Cineform Express To SD

[Edgar Pitts]

Are there any aliasing issues with the Cineform Express files? Can you use these as a master if you only plan on outputting to SD? Are there any issues with Express files as it relates to downsampling from 4K?

Thanks.

Edgar Pitts
Producer
Jetrefilm Entertainment
http://www.jetrefilm.com

 

[David Newman]

The current CineForm Express file preset script generates 1024x512 (for 2:1 source of 2K/3K or 4K -- 1024x576 for 16x9 sources) which should be enough oversampling for many SD and web projects. Yet as this was decoded using one of the sub-resolution output from the R3D wavelet, it was not undergone an ideal downsampling, so for high-end work you will want at least an HD/2K decode and sample that to SD. Also the express file default to 4:2:2 yuv coding at medium quality, if you intend to master with them I would bump the quality to High or Filmscan1 (-q3 or -q4) and maybe set the coding to 4:4:4 (remove the -y switch.) None of these change the fast conversion speed, but it will incease the Express file bit-rate form 1.5-3MB/s up to 6-7MB/s (still tiny.)

 

[Christopher Grant Harvey]

David what is the best way to deliver SD and avoid aliasing issues using a CF workflow? Would the SetActiveMetadata debayer settings affect this at all?

I have *seen* better results going from R3D > HD 444 > then exporting to a SD CineForm AVI out of Premiere, with a little bit of sharpening and an unsharp mask.

Thanks.

 

[David Newman]

Christopher, this is exactly what I was decribing, using HD 444/422 first, will not use a wavelet sub-level which eliminates aliasing in the R3D source decoder. The disadvantage is only speed, the express resolution decodes from R3Ds are faster.

The SetActiveMetadata debayer setting only controls the CineForm RAW decoders, not R3D RAW decoder. If you convert R3D to CineForm RAW, using BatchRAW or the -r switch on R2CF, then yes the demosaic filter will impact (very subtly an SD export, has more impact at 4K and 2K/HD.) For BatchHD444 or any other non-raw setting the R3D demosaic is used.

 

[Christopher Grant Harvey]

Christopher, this is exactly what I was decribing, using HD 444/422 first, will not use a wavelet sub-level which eliminates aliasing in the R3D source decoder. The disadvantage is only speed, the express resolution decodes from R3Ds are faster.

So my current workflow seems fine > batch R3D to Express Files @ 1K > Edit > Relink to HD 444 > Export to whatever with some moderate post sharpening.

Cool.