Hey Paul,
Don’t worry, detail, although slightly time consuming 😉 is very good.
The joys of taking over a 3-camera project shot on 3 different camera models…
It sound like the key to your solution is to have the end in mind.
As in if you have delivery specs from client, then that is where you should start.
For now I would assume that you are going to deliver 1920 x 1080 HD.
But is it for Broadcast (terrestrial), streaming (YouTube?) or screen projection playback, or similar?
Based on the size of the file, your 50 fps second file at at 275,79 MB (v 4,94 GB for the 25 fps) suggests that there is a lot of compression going on, whilst 50 fps would add even more uncertainty as to where the full frames “land” in playback. (This is again depending on length of the clip – if a shorter 50 fps clip, then the compression could be the same)
“Would it be possible for the project to have gotten slower and slower
over time as a result of copying and editing footage from and between
different fps sequences into the main sequence?”
In theory yes – but this where it comes down to the specs of your system and drives (HDD / SSD – on USB / Thunderbolt / Raid and so forth)
One way of dealing with it, could be to edit each part (section) in different projects, and stitch them together in the end.
“the one with the problem had a different “Fields” selected”
Could be the problem, but that is assuming that all three cameras are recording in the same codec, in which case it is worth matching them up.
“The ones without issues are set to “No Fields (Progressive Scan)””
The whole “Fields” discussion is a red herring, as if you are shooting progressive, there are NO fields (although some codecs, potentially like a 50 fps recorded file, might “stuff” 2 full frames into one and call it fields – other smarter people here can elaborate on this).
Don’t know how far you are in the editing process, but I would consider re-encoding the 50 fps footage to a 25 fps file, like ProRes or similar – then that problem might be erased with very little, if any, degradation to the source footage.
“The channel I’m delivering to insists on “Upper First”.”
As your client has already shot in progressive, then that footage will always apppear as progressive in playback regardless of how the final master is exported.
If channel says “Upper First” I would check if they are more specific about the codec that they want you to deliver in.
There is nothing wrong in editing your camera source footage in progressive, and add vfx, title sequence, graphics, end roll and so forth in “interlaced” and export is it as interlaced master – your video footage will always remain progressive regardless of the final output.
You could edit the video, export the edit as a flat ProRes file, and then add all of the graphics etc on top of that in a PPro Sequence set to interlaced (1080i instead of 1080p), before doing a final pass for the end-client master.
I should add that some of my suggestions above, again depending on where the film is to be used, is possibly not a good idea to suggest in public…
(In a distant past I have worked on DV-Cam PAL footage mixed into a HD project, that was transferred to 35mm, and projected in ta large audience in a big cinema – difficult decisions had to be made to make that happen…)
Hope this helps.
Atb
Mads