few hundred hours of analog home video that I’ve digitized in raw DV format. ...I’ve learned that I could simply tag all the scenes in FCP without actually carving up the 1-hour segments. Everything would then be searchable and easy to find individual scenes including specific people in them....

Correct. The ratings, rejects and keywords in FCPX are range-based, not clip based, so you can have multiple overlapping ranges. The FCPX skimmer is full-screen and very fast. This also avoids re-encoding since those marked ranges are simply metadata.

There's a 3rd-party utility FindrCat Pro which can save your ratings and keywords as searchable Finder tags: intelligentassistance.com/findrcat.html

grensch wrote: ...My question is, should I leave them in DV format or convert all the 1-hour segments to H.264 format first in order to save a ton of hard disk space? Will FCP work just as well whether it uses the raw DV files or highly compressed files in H.264 format? Is it safe to convert them to AV1 or HEVC format now instead of H.264?

You have already done one conversion from analog tape format to DV. In general you want to avoid multiple conversions to yet another compressed codec. However the original source material may not be of sufficient technical quality that you can tell a difference. You could try converting a few "difficult" scenes such as gradient grey, gradient blue sky, dark shadows on interior shots, etc, and see if you can tell a difference.

DV is 720x480 so FCPX on almost any hardware is fast enough to edit that as DV, H.264 or even HEVC.