Just a moment...

Why did my camera split my footage up into multiple forms?

Jul-18,2018

If you record one long continuous clip, you may find that on the memory card there are actually multiple clips. Generally this happens most often when using SD or SDHC cards (instead of SDXC cards). The reason for this is because SDHC memory cards use the FAT32 file system, and the maximum file size on an SDHC memory card is 4 gigabytes. One way to minimize this issue is to always use SDXC memory cards; they use the exFAT file system, and can record files up to 48 gigabytes in length. On the SDHC card, FAT32 has a maximum file size of 4 gigabytes, and 4 gigabytes can accomodate about 20 minutes of AVCHD PH footage, or around 2 to 4 minutes of 4K or UHD footage. So if you're shooting UHD 24P and recording on an SDHC card for 6 minutes, what happens? Well, the camera knows to automatically split the recording into two files, close off the first file at the 4gb file limit and continue recording into the second file.

(When recording AVCHD, the camera will also create "pointers" for the two clips, so that each section of the clip "knows" that it is only part of a larger master clip and it will know what clip follows it, and what clip precedes it.)


For AVCHD, all of this is done automatically and seamlessly behind the scenes. When you view the AVCHD clip in-camera it will look as if there's only one clip on the card, because, essentially, there is only one clip (it just happens to be made up of several pieces, but inherently it's all intended to be treated as one continuous clip). If you use an NLE that is properly AVCHD-aware, it will know how to properly reassemble all the pieces into one contiguous clip, seamlessly and effortlessly. If your software doesn't recognize the attached nature of the clips, then you'll have to manually copy over all the pieces, and string them together end-to-end on your timeline. Note that some earlier versions of NLE software didn't know how to do this seamlessly, and would introduce small gaps between the pieces of a clip. That is a software error, not a footage problem! The camera records all the footage seamlessly. If your NLE software can't display it seamlessly, look into upgrades or fixes for your software; as of the time of this writing most if not all major NLEs can now seamlessly handle spanned AVCHD clips.


If you're recording UHD or FHD footage in MP4 or MOV file formats onto an SDHC card, you can expect that the camera will also make individual files at the 4gb limit (on SDHC cards) or at the 48gb limit (on SDXC cards). However, unlike AVCHD recordings, the camera will display each and every one of those MOV or MP4 clips with individual thumbnails, and they will import into your NLE as individual clips; you'll have to manually align them end-to-end on your NLE timeline. As a best practice, when recording MOV or MP4, it's best to stick to SDXC cards (capacity of 64 gigabytes or larger) instead of SDHC cards. SDXC cards have the much larger 48gb maximum file size and, accordingly, you'll be able to accomodate many reasonably long recordings without the camera needing to split long recordings up into multiple files. And even when it does need to split into multiple files, it should be comparatively few files, versus the many files that may be created when using an SDHC card. When recording (for example) 90 gigabytes of data, an SDXC card will do so while creating just two files (one 48GB, the other about 42GB). An SDHC card, on the other hand, will make about 23 files, all of them (except the last one) being 4GB in size.


As you can see, you'll have a much easier time dealing with long recordings if you use SDXC cards instead of SDHC for recording MOV or MP4 files. For AVCHD, it doesn't matter what type of card you use, it will always split files at 4GB file sizes. But, it's less of an issue for AVCHD because the bitrate is so much smaller, so you can record longer per gigabyte, and AVCHD includes file pointers that let you treat even a very long, many part recording as one clip.