Can you edit AVCHD files for length & keep them AVCHD?

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Can you edit AVCHD files for length & keep them AVCHD?

I shoot video on a Canon Vixia HF10 camcorder that records in AVCHD. I usually import these files into an event in FCPX and create optimized media when doing so. Then, when I archive the project, I delete the optimized files and just keep the AVCHD files (which makes the project archive much, much smaller).

I shot some video the other day but forgot to stop the recording at the end of about 30 minutes of footage. This resulted in the camera recording until it filled the 32 GB card. And I was shooting from 4 angles with 4 different cameras, so I got more than 100 GB of useless footage.

I'd like to trim the AVCHD files themselves so that I can get rid of the 3 1/2 hours of footage I shot by mistake, and make the AVCHD files much smaller. Can I do that? How would I do that?

The only thing I can think of is to import the entire files into FCPX, transcode them into optimized video, then trim the resulting ProRes 422 .mov files down in a timeline, and export them. But then I think that I'd lose some quality in the process (of trimming, exporting, and reimporting them), and I'd be archiving .mov files (which I don't want to do because they are so large).

I'd appreciate any advice.

iMac (27-inch Mid 2010), OS X Mountain Lion (10.8.3), Two internal drives (one SSB)

Posted on Jun 2, 2013 6:59 PM

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Answer 1

Jun 2, 2013 11:04 PM in response to JDLee

first, AVCHD is no video 'format', but mainly a file and folder structure standard. Within that, wrapped as 'mts', you'll find h264 encoded video. which leads to ....

second, h264 is no lossless format. even plain cuts makes a re-encoding neccessary, which 'multiplies' compression errors/loss.

imho, you have two options:

• import wisely 😉 FCPX allows to select on AVCHD import - no need to 'swallow' the fulll 16Gs of a card, if you need just 10min here and 20sec there, import these parts. … but even 'parts' are probably bigger in file size than original recordings.-

• if you dig deeper into your AVCHD files (cmd-click/Show Package Content), you'll notice, a single 1h recording is chopped into many mts files. you could identify the 'empty' ones, erase them, and give the free tool AVCCAM Restorer a chance to re-enact a standard compliant AVCHD-structure (=erasing some mts inside an AVCHD 'axes' the whole thing!).

Try with a test recording! Test with a copy! This is a workaround! .... no guarantee, it works.

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