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16bit file formats?
Hi everyone. In a pickle here!
I’ve got an edit which is comprised of 3-plate VFX composites, with keyed out footage over CGI backplates.
It now needs to be graded, so i’ve arranged the whole thing in Premiere.I have assumed that it’s best to give the colourist as much bit-depth as possible, so I’ve tried to keep the entire project 16bit, however I’m having some issues with this.
As far as i can see the only format that I can import into Premiere which is 16bit are PNG sequences (TIFs come out grey and glitchy). They import Ok, but Premiere gets sooooo slow and in some cases won’t even render segments of the sequence out.
I’m worried this is going to cause problems in the grade.
So my question is: Is this the best practice? Are PNG sequences a bad idea, what can speed it up? Are 16bit files even necessary for colour grading?
Thanks in advance!
Kim
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6 Replies
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Though I work for Adobe, I would say that I’m not the best guy when it comes to these kinds of discussions. However, I guess the most basic question is this: what is the final deliverable? If it is 8-bit or even 10-bit, then chances are you can carefully convert the footage to the appropriate format and hand that over. If it is some film output, then look at DPX file format which I believe (I don’t have Premiere in front of me) can export at a higher bit depth.
HTH,
Dennis -
Thanks for your reply Dennis. The very final deliverable would be at 8-bit as it would be for web and youtube. My reason for wanting to keep it 16 bit would be to allow the colourist maximum colour information to maintain resolution. Quite a lot of the footage is dark and so he may choose to stretch the tones out a bit, so I’d want to avoid banding. I also aim to keep as much resolution throughout the pipeline as a matter of best practice.
Thanks I will look into DPX to see if that helps!
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A tip is to check your workflow in that you actually get proper bit depth in and out. Premiere is quite an odd bird in this regard.
– DPX I think works in RGB 10- or 16-bit but I can’t say for sure.
– TIFF is limited to RGBA 8-bpp which is extremely sad.
– In general I’ve seen odd things exporting. Stills seem to fall back to 8-bpp which is frustrating as hell.Depending on your system / workflow you do have codecs like ProRes and Cineform that are 10-bit or greater. ProRes 4444 is RGB 12-bit with a 16-bit alpha. That said they are compressed.
To Adobe: PLEASE make Premiere, After Effects and Photoshop consistent in format support. It’s quite terribad now.
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Thanks for your reply. I discovered the Project Manager function in Premiere and managed to transcode everything to ProRes 4444, which has made the playback really smooth again and retained my alpha channels for the VFX plates.
I think the lesson here was not to try and edit using lossless PNG sequences and instead convert to a quicker mezzanine codec. 12-bits of depth is more than enough considering that the footage is only 10-bit, and my background plates don’t require any colour correction.
Thanks!
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having lot of confusions. which is good format for colour grading
TIFF OR DPX
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DPX is better than TIFF, especially if you are going between RGB and Y’CbCr (H.264, x.264, H.265, MPEG2, WMV, Flash). However, if your editing workflow is 8-bit RGB there is no harm in delivering TIFF files for grading (although JPEG2000 would produce smaller files). The more common choice would be 10-bit, all-intra, 422/444 codecs such as ProRes, DNxHD, AVC-I, or Cineform which provide a good tradeoff between image quality and file size.
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