David Newman, Senior Director of Software Engineering for GoPro answered some questions that I had after writing my story on transcoding GoPro files to ProRes 422. I kept wondering if the intermediate step of transcoding — as I have been doing over the years — is the best approach for handling and processing GoPro Cineform files. From his answers that I received by email I learned it isn’t necessary.
Q: The “old” GoPro Studio Pro application was capable of exporting to ProRes but lacked the template features and the features that turn it into a lightweight NLE. The new version misses ProRes export. I can see why you added the templates capabilities etc., but why did you decide against including ProRes support?
A: Exporting from the Edit Room of GoPro Studio doesn’t make sense for intermediates, it is for final/locked colour edits. The Import Room is where you make intermediates for use in any NLE. Studio is designed primarily for GoPro users, but the MP4 files are compatible with most other workflows. For those feeling ProRES or DNxHD is a must, they can use MPEGStreamClip or Red Giant’s Bullet Proof, etc.
Q: How does the Cineform codec that Final Cut Pro X and other NLEs can work with comparse to ProRes and DNxHD to name two that are optimised for “their” respective NLEs?
A: The CineForm codec has everything ProRes/DNxHD have and more. CineForm is a 10/12-bit and fast I-frame Wavelet. ProRes/DNxHD are 10/12-bit fast I-frame DCT (Discrete Cosine Transform) – all can be MOV wrapped.
How to create intermediates with GoPro Studio Pro
To create intermediate Cineform files with GoPro Studio Pro, you’ll need to stay in the Import room, says mr. Newman. Here is how you go about. Import your GoPro MP4 clip as usual.
Set your advanced features, such as 422 quality and whether you want to get rid of the fisheye effect. Set your output folder. Hit the Convert button and let GoPro Studio convert the file. That’s it. You now have a Cineform clip to ingest in your NLE, Da Vinci Resolve or whatever else you want to use.
CineForm adds Active Metadata, resolutions up to 8K+, native RAW and 3D support. DNxHD, ProRes and CineForm can all be used in all major NLEs natively. GoPro users clearly benefit from CineForm if they use Active Metadata development for the Protune camera modes, resolutions over HD and/or 3D.
For other HD modes ProRes/DNxHD work fine, but they offer no true advantage and would be a disadvantage within the GoPro Studio Pro editor as ProRes/DNxHD do not have the required features to natively edit here (all the colour and image framing is CineForm Active Metadata.)
Q: If I want to use GoPros, let’s say a whole bunch of them integrated with a broadcast system and transcoded afterwards to different formats, would you advise to use Episode, Squeeze, another transcoding engine or GoPro Studio Pro, and what would the workflow be?
A: The workflow is identical to any other digital intermediate workflow. H.264 .MP4 long-GOP files are transcoded into a preferably deep pixel (10-bit or better), 4:2:2 (or better), I-frame intermediate. GoPro needed to offer a cross-platform solution (that rules out ProRes) and resolution independent solution for all the camera modes (that rules out DNxHD which doesn’t support 960p, 1440p, 2.7k and 4k.)
Q: I know you can roundtrip between GPS and an NLE by way of the XML generated by GoPro Studio (like for colour grading in the app, etc) but are there pros who use this feature or do most pro users prefer to use SpeedGrade or Da Vinci?
You would not roundtrip, although the idea of using Studio for dailies and exporting an XML is being investigated. We have some great information about Active Metadata, no round tripping required for communicating colour correction between Studio and other NLEs. (Ed.: the files he mentions have been published by the Cineform team in 2010, but it seems like they are still relevant today). Geeky info on Active Metadata: http://cineform.com/pdfs/ActiveMetadata_Architecture.pdf and a fun application of its use http://cineform.blogspot.com/2010/03/automatic-remote-color-corrections-with.html.
Q: How do GoPro files behave in these colour grading apps, BTW? Which would be the best export format and would I be able to roundtrip with these as well?
A: Da Vinci Resolve is a native CineForm colour correction tool. It even supports the Active Metadata engine. SpeedGrade was native CineForm under Iridas, but I haven’t tried it since the Adobe acquisition as I found it difficult to use.