I spent a lot of time this last week thinking about media. Partly, I was planning my webinar on media management. But, partly, too, because so many of the questions I get these days revolve around media.
I first wrote these “Media Planning Guidelines” as a series of bullet points for my weekly Tip Letter on Codecs & Media. I wanted to help us think about media and the storage necessary for video editing. I’m expanding these Guidelines in this article to help explain my thinking.
1. Deadlines. If deadlines are tight AND you are not adding a lot of effects, you can edit H.264 or HEVC directly in your NLE. Otherwise, transcode all highly-compressed media into an easier-to-edit intermediate format, such as ProRes, DNx or GoPro Cineform.
NOTE: Here’s a short video that explains why H.264 and HEVC are hard to edit.
Too often, we make decisions about media based on the amount of available storage. While storage is not free, neither is our time, the effort we make to create high quality images, or the impact lower bit-depth has on color grading and effects.
2. Image quality. Image quality is not lost in transcoding (converting) a highly-compressed video format into ProRes. Transcoding is like pouring a 5-gallon bucket filled with water into a bathtub. The space you are pouring the media into is so vast, nothing gets lost. Plus, the bathtub is so big, that you can add and mix whatever other elements you want without losing water by having it slop over the sides.
NOTE: Transcoding does not improve image quality compared to when it was shot. But it does mean less will be lost during editing, effects and export.
3. Colors. Transcoding media also converts a highly-compressed 8-bit format into a 10-bit far-less-compressed format.
NOTE: There are almost no truly uncompressed media formats. Even raw formats need to have color lost during capture reconstructed during the de-Bayering process.
Converting media to a 10-bit depth also expands grayscale values from 256 values to 1,024. Maximum black or white don’t change, but the subtlety between them expands. It also increases the range of colors that can be expressed from 16.7 million to 1.1 billion! This means that 10-bit depth media provides smoother gradients, better looking effects, and more accurate color grading.
4. Camera media. If the media was shot by a camera, transcode into ProRes 422. This version of ProRes matches how most cameras record color information.
5. Computer media. If the media was created on a computer, transcode into ProRes 4444. Computer-generated media has far more, and far more saturated, colors than images shot with a camera. ProRes 4444 preserves all that color information. However, in doing so, it generates much larger files.
6. Log or raw media. If the media was shot in log or raw formats, edit it natively and create the rough cut using proxies. The benefit to shooting log or raw files comes at the end of the editing process by providing much more flexibility in the color grade. Until then, editors are simply looking at ugly images.
Seeing as, in general, log or raw files are both very big and very ugly in their native format, it makes sense to work with proxies during most of the edit. There’s no reason to stress your system processing large files when you aren’t using them for the quality they provide.
NOTE: There are two ways to apply LUTs to proxy files: When you first create the proxy file you can “burn” the LUT into the proxy. Or, you can apply LUTs to the proxy file after it is created, using either Premiere or Final Cut. The benefit to burning LUTs into proxies is that the proxies can be created long before the edit process begins, meaning everyone who sees the proxies has a sense of what the final images might look like. The benefit to adding LUTs during editing is that you can change them at any time, to keep tweaking the look. Both Adobe Media Encoder and Apple Compressor can add LUTs when creating proxy files.
7. Frame rate. Always shoot the frame rate you need to deliver. Changing frame rates after production is complete almost always looks “jittery.”
Any video format is composed of a series of still images displayed sequentially at a fixed rate. The only way to change the frame rate is to change the speed of a clip, remove frames or extend the duration of a frame.
The easiest frame rate conversion is either doubling the frame rate (i.e. from 30 to 60) or cutting the frame rate in half (i.e. from 48 to 24). These conversions are the least likely to cause jitter. Anything else will probably cause stuttering during movement.
NOTE: While it is possible to create new video by morphing one frame into the next, the results vary widely in quality. As well, technique works best when used for short periods of time, for example, transitions or special effects.
8. Proxies. Proxies are your friend. Use proxies to create a rough cut when using HDR or raw media; or frame sizes larger than 4K.
For some reason, many editors feel that editing with proxies shows “weakness.” To me, it shows intelligence. The only time we need the full-quality image is for color grading and final output. The rest of the time, as long as we can clearly see the image – which all proxy formats support – we don’t need to process those massive files simply to do a rough cut. Converting to and accessing proxies in Final Cut or Premiere have never been easier. Use them.
9. File size. Media files are getting bigger. Frame sizes are at 4K and heading ot 8K, which increases file sizes 4X. HDR requires a minimum of 10-bit and some cameras are shooting 12-bit. Every 2-bit increase in bit-depth increases file size 4X.
NOTE: As an example, if a 1080p file has a size of 100 MB, the same file at 4K is about 400 MB (4X) and the same file at 8K is about 1.6 GB (16X). In addition, HDR multiplies file size for each frame size by 2-4X.
10. Storage bandwidth. Color grading high-quality 4K HDR media can easily require over 500 MB/second of data bandwidth! Make sure your storage is fast enough.
11. Storage capacity. Always have a reserve budget to buy more high-performance storage. You’ll need it. No production ever shot less media than they planned.
12. Test your workflow. Always allow time to test your entire workflow from capture to final output before starting production. It is much easier to find and fix problems when not facing a looming deadline. “I didn’t have time to test!” is never a good excuse.
SUMMARY
Yes, there are exceptions to these guidelines, but not in most cases. As I’ve written before, computers today are more than fast enough for most media. The real stress is not on our computers, but on our storage.
