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AMA vs Transcoding Reasons/Performance when using RAW video or AVI

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Jared Jones
AMA vs Transcoding Reasons/Performance when using RAW video or AVI
on Dec 30, 2014 at 9:01:46 am

So I'm basically brand new to Avid Media Composer 8.3 and so far I love everything about the workflow. However one new thing that comes up that has me a *little* bit confused is AMA linking and Avid transcoding. So first off I'd like to say that I've researched it and have read other threads on this forum regarding the differences. Instead my question relates to transcoded material and how it'll link against the original source material.

So let's say that my source material is RED Raw Footage, or perhaps something already compressed like an MP4. Now I know from experimentation that if I edit with my source material in Avid that the program will run very slow. So basically what you're supposed to do is transcode your source material into Avid's format so that you can edit more efficiently. Now for my question...

If I transcode aren't I losing the RAW video quality? What I'd really prefer is if I could transcode the video, edit with the transcoded material, and then export the project using ALL the effects I applied but instead of using the transcoded video it would instead use my source material. (a.k.a RED Raw). This would be great because all the edits would continue to be in Red Raw and there wouldn't be any compression. So how does this work? Before Media Composer 8.3 there was no support for 4K or UHD video. So how did Hollywood editors edit in Avid and then export in 4K? I'm assuming they transcoded into 1080p Avid and then exported against their source material.

How do I go about doing this? Thanks! :)


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Richard Sanchez
Re: AMA vs Transcoding Reasons/Performance when using RAW video or AVI
on Dec 30, 2014 at 6:11:35 pm

Before Avid supported 4k, you'd export your project with a cut list that would go to your finishing house. In the film days, your cut list would refer to the negative so that it could be cut and a film print made. Nowadays, you're exporting an EDL that refers to the source video files. You can conform to 4k in DaVinci Resolve, Baselight, Quantel Pablo, whatever your finishing system was. That will be made to create your DCP. The Avid was meant to cut with offline media and then conform later. Even with 4k editing, it will be most practical in most cases to continue cutting at 1080p using DNxHD36 media and then conforming to 4k at the end.

Regarding transcoding versus working RAW, yes you're losing a generation and therefore you're losing some quality by transcoding. Since you mentioned MP4, that's a format that is already so compressed that you're probably not losing much more that wasn't already lost in the camera's compression itself. In the case of Alexa, now you can consolidate the ProRes444 directly into Avid so the footage is rewrapped but not transcoded. Again, if you need to finish in 1080p, even though DNxHD175x is a lossy codec, it's a very high quality codec and projects finish on it all the time. If you need to deliver 2k and above, you'll most likely be conforming in a system that can handle it. When you asked how do Hollywood editors edit at 4k, they don't (mostly). They'll cut at 1080, and then conform to 4K.

Also, just to nitpick, you mentioned RAW wasn't compressed, but it's very compressed. I believe most RED cams default to 8:1 compression and even at it's least compressed variant, is still 3:1.

Richard Sanchez
Los Angeles, CA

"We are the facilitators of our own creative evolution." - Bill Hicks


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Michael Phillips
Re: AMA vs Transcoding Reasons/Performance when using RAW video or AVI
on Dec 30, 2014 at 9:09:11 pm

Some RAW formats are compressed such as R3D (RED) as you mention, and others are not, such as ARRIRAW and DNG. It always pays to get all the details of the format being used to plan accordingly.

Michael


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Robert Ober
Re: AMA vs Transcoding Reasons/Performance when using RAW video or AVI
on Dec 30, 2014 at 8:09:30 pm

RAO's stock answer number one:

Start in Resolve


As mentioned above you can start in another package, transcode and include an AAF or EDL or XML, and send that to Avid. Once the edit is done you export an AAF, EDL, or similar and send that to the package you started in. You can then reconnect to the camera originals.

Many folks, including notalentwannabes like myself use this workflow. I start in Resolve and finish usually in Resolve. If you want to output 4K you will need the licensed version. The Lite version I believe works now up to and including UHD. By the way, when folks say Conform, think reconnect to camera originals.

Resolve and packages designed for Dailes can make multiple copies of your camera originals and you can do a quick color correction pass referred to as a one-light.

Hope that helps,
Robert

Robert A. Ober
IT Consultant, Vidcaster, & Freelancer
http://www.infohou.com
Houston, TX


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Pat Horridge
Re: AMA vs Transcoding Reasons/Performance when using RAW video or AVI
on Dec 31, 2014 at 9:59:23 am

Many RAW formats are compressed some aren't. But you can't export out the RAW media as a cut sequence.
You would either transcode to a finishing resolution making what adjustments you want to the RAW. Or transcode to a lower res for fast editing and relink later in the grade to the RAW.
but which ever route you won't output RAW.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
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