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Transcode or not? (hassle notwithstanding)
I’m imminent to make the switch from FCP7
I tested PProCC with a 4K edit of DSLR-native mp4 clips (GH4), editing on a 720 sequence. This 4K-onto-720 paradigm is best for our fast-turnaround documentary projects, for highly efficient scaling and cropping within the original material.
After I color corrected the final edit and rendered all the clips on the sequence, I exported that sequence as a ProRes 422 “master” (the client deliverable preference).
Now so I may learn and understand in the language of professional everyday users:
– If I’m not experiencing too much sluggishness as I cut, do I ever need to transcode DSLR-native clips before editing if ProRes is my final step?
(or put another way–)
– When I “export” a rendered edit sequence out to a ProRes file, is that file any worse quality than if I had been editing ProRes transcodes in the first place?Please forget for a moment the time and drive space required to pre-transcode camera clips for a project— will the final master be actually, mathematically, theoretically different in image quality one way or the other?
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6 Replies
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Maximum quality is achieved when you edit the source files. However,
1) The difference in quality should be visually undetectable.
2) If the source files are H.264 or other highly compressed codec, it might take longer to render the edited sequence from H.264 compared to rendering from ProRes files.
3) If color correction is performed with a different application you should export using a low compression intermediate codec (like ProRes) for grading, or use a Dynamic Link between Premiere Pro and another Adobe app. -
Thank you Ivan, that’s very clear! It made me realize I have one more question if I may–
After I render a sequence of color-corrected, scaled camera-native H.264 clips, it plays smoothly and looks sharp. But what am I watching exactly, a proxy of some kind? Because if I then export the rendered sequence that can take a while too.
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Assuming you aren’t creating preview files, what you see on the monitor within Premiere Pro is an uncompressed, fully subsampled (4:4:4), RGB representation of the clips with effects applied. A ProRes master file would have 4:2:2 or 4:4:4 sub-sampling with low compression. When exporting to H.264 the video gets reconfigured to high compression 4:2:0 Y’CbCr.
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That’s excellent info, thank you!
If I’m not creating preview files, then it seems like the version I’ve rendered in my sequence is already superior in spec to the ProRes 422 I usually export as a “master”.
How would I export that sequence “preview” with its awesome spec– what format is that?
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DPX, but file size will be very large. ProRes 4:4:4 generates smaller files with very good quality. If you are ultimately exporting to H.264 ProRes 4:2:2 is fine.
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Thanks very much Ivan, this info is a great step for me to start using PPro as a key business tool!
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