How to avoid audio drop-out & loss of video frame(s) due to file fragmenting?

[WhatAndGiveUpShowBusiness]

Lengthy recorded takes of, say, 30 minutes or more, shot on GH2 (1080p 24fps) end up being fragmented on the 32gb 45mbps cards I've been using. Fragments are a little over 6 minutes long. So far, I've only been editing them in iMovie; will be getting Final Cut Pro X fairly soon, so have yet to try answering this question with FCP. But in iMovie, I notice that there is loss of a frame or two worth of video, and brief audio drop-out, between successive fragments which end up as separate clips in iMovie. The audio drop out is a result of rapid fade to silence at the end of a clip and rapid fade in from silence at the beginning of a clip. Not sure why the fragmenting drops a frame or two between clips and creates this "valley" in audio. I should add that I converted raw .mts and related bundle of files as recorded by the GH2 into .mov files by using ClipWrap software; don't know if that introduced these undesirable effects.

Although the transition from one clip to the next is almost seamless in iMovie, it isn't quite. These audio and video anomalies due to fragmenting play as very brief but somewhat noticeable glitches.

Any workarounds or cures? Would SD card with more memory (64gb?) avoid fragmenting? I realize keeping takes shorter (maybe 6 minutes or less?) ought to avoid fragmenting, but I'd rather not have that limitation. Would FCP offer cures? Your thoughts...

 

[TheDingo]

All SD cards use FAT32 partition formatting, which means that the largest file that can be created on the card is only 4GB in size. Most consumer cameras get around this limitation by recording a long video as multiple 4GB file segments, which includes meta-data that describes how to reassemble these 4GB segments back into a single large video file.

...This means that when you want to edit a long video file, you must use the import utility of your editing software to import your video files from your SD cards. Your editor will then stitch together all the file segments back into a large single video file on your hard-disk without any audio-dropouts.

Never access your video files directly from your SD cards, as you must alway use an import utility to assemble the proper files on to your hard-drive before your can edit them.

 

[WhatAndGiveUpShowBusiness]

...This means that when you want to edit a long video file, you must use the import utility of your editing software to import your video files from your SD cards. Your editor will then stitch together all the file segments back into a large single video file on your hard-disk without any audio-dropouts.

Never access your video files directly from your SD cards, as you must alway use an import utility to assemble the proper files on to your hard-drive before your can edit them.

Thanks for that comment, Dingo. The FAT32 info suggests that even cards with more memory than 32GB will still fragment long video files.

While I'm using iMovie to edit, which I'll do until I buy Final Cut Pro X, I'm forced to go through conversion software that does the assembly. I've been using ClipWrap (about $50.00 U.S.). It looks at the bundle of files generated by the GH2, that are on the SD card of course, and processes them to yield .mov files that can then be imported into iMovie and edited. iMovie 11, the version I'm using, does not itself do the assembly and won't import/assemble or access .mts files. I'm hoping that somehow ClipWrap is introducing the brief audio fade-out/fade-in at the end/start of fragments, and also dropping a frame or so at each end. Or more accurately, I'm hoping that Final Cut Pro X will do a more seamless stitching together of fragment files. Will it? Or will another "interim" conversion program do a better job giving me .mov fragments that can be stitched together seamlessly?

 

[TheDingo]

I'm hoping that Final Cut Pro X will do a more seamless stitching together of fragment files. Will it?

I edit on Windows using Sony Vegas Pro and Premiere, and am not familiar with the best method of importing AVCHD files on the Mac. My understanding is that Final Cut X will import your files properly without any audio dropouts, but I can't speak from firsthand knowledge.

Perhaps one of our Mac users can confirm which Mac apps will import AVCHD video files correctly...

 

[WhatAndGiveUpShowBusiness]

...when you want to edit a long video file, you must use the import utility of your editing software to import your video files from your SD cards. Your editor will then stitch together all the file segments back into a large single video file on your hard-disk without any audio-dropouts.....

Following the trajectory of your comment, I took another look at ClipWrap, the software I've been using to assemble and convert the AVCHD (BDMV subfolder) files on the card to .mov files. Problem solved. All it took was reading the help manual, and then just highlighting multiple clips and telling the software to join them up into one large clip. Easy peasy. Worked like a charm. Glitches gone. Many thanks.