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Canon EOS Crop Sensor for HD
APS-C sensor cameras including the 80D, 70D, 7D Mk. II, 7D, EOS M and Rebel models for HD video recording.

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Old June 7th, 2010, 03:49 PM   #1
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Mpeg streamclip- enormous file sizes

my work flow for getting 7D images to FCP is Philp Bloom's classic using Mpeg steamclip, converting to apple pro-res 442 (not HQ), 100% quality.
the thing is the file sizes are huge, 6GB for 3-4 minutes. is that normal?
any ideas on how to reduce file size without ruining quality?
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Old June 7th, 2010, 04:15 PM   #2
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That's normal. You could go to ProRes 422 (LT) and get smaller files of identical quality.
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Old June 7th, 2010, 04:20 PM   #3
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In my experience ProRes files are 2.5 - 3 times larger than the H.264 originals, so your observation is spot on. The reality is that as a general rule - the smaller the file (the more highly compressed the video) the worse the picture quality.

I'm currently shooting a documentary which is intended for theatrical release. My work flow is to convert all the H.264 footage to ProRes, and then treat the ProRes files as my "camera originals." I have put together a 4.5 Terabyte RAID array to hold all the footage that I'll be generating. I will be shooting 30 - 40 interviews plus various B-Roll so I could easily end up with 50 - 100 hours of footage. When the film is done I will put the RAID up on a shelf, as it is in effect the camera original for the footage.

You should consider, though, what the intended use is of your footage. The three most common (in ascending order of picture quality) are: internet, television, theatrical. If you are shooting a project for the internet, don't bother with ProRes. Instead, use a lower bit rate codec such as DVCPRO HD or XDCAM EX. If the project is for television or theatrical I would stick with ProRes. This will maintain the highest possible picture quality throughout the post production process.

Whichever way you go, do some pre planning. You need to figure out roughly how much drive space you will need to hold all your footage while you are working on the project. And, you will need to figure out an archiving strategy. Gone are the days of film negatives and video tape. With a file based camera such as the 7D you need to create a "camera original" to put in the archive.

Good luck!
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Old June 7th, 2010, 06:06 PM   #4
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I'd disagree with not bothering with ProRes if your destination is the internet. 8bit, MPEG2-based codecs like XDCAM don't hold up well to multiple generations of compression, so I'd say your workflow should be what determines the codec you use. I convert to ProRes and edit, then send that to Color for CC and render back to ProRes before sending it back to FCP, then go out to a ProRes master. Then from there I compress to h.264 for a web master, and that in turn gets re-compressed by Vimeo or YouTube. So the final video most people see is 6th or 7th generation (things like titles & overlays will have one more generation than everything else). Keeping as many of the intermediate generations as possible in a high quality codec will result in a much cleaner final result.
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Old June 9th, 2010, 12:29 PM   #5
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ProRes LT files are smaller, but I notice a pretty big difference in quality on a big screen.

I agree with the above post about keeping the quality high all the way through the production process until you have to do your final compressions. I use ProRes422, which is high enough quality for what I do. If I were going to get involved in extensive effects, I'd go higher.
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Old June 9th, 2010, 01:34 PM   #6
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Bill & Evan - I agree with your sentiments about keeping the highest possible quality all the way thru post. However, not everyone can afford to dedicate the hard drive space required to work in the highest quality codecs such as ProRes. In every production one must weigh the pros and cons and make compromises. And, the reality is that if you are producing videos to upload to YouTube, working in ProRes is probably
overkill. My advice is always to perform real world tests and decide what work flow yields an acceptable final product.
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Old June 9th, 2010, 03:31 PM   #7
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It's easier and getting very cheaper to store your files, especially as the use today might not be the use for tomorrow. I dedicate the space to store high res files transcoded by Neoscene. Down the road there maybe a better transcoding option, so I store a "raw" h.264 and a transcoded one plus the final output file I'm using today. With 1TB hard drives at less than $100 Canadian$ I keep buying them.
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Old June 10th, 2010, 09:51 AM   #8
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thanks fro all you replies.
storage is a problem but as has been noted, prices for hard drives are coming down.
my biggest problem is the time it takes to transcode. i guess i need more ram.
i have a PPC mac so i can't use proresLT
i guess i just need to plan ahead and probably select the parts of the clips i want to transcode rather than transcoding everything.
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Old June 11th, 2010, 03:19 PM   #9
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Yes, that's important. Like with photographs, make a pre-selection of the clips that you really need and get rid of the rest. I do the first pre-selection straight on the camera.
After reading this post I'm going to start experimenting with other formats than ProRes for the internet projects.
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Old June 20th, 2010, 10:13 PM   #10
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Working with LT now...

I just shot a bunch of interviews today with my 7D and am in the process of transcoding the H.264 clips to ProRes LT for use in my fcp timeline. I am using mpeg streamclip to transcode rather than compressor as I have read in some of the other forums. This will do the exact same job, right?

The video was shot in 720 60fps, so there are certain clips that I am going to do some time remapping with in after effects.... I'm hoping just to export the files in LT and keep the workflow even with all the codecs.

I've got my fcp previewing on a 42" HD TV, and the footage looks stunning in the timeline, even when comparing the same clip to ProRes regular, so I'm hoping going with the LT and saving the space on the hard drive was a good move.....
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