Limiting File Size

[Todd Olson]

Brand new to the forums. Hope this isn't an absolutely stoopid question. I just had a client call me and say they want the raw footage from a shoot, but the file sizes can be no bigger than 2 gB. First time for that one. I have a Canon C100 Mark II, just wondering if there's a way I can limit the recordable file size to 2gB. I've prowled the boards and the inter webs, but can't find any information regarding this.

[Pete Cofrancesco]

Odd request “Uncompressed, this yields about 560 GB per hour” A lossy codec like ProRes HQ would be more appropriate.

[Christopher Young]

When you say "raw" footage I guess you mean a native file format not actually RAW? If you mean a native to camera format then yes you can keep files to 2GB if you shoot in AVCHD where the FAT32 file size limit of 2GB will be applied on SD cards. Basically with AVCHD a new file is started approximately every ten minutes when that 2GB limit is reached. Most NLE software is designed to see a string of these 2GB files as one file if they have contiguous time code if your shoot spanned across that 2GB file size limit. So if you keep each take to around no longer than nine minutes it's not a problem as no individual file will be over 2GB.

If you drill down directly on the cards you will find all the individual AVCHD files. If any individual file is less than 2GB then it is a stand alone file with its own individual time code. All your over ten minutes takes will be seen as a single file by most NLE software on import. In many cases though the software just reports theses long takes as a single clip on import though in fact on the hard drive its is still a bunch of short 2GB files. Some NLEs will actually stitch all contiguous time code clips together and render them as a new single long file on import.

The problem with AVCHD is that if you are trying to manually stitch a bunch of these contiguous time code 2GB files together on a timeline you will find there is an audio 'glitch' at the join points, usually of about 12 frames or so. So yes you could supply your client with a stack of 2GB files straight from the card with long takes but they should be made aware of the issue of the sound break 'glitch' if they are going to try to stick them together manually somehow. Outside of NLE software there are a few utilities around that can properly combine and join AVCHD clips together without the audio causing issues at the clip boundaries.

A very important thing to remember is that you should keep the entire card contents together as the other folders on the card carry all the necessary information to enable AVCHD clips to be joined together seamlessly by most NLE software if that capability is possibly required. If you just grab the video clips off the card on their own and lose the rest of the card's content then you will never be able to join spanned clips together without having to edit your way around those pesky audio breaks.

Chris Young

[Todd Olson]

Got it. Thank you so much. I have no idea why they have the 2 gB requirement, it seems like more hassle on their end ultimately. It’s a government agency the work is for so obviously they have their requirements which may not make total sense in the practical world.

Yes, I should have said “native” not “raw”.

Thank you so much everyone. I really appreciate it.

[Pete Cofrancesco]

Government is often in the dark ages when it comes to tech. I imagine that they use FAT16 for their storage which has a 2gb file limit size. FAT32 has a 4gb file size limit. I remember using Firestore recorder and it would break them up into 2gb files, come to think of it many of the first camcorders with SD cards also had 2gb limit.

[Christopher Young]

I stand corrected yes Fat32 is 4GB. Whatever govt dept is asking for 2GB must be in the dark ages. Is there anyone out there really using FAT storage?

Chris Young