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Converting mkv to Prores - Streamclip is duplicating frames

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Chris Punsala
Converting mkv to Prores - Streamclip is duplicating frames
on May 10, 2013 at 3:28:16 am

Hi,

I need to convert mkv files to prores movs for editing in FCP.

My workflow is this. Open mkv in QT7. Save as ref mov. Open in Mpeg Streamclip and export as PRORES 422 mov.

These files usually work fine but recently I noticed duplicate frames in the files. Specifically with an mkv file that is at 24fps. Compressor says it is 23.81 and Streamclip says 23.971. I tried forcing both rates in mpeg streamclip and it still comes out with duplicate frames. I've tried compressor and it gives me ridiculously long conversion times (213 hours).

Is it a timecode or drop frame issue?

Please help!
Thanks!


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Sreekumar Nair
Re: Converting mkv to Prores - Streamclip is duplicating frames
on May 12, 2013 at 10:44:24 am

Friend,

I would like to ask you how you are able to open .mkv files in QT7? I tried. Its not working.

Thanks


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Jeff Greenberg
Re: Converting mkv to Prores - Streamclip is duplicating frames
on May 15, 2013 at 2:24:04 pm

Sreekuma - it's because he has Perian installed.

Chris, I'd suggest just getting the h.264 content out of the mkv container. There's a utility I haven't used in a while called MKVtools (and MP4 tools) that should let you copy the h.264 into a different container (rather than re-encoding it.)

MPEG Streamclip is using Perian (built on FFMPEG) to handle the media. The problem is that Perian is dead...and the MKV container wasn't ever really meant for anything other than distribution.

>Is it a timecode or drop frame issue?

Perhaps - the person who encoded it (or their encoder) may have incorrectly encoded the frame rate. And it's the frame rate interpretation that's an issue (I believe). An easy way to test it would be to take a section and output it as a series of stills. Depending on what happens you can tell if it's duplicating frames.

So, I'll ask: where did you get the MKV files, can you get the originals and what was the original encoder software?

Best,

Jeff I. Greenberg
Author/Master Instructor/Speaker/Consulting
My contact info and more
New! Come see me speak @ NAB/Post Production World!


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