Michael Phillips
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COW Coin
Forum Replies Created
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I think there is a misconception around “acceleration” with the DNxIO box. The hardware assist is for capture only from a signal based input up to 4K, not for playback .
Michael
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Looking forward to hearing your thoughts. I suspect your experience will be closer to the Ultrastudio 4K than Nitris.
Michael
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Did you try the uncompressed test just to see?
Michael
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Thanks for the follow up. Always appreciated.
I think you might be overly critical, but without seeing the actual files, it is difficult to tell. Are these 4K files you are linking to? If so, there can be differences in how the resize is affecting the overall quality as a link versus an actual transcode and you may be seeing some difference there. While Media Composer’s resize algorithms are good, they are great and do not optimize based on scaling up or scaling down.
A test I usually do is create DNxHD out of Resolve using it’s resizers and compare it to Media Composer for critical material. I tend to find Resolve consistently does a better job, even if fractionally better in some cases. As an example for another project I was doing, I referred to this difference in a blog I was writing on “portrait” editing where it did involve both a rotate and a resize and compared the output frames of Resolve and Media Composer.
https://24p.com/wordpress/?p=233
If 4K sources and finishing at 1080, there will be a downrez scaling operation somewhere in your pipeline. If those shots are critical, then you need to decide where that is being done in your workflow pipeline. DNxHD 175x has been used to finish many a broadcast show, so it may be something that is unique to your footage, lighting, angle, etc. A quick test would be to transcode those clips to uncompressed and see if you see the same thing. If it’s still there, then it is not the compression, but either your source material or the downrez (if greater than HD sources).
Michael
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John and Shane have pretty much covered all the different considerations. The issue with AMA linked to longGop and similar codecs is that it can work well for a while, then as you get more footage, timeline get longer or more complex, you want to do multicam, etc, the performance is just not there to what you expect it to be. Most production will take the transcode hit up front to eliminate that right off the bat.
The Avid storage calculator hasn’t been updated in years, but still works for DNxHD workflows. This will give you an idea of how much storage to plan for given your total acquiaition.
https://www.avid.com/US/resources/avid-storage-calculator
Michael
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Were the original files batch imported or AMA linked/transcoded, or a combination of both? You can batch import to a sequence, for those clips, you need to batch import back to the original master clip. For linking, then you are on the right track.
Michael
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Yeah… I guess there is that too… 😉
I guess I’m still searching or the word that defines progressive or interlace… raster was a good one. dammit.
Michael
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Whether it is progressive or interlace.
Michael
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For a 1080 delivery coming from RED 4K, you will be fine with a “1/2 debayer good” quality setting. You may want to create DNxHD is Redcine X directly as it is a faster decode of R3D as it uses GPU whereas MC does not.
You may decide to work with a proxy DNxHD to start. then relink and transcode the seqeunce only, or transcode directly to a finishing quality data rate like 175x (or 180x in your case at 25fps). All that depends on amount of footage, turnaround time, etc.
Here is a LUT I made in Resolve as .cube that you can import into MC and use via Source Settings. All it does is changes Saturation to 0.
Here is a download link to the LUT:
Michael
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R3D is a tough codec to play within Avid and AMA is only used to access and then let you choose selected and transcode to a DNx codec for ease in editorial. Make sure you select debayer settings for transcode/render in Media Creation settings.
You can do the ASC CDL trick I describe which is easily reversible and behave like a LUT. Let me see what I got for LUTs to use in MC – it may have one for B&W, but you can make a .cube in Resolve that has saturation set to 0 or create a top video track in MC where you have it set to 0. They all behave the same way and depends on where you want to insert it in the pipeline.
Michael