Issues with dpx files in AE

[Walter Soyka]

[Mike Stadnyckyj] “I tried importing a dpx sequence into AE CS4 and got an error stating “the chosen file cannot be read as Cineon FIDO or SMPTE DPX”. I thought this was odd so I tried it in AE CS5.5 and had no issues at all. The only problem is all my favoured plugins are installed in CS4 so I prefer using that over CS5.5. Does anybody know why CS4 is giving me this message?”

Bizarre. I don’t know why you’re getting that message, but if you can’t solve it, I’d suggest you could work around the issue by using CS5.5 to import the DPX sequence and render it out untouched to another format.

[Mike Stadnyckyj] “My second question is in regard to the bits per channel. What is the proper course of action when dealing with the 10 bpc dpx files in After Effects, which only allows me to work in 8,16 or 32 bits?”

Don’t work in 8 bpc to avoid truncation. AE will dither down higher bit depths as necessary.

There’s a big difference between 16 bpc and 32 bpc (floating point) calculations. Floating point calculations will not clip, so you can have lighter-than-white or darker-than-black results. This particularly affects blurs, glows, and blend modes, but it also more subtly affects the interaction among stacked effects, because you can push and pull the image practically indefinitely.

See Color depth and high dynamic range color [link] for more.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events

[Mike Stadnyckyj]

Thank you for the help, that’s great. As far as the CS4 issue it is indeed puzzling.

[Mike Stadnyckyj]

I came across another question when exporting my dpx sequence. In the settings box for the output module I have the bpc set to my projects settings but if it’s 16 or 32 will it be saving as 10 bit none the less as it’s dpx?

Also the output profile takes it’s info from my working space, what happens if I have that set to none instead of sRGB or something like HDTV Rec.709. However i’m pretty sure the client is using sRGB, what effect does that have on their end?

Thanks

[Walter Soyka]

[Mike Stadnyckyj] “In the settings box for the output module I have the bpc set to my projects settings but if it’s 16 or 32 will it be saving as 10 bit none the less as it’s dpx?”

Yes, AE will save out 10-bit DPX files.

[Mike Stadnyckyj] “Also the output profile takes it’s info from my working space, what happens if I have that set to none instead of sRGB or something like HDTV Rec.709. However i’m pretty sure the client is using sRGB, what effect does that have on their end?”

You can set a separate output color profile in the Color Management tab of the output module.

DPX is a pretty broad and flexible format. If you have questions on your specific deliverables, you should talk to your client about what they require.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events