Span Confusion

N

nklaeser

Well-known member
Recorded a 1.5 hr. Program today with a HPX170 at 720p/60 on a 64gb card. I transferred the footage to an external HD like always and used my log and transfer in FCP 7.0 to begin editing. When I opened the footage in the log and transfer window I noticed that all the clips had a duration of 4 min. 55 sec and said partial span next to each clip. I do realize that my program recorded over onto my second 64gb P2 card but wasn't expecting all the clips to be partial spanned? Is there a setting somewhere controlling the input duration?
 
Any and every clip that exceeds 4gb will always be spanned. The FAT32 file system that P2 uses has a maximum file size of 4gb. So any clip that exceeds (about) 4 minutes, will be spanned over to another clip. Spanning doesn't just happen from one card to another, it happens any time a clip exceeds 4gb of file size.
 
I think I understand this but I've shot long form video before and when the log and transfer is complete I usually have one long clip as opposed to multiple clips that are 4:55 each. Doesn't make sense.
 
so, what happens when you shoot long form content and want to use the multicam function in FCP and you have a multitude of clips?
 
Your question would be better asked in our FCP forum, since it's a question specifically about FCP.

The HVX (and all P2 cameras) have always spanned clips at 4gb file sizes. The P2 file system knows how to connect the spanned pieces back together and, in an NLE that fully implements P2, you never even know that clips were spanned because the system presents them to you as one continuous clip.
 
Maybe I just haven't been paying attention, but I shoot with a 200 and/or 170 and have shot lots of long form stuff in plain DV and 720p30N. It seems that the camera only breaks a long clip up into 4 gb bites if the clip jumps to another card. If it stays on one card, I routinely get single clips that are 5, 6 gb and larger individual files. If it jumps from one card to the next, it will break it all up. Premiere seems to figure it out and knits it back together automatically, but FCP7 doesn't, or at least I haven't figured how to make it do that. I don't think I have ever used Panasonic's P2 software that I can recall... Am I misunderstanding something?

Thanks.
 
The files on the cards always, invariably, always, always get split at 4GB increments. If you use a 32GB card and record one continuous 32 minutes of DVCPRO-HD 1080i, and then look in the CONTENTS/VIDEO folder, you'll find there are eight files there, each of them 4GB or less.

It doesn't have a choice -- it MUST split the files up.

Premiere is aware of the file spanning and knows how to stitch the clips back together seamlessly to present you a single file.

FCP does a "log and transfer" which copies the contents out of the old files, and creates a new ".mov" file that has the contents of all the split files. Mac's file system supports larger-than-4GB files, so when FCP makes that new quicktime movie, it can be as large as it needs to be to hold all the contents.

There is no difference between an 8-minute file split up between two 4gb segments, and a file that spans across two cards. In both cases the larger continuous recording is made up of sub-4GB clips; it doesn't matter whether they span across cards or not, they're still spanned clips. Of course, it helps your NLE to understand the file better if you have all the cards present simultaneously, so it can find all the individual pieces and stitch them together.
 
This is where meticulous clear logging and transfer of P2 to hdd are critical. I typically don't do spanning. But for certain long-form events, FCP 7 log & transfer is flawless. Simply select all of the cam original P2 media that contains the spanned set and do the log & xfer. FCP 7 is smart in joining the spanned clip them. I did a 4.5 hour continuous take video on 5 P2 cards and not a problem. However, for future use, I do not recommend to record that long. The reason is quite simple. What if during the archival process there happens to be a bad Firewire or USB3 bit copy and it messes up the entire 460 Gb big file? This is a huge risk. This happens a lot more than you think but you won't know it until months later when retrieving the file. Despite P2's legacy 1980 DOS FAT16 structure, it's much safer to archive and restore smaller file size than a big single file. And P2 does this seamlessly. That's what matters the most despite it's a 34+ years old file system. If there's a skipped frame during the every 4 Gb .MXF for FAT32/P2 media, then I don't think P2 would ever be able to survive to this day. If there's a bad file, you can still use the other part of the clip. The max I'd ever go is 90-120 min of spanned clip.
 
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