What Codec Should You Use When Rendering 4K Stock Footage Clips? January 6, 2015
If you’re a seasoned stock footage producer who has recently upgraded to 4K, you probably already know that your file sizes are suddenly exploding. This leads to the $64,000 question: What codec should I use to export my final videos?
I understand where you’re at: you don’t want to compromise your quality, but at the same time, you don’t want to spend hours uploading gigabytes and gigabytes of new footage to multiple agencies. There has to be a happy medium.
Lucky for you, there are several codec options that may fit the bill. In my humble opinion, your codec choice probably should be determined by the content you’re compressing and the camera you used to shoot with.
For example, if you shoot with a Sony PMW-F55 CineAlta 4K Digital Cinema Camera at 600 Mbps using the XAVC codec with 4:2:2 colorspace, you probably would want your final codec choice to take advantage of all your camera’s inherent abilities and features. After all, you wouldn’t want to throw a big chunk of your cinematography work out the window by rendering in a substandard delivery codec.
The opposite is true, too.
If you just don’t have the budget to shoot with a high-end professional camera like the F55, or you don’t use an external recorder like the Atmos Shogun, you probably don’t need to “upscale” your raw footage into a codec that is too big for your needs. That would be like delivering one gallon of water in a 50 gallon drum. Sure, you’d get the water to its destination, but it would be overkill.
There are many codec choices for you to use, but here are a few that will get you started. Keep in mind, there really is no one solution to fit everyone’s needs. I, myself use all the following codecs depending on the material I’m rendering.
Most of the options discussed below are accepted at popular stock footage agencies. They are also widely compatible with most modern editors without the need for sketchy third-party software installations. There are new codecs on the horizon that look promising, like H.265, but you’d be wise to stick with the standards for the time being. You don’t want an angry email from a customer who downloaded your MXF file and can’t figure out how to play it.
This codec choice (sometimes labeled as AVC1) might be a bit controversial, and it’s commercial usability might still be in question, but in my opinion, it’s the best for those shooters (like myself) who use prosumer gear.
I primarily shoot 4K with my Panasonic GH4, using the internal SD card. When recording internally, this camera shoots 4K at 100Mbps in H.264. The H.264 codec sacrifices some quality aspects for more reasonable file sizes. One compromise is that it shoots in 4:2:0 colorspace. So, my codec-of-choice for material shot with this camera is H.264. I render MP4 files at 100Mbps, equal to that which my camera shoots.
Until H.265 becomes the norm for 4K, I think this codec is a solid choice.
- manageable file sizes and quicker uploads
- compatible as-is with most editing systems
- since many prosumer cameras shoot this codec to begin with, you’re not losing much (if any) quality by offering H.264 as your final renders
- average colorspace, not a good option for heavy grading or chroma key shots (but you can “convert” the GH4’s 4K 4:2:0 shots to HD 4:4:4)
- since it’s heavily compressed, it may take more horsepower to edit and play on non-linear timelines
- not an intra-frame codec (frames are “grouped” together and share compression, so high motion shots might not look good)
- no embedded alpha channel options
- if using Adobe Premiere Pro or After Effects, some H.264 frame size and frame rate exporting options are only available when using the stand-alone Media Encoder.
This legacy codec is a good selection if you want a bit more “umph” out of your footage. It’s not nearly as compressed as H.264, so the file sizes are larger (but not as large as the next codec option).
You may want to use this codec if you shoot with prosumer gear, but just can’t see yourself rendering final movies in H.264. You may also want to choose QuickTime PhotoJPEG if the agency you submit to doesn’t accept H.264.
- most stock agencies accept PhotoJPEG-compressed 4K clips, so it’s a good choice if you submit the same clip(s) to multiple agencies (iStock is the lone hold-out on P-JPEG 4K files)
- 100% compatible with all QuickTime-enabled systems, and easily played on most timelines
- great colorspace (up to 4:4:4, but if you shoot less than 4:2:2, you’d only gain filesize with zero benefit)
- export virtually any resolution and frame rate
- good choice for non-camera generated video (animations, graphics, or time lapses)
- intra-frame codec (each frame is individually compressed)
- filesizes are larger than H.264, sometimes unnecessarily so
- while it can be 4:4:4, PhotoJPEG is still an 8-bit codec, so you may see “banding” in subtle color gradients
- no embedded alpha channel options
- use a quality compression between 75%-95%, depending on your shot
- for high motion or shots with high detail, use a higher quality percentage
- avoid 100%, as this makes your file 4:4:4, which is undoubtedly overkill for stock footage
This is an excellent choice if you shoot using high-end professional equipment. It has all the quality options you’d need if you wanted to give your customers the very best. But this does come at a price: file sizes are very large, especially for 4K.
If you shoot with high-end professional gear, or use an external recorder that records your raw footage at a quality level that would justify the use of this codec, then this is the perfect choice. It supports up to 12-bit color depth, and up to 4:2:2 colorspace. So this would be a fine choice for chroma key shots if your camera shoots 4:2:2 or 4:4:4 in the first place.
ProRes comes in various “flavors,” and you should choose the one that best suits your needs. Basically, the only difference among all variants of ProRes is the bitrate. ProRes Proxy has the lowest bitrate and probably not accepted at most agencies, and ProRes HQ and 4444 has the highest.
Actual bitrates depend on the resolution you’re exporting. For HD, ProRes HQ delivers about 220 Mbps. At 4K, Prores HQ offers about 730 Mbps. On the lighter side, an HD ProRes LT file is roughly 104 Mbps, and a 4K Prores LT file is about 340 Mbps.
- great quality
- compatible with any QuickTime-equipped editing workstation
- up to 4:4:4 colorspace, great for chroma key shots and heavy grading
- good option for rendering animations or graphics (non-camera footage)
- intra-frame codec (each frame is individually compressed)
- up to 12-bit color depth (with ProRes 4444)
- embedded alpha channel (with ProRes 4444)
- ALL agencies accept ProRes 4K clips, so it’s a good choice if you submit the same clip(s) to multiple agencies (iStock, however requires the much larger ProRes HQ format)
- very big file sizes
- while you can play ProRes on a QuickTime-equipped Windows machine, you really can only create “true” ProRes files on a Macintosh with this $50 software package installed (but there are options for PC users if you want to risk using a non-Apple branded product)
- very big file sizes (did I already say that?)
Now, all that gobbledygook talk is great, but what about some examples?
Here’s a shot I grabbed while in Barcelona, Spain in 2014 (available here in full 4K glory on Pond5, BTW). I shot this with my Panasonic GH4. I did very little color grading on this clip, and rendered it out in the three codecs I talked about above. Feel free to download these (watermarked) examples and examine them for yourself. Hopefully they will help you with your codec decisions.
ZIP H.264 at 100Mbps, 74 MB, Length = 5 seconds
ZIP PhotoJPEG at 440Mbps, 274 MB, Length = 5 seconds
ZIP ProRes LT at 390Mbps, 243 MB, Length = 5 seconds
ZIP ProRes HQ at 880Mbps, 548 MB, Length = 5 seconds
Personally, I see no difference in any of those versions. The 74 MB H.264 clip looks just as good to me as the 548 MB ProRes HQ file. While they may be technically different, aesthetically, these examples all look virtually identical. And in the stock footage business, aesthetic characteristics trumps technical features. I strongly believe most customers make their buying decisions solely on what they see in the preview, not from what cryptic details may or may not be hidden under the “technical information” button.
So, to lessen my upload burden, I choose to upload the smaller H.264 file when I submit 4K video clips shot with my GH4. If the buyer prefers one codec to another, they can transcode it themselves after purchasing. The buyer converting H.264 files to ProRes (or a codec of their choice) after downloading would be no different than me doing it before uploading. (Interesting side note: do you know what codec ShutterStock customers get if they opt for the HD version of your beautifully-rendered ProRes 4K file? You guessed it: H.264.)
Of course, your situation will be different than mine. If you shoot with a Atmos Shogun attached to a Sony a7s, or you like to do heavy color correcting in post, then by all means, go with a codec that you think takes the best advantage of your workflow. If your shooting and editing environment is more like mine, then you may benefit from choosing a more bandwidth-friendly codec. And since many stock agencies offer on-demand transcoding for the customer after the purchase, this just all might be a mute point anyhow.
But the choice is ultimately yours. Just don’t lose any sleep over it.