Why are my trimmed QT movies larger than the original?

Question

Level 1

9 points

Why are my trimmed QT movies larger than the original?

I have a bunch of raw .dv files copied over from my camcorder that have never been edited or opened in any other program. When I open in QT X and trim the file, the trimmed MOV version is often larger than the raw DV. On one file, I even trimmed about half of it away and it still came out larger. I was under the assumption that DV is not compressed and neither is raw MOV,

After trimming the file and saving it, I select "movie" as the format since at this point I want to leave the files in as raw as a format as possible before I bring into an editing program like iMovie.

Any ideas?

Thanks

MBP, Mac OS X (10.5.4)

Posted on Jan 28, 2010 6:56 PM

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Answer 1

Jan 28, 2010 7:07 PM in response to pgallett

DV video is compressed.

After you trim your video do a SAVE AS. This should delete to trimmed video.

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Answer 2

pgallett Author

Level 1

9 points

Jan 28, 2010 7:21 PM in response to David M Brewer

Thanks for the advice, but didn't seem to help. I just took a 429mb .dv file, trimmed in half, did a save as "movie" (as suggested) and the resulting .mov was 495mb.

That said, I think it make sense now that you corrected me on DV being a compressed format (I've been living a lie). Plus, since it is compressed, I don't want to resave it to a compressed format and further degrade quality.

Thanks again

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Answer 3

Jan 28, 2010 11:12 PM in response to pgallett

I took a DV video that was 70 MB and trimmed the video. The new video is 40 MB. Doing a save or save as doesn't compress or add desegregation to a video. You can save a video over and over with no loss in quality.

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Answer 4

Jan 29, 2010 3:49 AM in response to David M Brewer

QuickTime X can open and view .dv files but can't save them as .dv files.
They will be re-compressed using H.264 video codec.
QuickTime Player Pro can "delete" or "trim to selection" a .dv file and the DV Stream codec will be placed in a .mov container at the proper (new) file size.

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Answer 5

Jan 29, 2010 4:16 AM in response to QuickTimeKirk

QTK... Saved or exported? When you save a video in QT X it doesn't recompressed the video does it?

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Answer 6

Jan 29, 2010 4:21 AM in response to David M Brewer

QuickTime X doesn't save from the original source codec. Save As will always become an "export" and a compressed file will be re-compressed.
I always use QuickTime Player Pro because simple edits are not re-compressed when the file is saved.

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Answer 7

pgallett Author

Level 1

9 points

Jan 29, 2010 6:30 AM in response to QuickTimeKirk

OK, so to circle back, any idea why I'm getting larger files than the original? I understand that the save as is being treated as an export and it won't use the same native dv codec. If the "Movie" formatting setting is compressed (I thought it wasn't), then it really doesn't make sense why their coming out larger.

On the flipside, if I take my native HD mov files exported fresh of my camera, when I trim and save those using the "movie" format setting, they are smaller in file size as one would expect.

thanks again

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Answer 8

Jan 29, 2010 6:58 AM in response to pgallett

Since QuickTime X doesn't have any export "options" (other than dimensions) a "raw" DV Stream format should always be smaller in file size.
DV Stream is about 13 GB's per hour of recording. A QuickTime X "conversion" would use H.264 video and AAC audio codecs and should be about ten times smaller in file size.
Are you sure your files are DV Stream?
In any event, QuickTime X may not be the best tool for the job.
QuickTime Player Pro doesn't re-compress the source codec if you use a simple "save" or "save as".
A regular "save" after doing any edits will replace your source file with the newer version. No way to restore any of the edited information so you should use save as (keeping the original).

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