Apple’s Pro Res – Which One?

There are 5 members of the Apple Pro Res family and they are all based on the same basic properties. Pro Res is an “I frame” codec, meaning that each frame is a self contained picture, needing no help from adjacent pictures to determine its content. This is different from other video compression schemes such as MPEG2 Long GOP (group of pictures). This format has only one (1) complete picture for every 15 frames of video, the other 14 using the information from adjacent partial frames to complete each frame. There are pros and cons to each format.

1. “I frame” video is less processor intensive during the editing process but since the data rates are higher you need a bigger pipe between hard drive and computer to get all that information in and out. I frame codecs can also take more editing cycles before they start to lose quality.

2. Long GOP takes up less space on your hard drive and therefore a smaller in and out pipe, but is much more processor intensive because each time you make an edit cut the computer has to “conform” or rebuild each 15 frame segment of video.

Apple invented the Pro Res family to strike a balance between processor intensive codecs and the heavy I frame codecs that took up enormous space on hard drives and huge data transfer rates (in and out pipes).

So which flavour of Pro Res is right for you? Well since you asked let’s get to it.

1. Pro Res 422 Proxy is the lowest data rate member of the family and as the name implies it’s primarily used as an “offline” codec. Think of its use as a ‘placeholder’ for editing. When the edit is complete it can easily be replaced by the higher resolution codec that was shot at the same time. All the flavours of Pro Res have the same frame size so you can easily swap out one for the other without having to change the original sizes of your graphics, pictures etc.

2 Pro Res 422 LT is perfect for ENG style shooting where you know there will be minimal colour correction or anything else that will modify the video no more than a few times during the edit process. Shooting ‘talking heads’ for example, would be a perfect use for Pro Res 422 LT.

3. Pro Res 422 is the highest most of us will need to get great quality that can stand up to many editing cycles without falling apart. Under normal circumstances here is virtually no perceivable difference between this and Pro Res 422 HQ.

4. Where you would use Pro Res 422 HQ is when you plan to do green screen shooting, as this codec will have a better chance of pulling high quality keys. If I was shooting a full length feature film I would also use this codec.

5. Pro Res 4×4. This is the ultimate Pro Res family member that was only recently added. It is of course, full raster with high data rates and works in the 4:4:4 colour space with an alpha channel. If you’re going to use tons of special effects, compositing, rotoscoping etc. then this one’s for you.

Most of us will use Pro Res 422 and Pro Res 422 LT and will rarely have a need for anything else. For a more complete story you can find Apple’s white paper on the Pro Res family here.

– Don


Written by:

Don Greening is the owner and both senior editor and videographer for Reeltime Videoworks. His arts background as a classical musician and composer gives him an uncompromising eye and ear for detail that is very important in video production. Don also hones his technical skills by updating them through courses at Emily Carr Institute of Art + Design.

  • Chris Grindley-Ferris

    Great piece! Thanks for the info. Deciding which codecs to use is not my strongest suite,

  • We’ve used ProRes 4×4 as the editing codec for our upcoming short film. Our reasoning is to keep as much fidelity to our film negative as possible … editing for projection on a large screen makes codec artifacts oh-so-much-more noticeable.